Dry reforming of methane(DRM) is an attractive technology for utilizing the greenhouse gases(CO_(2) and CH_(4)) to produce syngas. However, the catalyst pellets for DRM are heavily plagued by deactivation by coking, w...Dry reforming of methane(DRM) is an attractive technology for utilizing the greenhouse gases(CO_(2) and CH_(4)) to produce syngas. However, the catalyst pellets for DRM are heavily plagued by deactivation by coking, which prevents this technology from commercialization. In this work, a pore network model is developed to probe the catalyst deactivation by coking in a Ni/Al_(2)O_(3) catalyst pellet for DRM. The reaction conditions can significantly change the coking rate and then affect the catalyst deactivation. The catalyst lifetime is higher under lower temperature, pressure, and CH_(4)/CO_(2) molar ratio, but the maximum coke content in a catalyst pellet is independent of these reaction conditions. The catalyst pellet with larger pore diameter, narrower pore size distribution and higher pore connectivity is more robust against catalyst deactivation by coking, as the pores in this pellet are more difficult to be plugged or inaccessible.The maximum coke content is also higher for narrower pore size distribution and higher pore connectivity, as the number of inaccessible pores is lower. Besides, the catalyst pellet radius only slightly affects the coke content, although the diffusion limitation increases with the pellet radius. These results should serve to guide the rational design of robust DRM catalyst pellets against deactivation by coking.展开更多
Nowadays,combined steam and dry reforming of methane(CSDRM)is viewed as a new alternative for the production of high-quality syngas(termed as"metgas",H2:CO of 2.0)suitable for subsequent synthesis of methano...Nowadays,combined steam and dry reforming of methane(CSDRM)is viewed as a new alternative for the production of high-quality syngas(termed as"metgas",H2:CO of 2.0)suitable for subsequent synthesis of methanol,considered as a promising renewable energy vector to substitute fossil fuel resources.Adequate operation conditions(molar feed composition,temperature and pressure)are required for the sole production of"metgas"while achieving high CH4,CO2 and H2O conversion levels.In this work,thermodynamic equilibrium analysis of CSDRM has been performed using Gibbs free energy minimization where;(i)the effect of temperature(range:200-1000℃),(ii)feed composition(stoichiometric ratio as compared to a feed under excess steam or excess carbon dioxide),(iii)pressure(range:1-20 bar)and,(iv)the presence of a gaseous diluent on coke yields,reactivity levels and selectivity towards"metgas"were investigated.Running CSDRM at a temperature of at least 800℃,a pressure of 1 bar and under a feed composition where CO2-H2O/CH4 is around 1.0,are optimum conditions for the theoretical production of"metgas"while minimizing C(S)formation for longer experimental catalytic runs.A second part of this work presents a review of the recent progresses in the design of(principally)Ni-based catalysts along with some mechanistic and kinetic modeling aspects for the targeted CSDRM reaction.As compared to noble metals,their high availability,low cost and good intrinsic activity levels are main reasons for increasing research dedications in understanding deactivation potentials and providing amelioration strategies for further development.Deactivation causes and main orientations towards designing deactivationresistant supported Ni nanoparticles are clearly addressed and analyzed.Reported procedures based on salient catalytic features(i.e.,acidity/basicity character,redox properties,oxygen mobility,metal-support interaction)and recently employed innovative tactics(such as confinement within mesoporous systems,stabilization through core shell structures or on carbide surfaces)are highlighted and their impact on Ni0reactivity and stability are discussed.The final aspect of this review encloses the major directions and trends for improving synthesis/preparation designs of Ni-based catalysts for the sake of upgrading their usage into industrially oriented combined reforming operations.展开更多
Several mesoporous silicas with different morphologies were controllably prepared by sol-gel method with adjustable ratio of dual template,and they were further impregnated with aqueous solution of nickel nitrate,foll...Several mesoporous silicas with different morphologies were controllably prepared by sol-gel method with adjustable ratio of dual template,and they were further impregnated with aqueous solution of nickel nitrate,followed by calcination in air.The synthesized silica supports and supported nickel samples were characterized using N_2-adsorption/desorption,X-ray diffraction(XRD),H_2 temperature-programmed reduction(H_2-TPR),Scanning electron microscope(SEM),Transmission electron microscope(TEM) and thermo-gravimetric analysis(TGA-DTG) techniques.The Ni nanoparticles supported on shell-like silica are highly dispersed and yielded much narrower nickel particle-size than those on other mesoporous silica.The methane reforming with dioxide carbon reaction results showed that Ni nanoparticles supported on shell-like silica carrier exhibited the better catalytic performance and catalytic stability than those of nickel catalyst supported on other silica carrier.The thermo-gravimetric analysis on used nickel catalysts uncovered that catalyst deactivation depends on the type and nature of the coke deposited.The heterogeneous nature of the deposited coke was observed on nickel nanoparticles supported on spherical and peanut-like silica.Much narrower and lower TGA derivative peak was founded on Ni catalyst supported on the shell-like silica.展开更多
Dry reforming of methane(DRM) involves the conversion of carbon dioxide(CO_(2)) and methane(CH_(4)) into syngas(a mixture of hydrogen, H_(2), and carbon monoxide, CO), which can then be used to produce a wide range of...Dry reforming of methane(DRM) involves the conversion of carbon dioxide(CO_(2)) and methane(CH_(4)) into syngas(a mixture of hydrogen, H_(2), and carbon monoxide, CO), which can then be used to produce a wide range of products by means of Fischer–Tropsch synthesis. DRM has gained much attention as a means of mitigating damage from anthropogenic greenhouse gas(GHGs) emissions to the environment and instead utilizing these gases as precursors for value-added chemicals or to synthesize sustainable fuels and chemicals. Carbon deposition or coke formation, a primary cause of catalyst deactivation, has proven to be a major challenge in the development of DRM catalysts. The use of nickel-and cobalt-based catalysts has been extensively explored for DRM for their high activity and low cost but suffer from poor stability due to coke formation that has hindered their commercialization. Numerous articles have reviewed the various aspects of catalyst deactivation and strategies for mitigation, but few has focused on the benefit of bimetallic catalysts for mitigating coke formation. Bimetallic catalysts, often improve the catalytic stability over their monometallic counterparts due to synergistic effects resulting from two metal-tometal interactions. This review will cover DRM literature for various bimetallic catalyst systems, including the effect of supports and promoters, on the mitigation of carbonaceous deactivation.展开更多
The conversion of methane and carbon dioxide into syngas(dry reforming of methane;DRM)has attracted attention owing to the potential to reuse greenhouse gases.Titanium dioxide(TiO_(2))-based photocatalysts,which have ...The conversion of methane and carbon dioxide into syngas(dry reforming of methane;DRM)has attracted attention owing to the potential to reuse greenhouse gases.Titanium dioxide(TiO_(2))-based photocatalysts,which have been widely commercialized owing to their high efficiency,non-toxicity,and low cost,are strongly desired in DRM.Here,we report a monoclinic-phase TiO_(2)-B nanobelts-supported rhodium(Rh/TiO_(2)-B nanobelts)catalyst that efficiently promotes DRM under ultraviolet light irradiation at low temperatures.Photogenerated holes in the TiO_(2)-B nanobelts were used to oxidize methane,while the electrons were trapped in rhodium to reduce carbon dioxide.Rh/TiO_(2)-B nanobelts exhibited considerably higher durability and activity than Rh-loaded conventional TiO_(2)(anatase and rutile),owing to the lattice and/or surface oxygen reactivity in TiO_(2)-B nanobelts,which was suggested by X-ray photoelectron spectroscopy measurements and photocatalytic performance tests under an atmosphere of methane alone.This study paves the path for the effective utilization of methane by constructing active TiO_(2)-based nanometal photocatalysts.展开更多
The cognition of active sites in the Ni-based catalysts plays a vital role and remains a huge challenge in improving catalytic performance of low temperature CO_(2) dry reforming of methane(LTDRM).In this work,typical...The cognition of active sites in the Ni-based catalysts plays a vital role and remains a huge challenge in improving catalytic performance of low temperature CO_(2) dry reforming of methane(LTDRM).In this work,typical catalysts of SiO_(2) and γ-Al_(2)O_(3) supported Ni and Ni-Ce were designed and prepared.Importantly,the difference in the chemical speciations of active sites on the Ni-based catalysts is revealed by advanced characterizations and further estimates respective catalytic performance for LTDRM.Results show that larger[Ni0-]particles mixed with[Ni-O-Sin])species on the Ni/SiO_(2)(R)make CH_(4) excessive decomposition,leading to poor activity and stability.Once the Ce species is doped,however,superior activity(59.0%CH_(4) and 59.8%CO_(2) conversions),stability and high H_(2)/CO ratio(0.96)at 600℃ can be achieved on the Ni-Ce/SiO_(2)(R),in comparison with other catalysts and even reported studies.The improved performance can be ascribed to the formation of integral([Ni0_(n))]-[CeⅢ-□-CeⅢ])species on the Ni-Ce/SiO_(2)(R)catalyst,containing highly dispersed[Ni]particles and rich oxygen vacancies,which can synergistically establish a new stable balance between gasification of carbon species and CO_(2) dissocia-tion.With respect to Ni-Ce/γ-Al_(2)O_(3)(R),the Ni and Ce precursors are easily captured by extra-framework Al_(n)-OH groups and further form stable isolated([Ni0_(n))]-[Ni-O-Al_(n)])and[CeⅢ-O-Al_(n)]species.In such a case,both of them preferentially accelerate CO_(2) adsorption and dissociation,causing more car-bon deposition due to the disproportionation of superfuous CO product.This deep distinguishment of chemical speciations of active sites can guide us to further develop new efficient Ni-based catalysts for LTDRM in the future.展开更多
Metal oxides have been used as the supports for heterogeneous catalysis formany years,but they still suffer from coking in some high-temperature applications.The main reasons for coking are the uncontrollable dissocia...Metal oxides have been used as the supports for heterogeneous catalysis formany years,but they still suffer from coking in some high-temperature applications.The main reasons for coking are the uncontrollable dissociation of C-H and the overbalance between carbon deposition and removal.Herein,we find a boron nitride(BN)-immobilized Ni catalyst shows unprecedented coking resistance in dry reforming of methane via the incomplete decomposition of methane.Unlike the Ni-based catalysts supported by traditional metal oxides,BN-supported Ni accelerates the first C-H dissociation while inhibiting the breaking of the final C-H bond;hence,the suppression of the complete decomposition of methane thoroughly addresses the coking issue.This work reveals the fundamental reason for the coking resistance over BN-supported Ni catalysts is selective activation of the C-H bond,which can provide an inspiring idea for other applications.展开更多
Dry reforming of methane(DRM)process has attracted much attention in recent years for the direct conversion of CH_4 and CO_(2)into high-value-added syngas.The key for DRM was to develop catalysts with high activity an...Dry reforming of methane(DRM)process has attracted much attention in recent years for the direct conversion of CH_4 and CO_(2)into high-value-added syngas.The key for DRM was to develop catalysts with high activity and stability.In this study,LaNiO_(3)was prepared by the sol-gel,co-precipitation,and hydro-thermal methods to explore the influence of preparation methods on the catalyst structure and DRM reaction performance.The regeneration properties of the used LaNiO_(3)catalysts were also investigated under steam,CO_(2),and air atmospheres,respectively.The results showed that LaNiO_(3)prepared by sol-gel method showed the best DRM performance at 750℃.The DRM performance of the samples prepared by hydro-thermal method was inhibited at 750℃due to the residual of Na^(+)ions during the preparation process.The regeneration tests showed that none of the three atmospheres could restore LaNiO_(3)perovskite phase in the samples,but they could eliminate the carbon deposits in the samples during the DRM reaction,so the samples could maintain stable DRM performance at different cycling stages.展开更多
A series of ternary perovskite type oxides LaNi1-xCuxO3(x = 0.2,0.4,0.6,0.8,and 1.0) were synthesized via the sol-gel method in propionic acid.Partial substitution of Ni by Cu showed higher activities and selectivitie...A series of ternary perovskite type oxides LaNi1-xCuxO3(x = 0.2,0.4,0.6,0.8,and 1.0) were synthesized via the sol-gel method in propionic acid.Partial substitution of Ni by Cu showed higher activities and selectivities towards syngas products.LaNi0.8Cu0.2O3 was the most active toward the CH4 and CO2 conversions,and was selective for syngas products.Temperature-programmed reduction results showed that the addition of Cu facilitates the reduction of Ni3+ to Ni0,which is the main reason for the higher performance of this catalyst.展开更多
As a vital energy resource and raw material for many industrial products,syngas(CO and H_(2))is of great significance.Dry reforming of methane(DRM)is an important approach to producing syngas(with a hydrogen-to-carbon...As a vital energy resource and raw material for many industrial products,syngas(CO and H_(2))is of great significance.Dry reforming of methane(DRM)is an important approach to producing syngas(with a hydrogen-to-carbon-monoxide ratio of 1:1 in principle)from methane and carbon dioxide,with a lower operational cost as compared to other reforming techniques.However,many pure metallic catalysts used in DRM face deactivation issues due to coke formation or sintering of the metal particles.A systematic search for highly efficient metallic catalysts,which reduce the reaction barriers for the rate-determining steps and resist carbon deposition,is urgently needed.Nickel is a typical low-cost transition metal for activating the C–H bond in methane.In this work,we applied a two-step workflow to search for nickel-based bimetallic catalysts with doping metals M(M-Ni)by combining density functional theory(DFT)calculations and machine learning(ML).We focus on the two critical steps in DRM—CH_(4) and CO_(2) direct activations.We used DFT and slab models for the Ni(111)facet to explore the relevant reaction pathways and constructed a data set containing structural and energetic information for representative M-Ni systems.We used this dataset to train ML models with chemical-knowledge-based features and predicted CH_(4) and CO_(2) dissociation energies and barriers,which revealed the composition–activity relationships of the bimetallic catalysts.We also used these models to rank the predicted catalytic performance of candidate systems to demonstrate the applicability of ML for catalyst screening.We emphasized that ML ranking models would be more valuable than regression models in high-throughput screenings.Finally,we used our trained model to screen 12 unexplored M-Ni systems and showed that the DFT-computed energies and barriers are very close to the ML-predicted values for top candidates,validating the robustness of the trained model.展开更多
Highly dispersed Ni catalyst and alkaline promoters supported by mesoporous SiO_(2)nanospheres were synthesized and applied as an active and stable catalyst for dry reforming of methane(DRM).The as-prepared Ni/MgO-mSi...Highly dispersed Ni catalyst and alkaline promoters supported by mesoporous SiO_(2)nanospheres were synthesized and applied as an active and stable catalyst for dry reforming of methane(DRM).The as-prepared Ni/MgO-mSiO_(2)catalyst showed stable conversions of CH4 and CO_(2)around 82%and 85%in 120 h of DRM reaction,which was superior in performance compared to similar catalysts in literatures.Based on the transmission electron microscope(TEM)images,energy-dispersive spectroscopy(EDS),CO-pulse adsorption,temperature programmed reduction of the oxidized catalysts by hydrogen(H_(2)-TPR),X-ray photoelectron spectroscopy(XPS),temperature-programmed desorption of CO_(2)(CO_(2)-TPD),and thermal gravitational analysis(TGA),the promotion effect of MgO on the Ni catalyst was systematically studied.The introduction of Mg^(2+)in synthesis enhanced the interaction between Ni^(2+)and mSiO_(2),which led to a high dispersion of active centers and a strong“metal–support”interactions to inhibit the sintering and deactivation of Ni at reaction temperatures.On the other hand,Ni and MgO nanoparticles formed adjacently on mSiO_(2),where the“Ni-MgO”interface not only improved the Ni0 distribution and promoted the cracking of CH_(4)but also promoted the activation of CO_(2)and the elimination of carbon deposits.A high and stable conversion of CH4 and CO_(2)were then achieved through the synergistic effect of Ni catalyst,MgO promoter,and mSiO_(2)support.展开更多
A series of Ni catalysts supported on alumina with different Ce contents(1.0%–6.0%,mass fraction)was prepared by the impregnation method and used for dry reforming of methane(DRM)at a relatively low temperature of 65...A series of Ni catalysts supported on alumina with different Ce contents(1.0%–6.0%,mass fraction)was prepared by the impregnation method and used for dry reforming of methane(DRM)at a relatively low temperature of 650°C.The promotion effect of Ce with different loading amounts on the physicochemical properties of the catalysts was systematically characterized by transmission electron microscopy(TEM),X-ray diffraction(XRD),N_(2) adsorption-desorption,thermo elemental IRIS Intrepid inductively coupled plasma atomic emission spectrometer(ICP-AES),UV-visible diffuse reflectance spectroscopy(UV-Vis DRS),Fourier transformation infrared(FTIR)spectra,H_(2)-temperature programmed reduction(H_(2)-TPR)analysis,H_(2)-temperature programmed desorption(H_(2)-TPD),and The X-ray photoelectron spectroscopy(XPS)techniques.The results indicate that all the catalysts mainly exist in the NiAl_(2)O_(4) phase after being calcined at 750°C with small Ni particle sizes due to the strong metal-support interaction derived from the reduction of the NiAl_(2)O_(4) phase.The Ce-promoted catalysts show better catalytic performance as well as the resistance against sintering of Ni particles and deposition of carbon compared to the Ni/Al_(2)O_(3) catalyst.The Ni-6Ce/Al_(2)O_(3) exhibits the best catalytic stability and coke resistance among the four catalysts studied,which is due to its small Ni nanoparticles sizes,excellent reducibility as well as high amount of active oxygen species.In a 400 h stability test for DRM reaction at 650°C,Ni-6Ce/Al_(2)O_(3) exhibits less coke deposition and small growth of Ni nanoparticles.This work provides a simple way to preparing the Ni-Ce/Al_(2)O_(3) catalyst with enhanced catalytic performance in DRM.The Ni-6Ce/Al_(2)O_(3) catalyst has great potential for industrial application due to its anti-sintering ability and resistance to carbon deposition.展开更多
Designing and tailoring metal-support interaction in Ni-based catalysts with plentiful interfacial sites is of significant interest for achieving a targeted catalytic performance in dry reforming of methane (DRM),but ...Designing and tailoring metal-support interaction in Ni-based catalysts with plentiful interfacial sites is of significant interest for achieving a targeted catalytic performance in dry reforming of methane (DRM),but remains as a challenging task.In this work,Ni/Al_(2)O_(3)and Ni/CeO_(2)-Al_(2)O_(3)catalysts with the same strong metal-support interaction(SMSI) but distinct interface structure are developed by an improved evaporation-induced self-assembly method using pseudobohemite gel as aluminum source.Ni/CeO_(2)-Al_(2)O_(3)exhibits superior catalytic activity and stability in DRM in comparison with Ni/Al_(2)O_(3).The highest CH4and CO_(2)conversion reaches at 71.4%and 82.1%for Ni/CeO_(2)-Al_(2)O_(3),which are higher than that of 64.3% and 75.6% for Ni/Al_(2)O_(3)at 700℃.The SMSI effect in Ni/CeO_(2)-Al_(2)O_(3)provides more active interfacial sites with less coke deposition,and promotes the generation of active formate species which are the key intermediates for DRM.The findings of the present work could possibly pave the way for fabricating catalysts with SMSI strategy for efficient heterogeneous catalysis.展开更多
This paper brings the comparison of performances of CO_(2)conversion by plasma and plasma-assisted catalysis based on the data collected from literature in this field,organised in an open access online database.This t...This paper brings the comparison of performances of CO_(2)conversion by plasma and plasma-assisted catalysis based on the data collected from literature in this field,organised in an open access online database.This tool is open to all users to carry out their own analyses,but also to contributors who wish to add their data to the database in order to improve the relevance of the comparisons made,and ultimately to improve the efficiency of CO_(2)conversion by plasma-catalysis.The creation of this database and database user interface is motivated by the fact that plasma-catalysis is a fast-growing field for all CO_(2)conversion processes,be it methanation,dry reforming of methane,methanolisation,or others.As a result of this rapid increase,there is a need for a set of standard procedures to rigorously compare performances of different systems.However,this is currently not possible because the fundamental mechanisms of plasma-catalysis are still too poorly understood to define these standard procedures.Fortunately however,the accumulated data within the CO_(2)plasma-catalysis community has become large enough to warrant so-called“big data”studies more familiar in the fields of medicine and the social sciences.To enable comparisons between multiple data sets and make future research more effective,this work proposes the first database on CO_(2)conversion performances by plasma-catalysis open to the whole community.This database has been initiated in the framework of a H_(2)0_(2)0 European project and is called the“PIONEER Data Base”.The database gathers a large amount of CO_(2)conversion performance data such as conversion rate,energy efficiency,and selectivity for numerous plasma sources coupled with or without a catalyst.Each data set is associated with metadata describing the gas mixture,the plasma source,the nature of the catalyst,and the form of coupling with the plasma.Beyond the database itself,a data extraction tool with direct visualisation features or advanced filtering functionalities has been developed and is available online to the public.The simple and fast visualisation of the state of the art puts new results into context,identifies literal gaps in data,and consequently points towards promising research routes.More advanced data extraction illustrates the impact that the database can have in the understanding of plasma-catalyst coupling.Lessons learned from the review of a large amount of literature during the setup of the database lead to best practice advice to increase comparability between future CO_(2)plasma-catalytic studies.Finally,the community is strongly encouraged to contribute to the database not only to increase the visibility of their data but also the relevance of the comparisons allowed by this tool.展开更多
Synthesis gas, composed of H2 and CO, is an important fuel which serves as feedstock for industrially relevant processes, such as methanol or ammonia synthesis. The efficiency of these reactions depends on the H2: CO ...Synthesis gas, composed of H2 and CO, is an important fuel which serves as feedstock for industrially relevant processes, such as methanol or ammonia synthesis. The efficiency of these reactions depends on the H2: CO ratio, which can be controlled by a careful choice of reactants and catalyst surface chemistry.Here, using a combination of environmental scanning electron microscopy(ESEM) and online mass spectrometry, direct visualization of the surface chemistry of a Ni catalyst during the production of synthesis gas was achieved for the first time. The insertion of a homebuilt quartz tube reactor in the modified ESEM chamber was key to success of the setup. The nature of chemical dynamics was revealed in the form of reversible oxide-metal phase transitions and surface transformations which occurred on the performing catalyst. The oxide-metal phase transitions were found to control the production of synthesis gas in the temperature regime between 700 and 900 ℃ in an atmosphere relevant for dry reforming of methane(DRM, CO2: CH4=0.75). This was confirmed using high resolution transmission electron microscopy imaging, electron energy loss spectroscopy, thermal analysis, and C18O2 labelled experiments.Our dedicated operando approach of simultaneously studying the surface processes of a catalyst and its activity allowed to uncover how phase transitions can steer catalytic reactions.展开更多
Plasma-based CO_(2)conversion is promising for carbon capture and utilization.However,inconsistent reporting of the performance metrics makes it difficult to compare plasma processes systematically,complicates elucida...Plasma-based CO_(2)conversion is promising for carbon capture and utilization.However,inconsistent reporting of the performance metrics makes it difficult to compare plasma processes systematically,complicates elucidating the underlying mechanisms and compromises further development of this technology.Therefore,this critical review summarizes the correct definitions for gas conversion in plasma reactors and highlights common errors and inconsistencies observed throughout literature.This is done for pure CO_(2)splitting,dry reforming of methane and CO_(2)hydrogenation.We demonstrate that the change in volumetric flow rate is a critical aspect,inherent to these reactions,that is often not correctly taken into account.For dry reforming of methane and CO_(2)hydrogenation,we also demonstrate inconsistent reporting of energy efficiency,and through numerical examples,we show the significance of these deviations.Furthermore,we discuss how to measure changes in volumetric flow rate,supported by data from two experimental examples,showing that the sensitivity inherent to a standard component and a flow meter is essential to consider when deriving the performance metrics.Finally,some general recommendations and good practices are provided.This paper aims to be a comprehensive guideline for authors,to encourage more consistent calculations and stimulate the further development of this technology.展开更多
Plasma-catalytic dry reforming of CH_(4)(DRM) is promising to convert the greenhouse gasses CH_(4) and CO_(2) into value-added chemicals, thus simultaneously providing an alternative to fossil resources as feedstock f...Plasma-catalytic dry reforming of CH_(4)(DRM) is promising to convert the greenhouse gasses CH_(4) and CO_(2) into value-added chemicals, thus simultaneously providing an alternative to fossil resources as feedstock for the chemical industry. However, while many experiments have been dedicated to plasma-catalytic DRM, there is no consensus yet in literature on the optimal choice of catalyst for targeted products,because the underlying mechanisms are far from understood. Indeed, plasma catalysis is very complex,as it encompasses various chemical and physical interactions between plasma and catalyst, which depend on many parameters. This complexity hampers the comparison of experimental results from different studies, which, in our opinion, is an important bottleneck in the further development of this promising research field. Hence, in this perspective paper, we describe the important physical and chemical effects that should be accounted for when designing plasma-catalytic experiments in general, high-lighting the need for standardized experimental setups, as well as careful documentation of packing properties and reaction conditions, to further advance this research field. On the other hand, many parameters also create many windows of opportunity for further optimizing plasma-catalytic systems.Finally, various experiments also reveal the lack of improvement in plasma catalysis compared to plasma-only, specifically for DRM, but the underlying mechanisms are unclear. Therefore, we present our newly developed coupled plasma-surface kinetics model for DRM, to provide more insight in the underlying reasons. Our model illustrates that transition metal catalysts can adversely affect plasmacatalytic DRM, if radicals dominate the plasma-catalyst interactions. Thus, we demonstrate that a good understanding of the plasma-catalyst interactions is crucial to avoiding conditions at which these interactions negatively affect the results, and we provide some recommendations for improvement. For instance, we believe that plasma-catalytic DRM may benefit more from higher reaction temperatures,at which vibrational excitation can enhance the surface reactions.展开更多
The synthesis of mesoporous zeolite-anchored atomically dispersed metal catalysts(ADCs)is a considerable challenge in chemistry and materials science.Here we report the synthesis of atomically dispersed cationic nicke...The synthesis of mesoporous zeolite-anchored atomically dispersed metal catalysts(ADCs)is a considerable challenge in chemistry and materials science.Here we report the synthesis of atomically dispersed cationic nickel-confined mesoporous ZSM-48(ANMZ-48)by in situ hydrothermal reaction employing a designed tri-functional metal complex template,by which the triquaternary ammonium groups in the hydrophilic region direct the formation of ZSM-48 zeolite;the aromatic groups in the hydrophobic tail generate the mesopores through π-π stacking;and the complexes formed by nickel ions coordinated with terpyridyl groups generate atomically dispersed Ni2+confined in zeolite frameworks due to the strong sintering resistance generated by the strong coordination interaction.The ANMZ-48 is consisting of stacking of sheet-like ZSM-48 domains connected by multiply crystal twinning sharing the common(011)plane,generating abundant of imbedded mesopores with the uniform thickness of~2.4 nm and with the width of 10-50 nm.The excellent catalytic activity and stability of ANMZ-48 were also reflected in the dry reforming of methane(DRM)reaction.展开更多
Solar-driven CO_(2)-to-fuel conversion assisted by another major greenhouse gas CH_(4)is promising to concurrently tackle energy shortage and global warming problems.However,current techniques still suffer from drawba...Solar-driven CO_(2)-to-fuel conversion assisted by another major greenhouse gas CH_(4)is promising to concurrently tackle energy shortage and global warming problems.However,current techniques still suffer from drawbacks of low efficiency,poor stability,and low selectivity.Here,a novel nanocomposite composed of interconnected Ni/MgAlOx nanoflakes grown on SiO_(2)particles with excellent spatial confinement of active sites is proposed for direct solar-driven CO_(2)-to-fuel conversion.An ultrahigh light-to-fuel efficiency up to 35.7%,high production rates of H_(2)(136.6 mmol min^(-1)g^(-1))and CO(148.2 mmol min^(-1)g^(-1)),excellent selectivity(H_(2)/CO ratio of 0.92),and good stability are reported simultaneously.These outstanding performances are attributed to strong metal-support interactions,improved CO_(2)absorption and activation,and decreased apparent activation energy under direct light illumination.MgAlO_(x)@SiO_(2)support helps to lower the activation energy of CH^(*) oxidation to CHO^(*) and improve the dissociation of CH_(4)to CH_(3)^(*) as confirmed by DFT calculations.Moreover,the lattice oxygen of MgAlO_(x) participates in the reaction and contributes to the removal of carbon deposition.This work provides promising routes for the conversion of greenhouse gasses into industrially valuable syngas with high efficiency,high selectivity,and benign sustainability.展开更多
The adverse effects of global warming and climate change have driven the exploration of feasible routes for CO_(2) capture,storage,conversion and utilization.The processes related to CO_(2) conversion in high-temperat...The adverse effects of global warming and climate change have driven the exploration of feasible routes for CO_(2) capture,storage,conversion and utilization.The processes related to CO_(2) conversion in high-temperature electrochemical devices(HTEDs)using dense ceramic membranes are particularly appealing due to the simultaneous realization of highly efficient CO_(2) conversion and value-added chemical production as well as the generation of electricity and storage of renewable energy in some cases.Currently,most studies are focused on the two processes,CO_(2) electrolysis and H2O/CO_(2) co-electrolysis in oxygen-conducting solid oxide electrolysis cell(O-SOEC)reactors.Less attention has been paid to other meaningful CO_(2)-conversion-related processes in HTEDs and systematic summary and analysis are currently not available.This review will fill the gap and classify the CO_(2)-conversion-related processes in HTEDs reported in recent years into four types accord-ing to the related reactions,including assisted CO_(2) reduction to CO,H2O and CO_(2) co-conversion,dry reforming of methane and CO_(2) hydrogenation.Firstly,an overview of the fundamentals of HTED processes is presented,and then the related mechanism and research progress of each type of reactions in different HTEDs are elucidated and concluded accordingly.The remaining major technical issues are also briefly introduced.Lastly,the main challenges and feasible solutions as well as the future prospects of HTEDs for CO_(2)-conversion-related processes are also discussed in this review.展开更多
基金financially supported by the National Natural Science Foundation of China (22078090 and 92034301)the Shanghai Rising-Star Program (21QA1402000)+1 种基金the Natural Science Foundation of Shanghai (21ZR1418100)the Open Project of State Key Laboratory of Chemical Engineering (SKL-ChE-21C02)。
文摘Dry reforming of methane(DRM) is an attractive technology for utilizing the greenhouse gases(CO_(2) and CH_(4)) to produce syngas. However, the catalyst pellets for DRM are heavily plagued by deactivation by coking, which prevents this technology from commercialization. In this work, a pore network model is developed to probe the catalyst deactivation by coking in a Ni/Al_(2)O_(3) catalyst pellet for DRM. The reaction conditions can significantly change the coking rate and then affect the catalyst deactivation. The catalyst lifetime is higher under lower temperature, pressure, and CH_(4)/CO_(2) molar ratio, but the maximum coke content in a catalyst pellet is independent of these reaction conditions. The catalyst pellet with larger pore diameter, narrower pore size distribution and higher pore connectivity is more robust against catalyst deactivation by coking, as the pores in this pellet are more difficult to be plugged or inaccessible.The maximum coke content is also higher for narrower pore size distribution and higher pore connectivity, as the number of inaccessible pores is lower. Besides, the catalyst pellet radius only slightly affects the coke content, although the diffusion limitation increases with the pellet radius. These results should serve to guide the rational design of robust DRM catalyst pellets against deactivation by coking.
基金financial support through the SOL-CARE(Energy-065,2016–2019)project(JC-ENERGY-2014 first call)。
文摘Nowadays,combined steam and dry reforming of methane(CSDRM)is viewed as a new alternative for the production of high-quality syngas(termed as"metgas",H2:CO of 2.0)suitable for subsequent synthesis of methanol,considered as a promising renewable energy vector to substitute fossil fuel resources.Adequate operation conditions(molar feed composition,temperature and pressure)are required for the sole production of"metgas"while achieving high CH4,CO2 and H2O conversion levels.In this work,thermodynamic equilibrium analysis of CSDRM has been performed using Gibbs free energy minimization where;(i)the effect of temperature(range:200-1000℃),(ii)feed composition(stoichiometric ratio as compared to a feed under excess steam or excess carbon dioxide),(iii)pressure(range:1-20 bar)and,(iv)the presence of a gaseous diluent on coke yields,reactivity levels and selectivity towards"metgas"were investigated.Running CSDRM at a temperature of at least 800℃,a pressure of 1 bar and under a feed composition where CO2-H2O/CH4 is around 1.0,are optimum conditions for the theoretical production of"metgas"while minimizing C(S)formation for longer experimental catalytic runs.A second part of this work presents a review of the recent progresses in the design of(principally)Ni-based catalysts along with some mechanistic and kinetic modeling aspects for the targeted CSDRM reaction.As compared to noble metals,their high availability,low cost and good intrinsic activity levels are main reasons for increasing research dedications in understanding deactivation potentials and providing amelioration strategies for further development.Deactivation causes and main orientations towards designing deactivationresistant supported Ni nanoparticles are clearly addressed and analyzed.Reported procedures based on salient catalytic features(i.e.,acidity/basicity character,redox properties,oxygen mobility,metal-support interaction)and recently employed innovative tactics(such as confinement within mesoporous systems,stabilization through core shell structures or on carbide surfaces)are highlighted and their impact on Ni0reactivity and stability are discussed.The final aspect of this review encloses the major directions and trends for improving synthesis/preparation designs of Ni-based catalysts for the sake of upgrading their usage into industrially oriented combined reforming operations.
基金supported by the Cultivation Project of Major Achievements Transformation of Sichuan Provincial Education Department(#14CZ0005)supported by the Natural Science Foundation of China(#21406184)
文摘Several mesoporous silicas with different morphologies were controllably prepared by sol-gel method with adjustable ratio of dual template,and they were further impregnated with aqueous solution of nickel nitrate,followed by calcination in air.The synthesized silica supports and supported nickel samples were characterized using N_2-adsorption/desorption,X-ray diffraction(XRD),H_2 temperature-programmed reduction(H_2-TPR),Scanning electron microscope(SEM),Transmission electron microscope(TEM) and thermo-gravimetric analysis(TGA-DTG) techniques.The Ni nanoparticles supported on shell-like silica are highly dispersed and yielded much narrower nickel particle-size than those on other mesoporous silica.The methane reforming with dioxide carbon reaction results showed that Ni nanoparticles supported on shell-like silica carrier exhibited the better catalytic performance and catalytic stability than those of nickel catalyst supported on other silica carrier.The thermo-gravimetric analysis on used nickel catalysts uncovered that catalyst deactivation depends on the type and nature of the coke deposited.The heterogeneous nature of the deposited coke was observed on nickel nanoparticles supported on spherical and peanut-like silica.Much narrower and lower TGA derivative peak was founded on Ni catalyst supported on the shell-like silica.
基金supported in part by the National Science Foundation under Grant No. 1955521the Donors of the American Chemical Society Petroleum Research Fund,for partial support of this work+1 种基金supported in part by the U.S. Department of Energy,Office of Science,Office of Workforce Development for Teachers and Scientists (WDTS)under the Science Undergraduate Laboratory Internships Program(SULI) and Visiting Faculty Program (VFP)Brookhaven National Laboratory (BNL) was supported by the U.S. Department of Energy (DOE),grant DE-SC0012704。
文摘Dry reforming of methane(DRM) involves the conversion of carbon dioxide(CO_(2)) and methane(CH_(4)) into syngas(a mixture of hydrogen, H_(2), and carbon monoxide, CO), which can then be used to produce a wide range of products by means of Fischer–Tropsch synthesis. DRM has gained much attention as a means of mitigating damage from anthropogenic greenhouse gas(GHGs) emissions to the environment and instead utilizing these gases as precursors for value-added chemicals or to synthesize sustainable fuels and chemicals. Carbon deposition or coke formation, a primary cause of catalyst deactivation, has proven to be a major challenge in the development of DRM catalysts. The use of nickel-and cobalt-based catalysts has been extensively explored for DRM for their high activity and low cost but suffer from poor stability due to coke formation that has hindered their commercialization. Numerous articles have reviewed the various aspects of catalyst deactivation and strategies for mitigation, but few has focused on the benefit of bimetallic catalysts for mitigating coke formation. Bimetallic catalysts, often improve the catalytic stability over their monometallic counterparts due to synergistic effects resulting from two metal-tometal interactions. This review will cover DRM literature for various bimetallic catalyst systems, including the effect of supports and promoters, on the mitigation of carbonaceous deactivation.
基金supported by a grant from the Japan Science and Technology Agency(JST)CREST(JPMJCR15P1)。
文摘The conversion of methane and carbon dioxide into syngas(dry reforming of methane;DRM)has attracted attention owing to the potential to reuse greenhouse gases.Titanium dioxide(TiO_(2))-based photocatalysts,which have been widely commercialized owing to their high efficiency,non-toxicity,and low cost,are strongly desired in DRM.Here,we report a monoclinic-phase TiO_(2)-B nanobelts-supported rhodium(Rh/TiO_(2)-B nanobelts)catalyst that efficiently promotes DRM under ultraviolet light irradiation at low temperatures.Photogenerated holes in the TiO_(2)-B nanobelts were used to oxidize methane,while the electrons were trapped in rhodium to reduce carbon dioxide.Rh/TiO_(2)-B nanobelts exhibited considerably higher durability and activity than Rh-loaded conventional TiO_(2)(anatase and rutile),owing to the lattice and/or surface oxygen reactivity in TiO_(2)-B nanobelts,which was suggested by X-ray photoelectron spectroscopy measurements and photocatalytic performance tests under an atmosphere of methane alone.This study paves the path for the effective utilization of methane by constructing active TiO_(2)-based nanometal photocatalysts.
基金financially supported by the National Natural Science Foundation of China (22006059, 21968015)National Engineering Laboratory for Flue Gas Pollutants Control Technology and Equipment (NEL-KF-201905)+1 种基金Applied Basic Research Program of Yunnan Province, China (202101AU070154, 2019FD034)Analysis and Testing Fund of Kunming University of Science and Technology (2020 T20200006)
文摘The cognition of active sites in the Ni-based catalysts plays a vital role and remains a huge challenge in improving catalytic performance of low temperature CO_(2) dry reforming of methane(LTDRM).In this work,typical catalysts of SiO_(2) and γ-Al_(2)O_(3) supported Ni and Ni-Ce were designed and prepared.Importantly,the difference in the chemical speciations of active sites on the Ni-based catalysts is revealed by advanced characterizations and further estimates respective catalytic performance for LTDRM.Results show that larger[Ni0-]particles mixed with[Ni-O-Sin])species on the Ni/SiO_(2)(R)make CH_(4) excessive decomposition,leading to poor activity and stability.Once the Ce species is doped,however,superior activity(59.0%CH_(4) and 59.8%CO_(2) conversions),stability and high H_(2)/CO ratio(0.96)at 600℃ can be achieved on the Ni-Ce/SiO_(2)(R),in comparison with other catalysts and even reported studies.The improved performance can be ascribed to the formation of integral([Ni0_(n))]-[CeⅢ-□-CeⅢ])species on the Ni-Ce/SiO_(2)(R)catalyst,containing highly dispersed[Ni]particles and rich oxygen vacancies,which can synergistically establish a new stable balance between gasification of carbon species and CO_(2) dissocia-tion.With respect to Ni-Ce/γ-Al_(2)O_(3)(R),the Ni and Ce precursors are easily captured by extra-framework Al_(n)-OH groups and further form stable isolated([Ni0_(n))]-[Ni-O-Al_(n)])and[CeⅢ-O-Al_(n)]species.In such a case,both of them preferentially accelerate CO_(2) adsorption and dissociation,causing more car-bon deposition due to the disproportionation of superfuous CO product.This deep distinguishment of chemical speciations of active sites can guide us to further develop new efficient Ni-based catalysts for LTDRM in the future.
基金financial support from the National Natural Science Foundation of China(grant nos.22006098 and 22125604)Shanghai Sailing Program(grant no.20YF1413300)+1 种基金J.D.thanks Dr.Lei Xie at Fudan University for fruitful discussions.The computational part is also supported by the JSPS KAKENHI(grant no.JP20K05217)the supercomputer at RCCS(grant no.22-IMS-C002),Okazaki,Japan.
文摘Metal oxides have been used as the supports for heterogeneous catalysis formany years,but they still suffer from coking in some high-temperature applications.The main reasons for coking are the uncontrollable dissociation of C-H and the overbalance between carbon deposition and removal.Herein,we find a boron nitride(BN)-immobilized Ni catalyst shows unprecedented coking resistance in dry reforming of methane via the incomplete decomposition of methane.Unlike the Ni-based catalysts supported by traditional metal oxides,BN-supported Ni accelerates the first C-H dissociation while inhibiting the breaking of the final C-H bond;hence,the suppression of the complete decomposition of methane thoroughly addresses the coking issue.This work reveals the fundamental reason for the coking resistance over BN-supported Ni catalysts is selective activation of the C-H bond,which can provide an inspiring idea for other applications.
基金financially supported by the funding from the National Natural Science Foundation of China(52176109)。
文摘Dry reforming of methane(DRM)process has attracted much attention in recent years for the direct conversion of CH_4 and CO_(2)into high-value-added syngas.The key for DRM was to develop catalysts with high activity and stability.In this study,LaNiO_(3)was prepared by the sol-gel,co-precipitation,and hydro-thermal methods to explore the influence of preparation methods on the catalyst structure and DRM reaction performance.The regeneration properties of the used LaNiO_(3)catalysts were also investigated under steam,CO_(2),and air atmospheres,respectively.The results showed that LaNiO_(3)prepared by sol-gel method showed the best DRM performance at 750℃.The DRM performance of the samples prepared by hydro-thermal method was inhibited at 750℃due to the residual of Na^(+)ions during the preparation process.The regeneration tests showed that none of the three atmospheres could restore LaNiO_(3)perovskite phase in the samples,but they could eliminate the carbon deposits in the samples during the DRM reaction,so the samples could maintain stable DRM performance at different cycling stages.
文摘A series of ternary perovskite type oxides LaNi1-xCuxO3(x = 0.2,0.4,0.6,0.8,and 1.0) were synthesized via the sol-gel method in propionic acid.Partial substitution of Ni by Cu showed higher activities and selectivities towards syngas products.LaNi0.8Cu0.2O3 was the most active toward the CH4 and CO2 conversions,and was selective for syngas products.Temperature-programmed reduction results showed that the addition of Cu facilitates the reduction of Ni3+ to Ni0,which is the main reason for the higher performance of this catalyst.
基金support provided by the American Chemical Society Petroleum Research Fund(PRF No.65744-DNI6).
文摘As a vital energy resource and raw material for many industrial products,syngas(CO and H_(2))is of great significance.Dry reforming of methane(DRM)is an important approach to producing syngas(with a hydrogen-to-carbon-monoxide ratio of 1:1 in principle)from methane and carbon dioxide,with a lower operational cost as compared to other reforming techniques.However,many pure metallic catalysts used in DRM face deactivation issues due to coke formation or sintering of the metal particles.A systematic search for highly efficient metallic catalysts,which reduce the reaction barriers for the rate-determining steps and resist carbon deposition,is urgently needed.Nickel is a typical low-cost transition metal for activating the C–H bond in methane.In this work,we applied a two-step workflow to search for nickel-based bimetallic catalysts with doping metals M(M-Ni)by combining density functional theory(DFT)calculations and machine learning(ML).We focus on the two critical steps in DRM—CH_(4) and CO_(2) direct activations.We used DFT and slab models for the Ni(111)facet to explore the relevant reaction pathways and constructed a data set containing structural and energetic information for representative M-Ni systems.We used this dataset to train ML models with chemical-knowledge-based features and predicted CH_(4) and CO_(2) dissociation energies and barriers,which revealed the composition–activity relationships of the bimetallic catalysts.We also used these models to rank the predicted catalytic performance of candidate systems to demonstrate the applicability of ML for catalyst screening.We emphasized that ML ranking models would be more valuable than regression models in high-throughput screenings.Finally,we used our trained model to screen 12 unexplored M-Ni systems and showed that the DFT-computed energies and barriers are very close to the ML-predicted values for top candidates,validating the robustness of the trained model.
基金supported by SINOPEC Research Institute of Petroleum Processing,the National Key Research and Development Program of China(No.2016YFB0701103)the National Natural Science Foundation of China(Nos.21972046 and 22172054).
文摘Highly dispersed Ni catalyst and alkaline promoters supported by mesoporous SiO_(2)nanospheres were synthesized and applied as an active and stable catalyst for dry reforming of methane(DRM).The as-prepared Ni/MgO-mSiO_(2)catalyst showed stable conversions of CH4 and CO_(2)around 82%and 85%in 120 h of DRM reaction,which was superior in performance compared to similar catalysts in literatures.Based on the transmission electron microscope(TEM)images,energy-dispersive spectroscopy(EDS),CO-pulse adsorption,temperature programmed reduction of the oxidized catalysts by hydrogen(H_(2)-TPR),X-ray photoelectron spectroscopy(XPS),temperature-programmed desorption of CO_(2)(CO_(2)-TPD),and thermal gravitational analysis(TGA),the promotion effect of MgO on the Ni catalyst was systematically studied.The introduction of Mg^(2+)in synthesis enhanced the interaction between Ni^(2+)and mSiO_(2),which led to a high dispersion of active centers and a strong“metal–support”interactions to inhibit the sintering and deactivation of Ni at reaction temperatures.On the other hand,Ni and MgO nanoparticles formed adjacently on mSiO_(2),where the“Ni-MgO”interface not only improved the Ni0 distribution and promoted the cracking of CH_(4)but also promoted the activation of CO_(2)and the elimination of carbon deposits.A high and stable conversion of CH4 and CO_(2)were then achieved through the synergistic effect of Ni catalyst,MgO promoter,and mSiO_(2)support.
基金supported by the National Natural Science Foundation of China(No.22088101)the fund of China Petroleum&Chemical Corporation(No.420068-2).
文摘A series of Ni catalysts supported on alumina with different Ce contents(1.0%–6.0%,mass fraction)was prepared by the impregnation method and used for dry reforming of methane(DRM)at a relatively low temperature of 650°C.The promotion effect of Ce with different loading amounts on the physicochemical properties of the catalysts was systematically characterized by transmission electron microscopy(TEM),X-ray diffraction(XRD),N_(2) adsorption-desorption,thermo elemental IRIS Intrepid inductively coupled plasma atomic emission spectrometer(ICP-AES),UV-visible diffuse reflectance spectroscopy(UV-Vis DRS),Fourier transformation infrared(FTIR)spectra,H_(2)-temperature programmed reduction(H_(2)-TPR)analysis,H_(2)-temperature programmed desorption(H_(2)-TPD),and The X-ray photoelectron spectroscopy(XPS)techniques.The results indicate that all the catalysts mainly exist in the NiAl_(2)O_(4) phase after being calcined at 750°C with small Ni particle sizes due to the strong metal-support interaction derived from the reduction of the NiAl_(2)O_(4) phase.The Ce-promoted catalysts show better catalytic performance as well as the resistance against sintering of Ni particles and deposition of carbon compared to the Ni/Al_(2)O_(3) catalyst.The Ni-6Ce/Al_(2)O_(3) exhibits the best catalytic stability and coke resistance among the four catalysts studied,which is due to its small Ni nanoparticles sizes,excellent reducibility as well as high amount of active oxygen species.In a 400 h stability test for DRM reaction at 650°C,Ni-6Ce/Al_(2)O_(3) exhibits less coke deposition and small growth of Ni nanoparticles.This work provides a simple way to preparing the Ni-Ce/Al_(2)O_(3) catalyst with enhanced catalytic performance in DRM.The Ni-6Ce/Al_(2)O_(3) catalyst has great potential for industrial application due to its anti-sintering ability and resistance to carbon deposition.
基金National Natural Science Foundation of China(Nos.22108189,21878203)Program for the Top Young and Middle-Aged Innovative Talents of Higher Learning Institutions of Shanxifinancial support by Shanxi-Zheda Institute of Ad-vanced Materials and Chemical Engineering(2021SX-TD005).
文摘Designing and tailoring metal-support interaction in Ni-based catalysts with plentiful interfacial sites is of significant interest for achieving a targeted catalytic performance in dry reforming of methane (DRM),but remains as a challenging task.In this work,Ni/Al_(2)O_(3)and Ni/CeO_(2)-Al_(2)O_(3)catalysts with the same strong metal-support interaction(SMSI) but distinct interface structure are developed by an improved evaporation-induced self-assembly method using pseudobohemite gel as aluminum source.Ni/CeO_(2)-Al_(2)O_(3)exhibits superior catalytic activity and stability in DRM in comparison with Ni/Al_(2)O_(3).The highest CH4and CO_(2)conversion reaches at 71.4%and 82.1%for Ni/CeO_(2)-Al_(2)O_(3),which are higher than that of 64.3% and 75.6% for Ni/Al_(2)O_(3)at 700℃.The SMSI effect in Ni/CeO_(2)-Al_(2)O_(3)provides more active interfacial sites with less coke deposition,and promotes the generation of active formate species which are the key intermediates for DRM.The findings of the present work could possibly pave the way for fabricating catalysts with SMSI strategy for efficient heterogeneous catalysis.
基金funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No.813393partially funded by the Portuguese FCT-Funda??o para a Ciência e a Tecnologia,under projects UIDB/50010/2020,UIDP/50010/2020 and PTDC/FIS-PLA/1616/2021。
文摘This paper brings the comparison of performances of CO_(2)conversion by plasma and plasma-assisted catalysis based on the data collected from literature in this field,organised in an open access online database.This tool is open to all users to carry out their own analyses,but also to contributors who wish to add their data to the database in order to improve the relevance of the comparisons made,and ultimately to improve the efficiency of CO_(2)conversion by plasma-catalysis.The creation of this database and database user interface is motivated by the fact that plasma-catalysis is a fast-growing field for all CO_(2)conversion processes,be it methanation,dry reforming of methane,methanolisation,or others.As a result of this rapid increase,there is a need for a set of standard procedures to rigorously compare performances of different systems.However,this is currently not possible because the fundamental mechanisms of plasma-catalysis are still too poorly understood to define these standard procedures.Fortunately however,the accumulated data within the CO_(2)plasma-catalysis community has become large enough to warrant so-called“big data”studies more familiar in the fields of medicine and the social sciences.To enable comparisons between multiple data sets and make future research more effective,this work proposes the first database on CO_(2)conversion performances by plasma-catalysis open to the whole community.This database has been initiated in the framework of a H_(2)0_(2)0 European project and is called the“PIONEER Data Base”.The database gathers a large amount of CO_(2)conversion performance data such as conversion rate,energy efficiency,and selectivity for numerous plasma sources coupled with or without a catalyst.Each data set is associated with metadata describing the gas mixture,the plasma source,the nature of the catalyst,and the form of coupling with the plasma.Beyond the database itself,a data extraction tool with direct visualisation features or advanced filtering functionalities has been developed and is available online to the public.The simple and fast visualisation of the state of the art puts new results into context,identifies literal gaps in data,and consequently points towards promising research routes.More advanced data extraction illustrates the impact that the database can have in the understanding of plasma-catalyst coupling.Lessons learned from the review of a large amount of literature during the setup of the database lead to best practice advice to increase comparability between future CO_(2)plasma-catalytic studies.Finally,the community is strongly encouraged to contribute to the database not only to increase the visibility of their data but also the relevance of the comparisons allowed by this tool.
文摘Synthesis gas, composed of H2 and CO, is an important fuel which serves as feedstock for industrially relevant processes, such as methanol or ammonia synthesis. The efficiency of these reactions depends on the H2: CO ratio, which can be controlled by a careful choice of reactants and catalyst surface chemistry.Here, using a combination of environmental scanning electron microscopy(ESEM) and online mass spectrometry, direct visualization of the surface chemistry of a Ni catalyst during the production of synthesis gas was achieved for the first time. The insertion of a homebuilt quartz tube reactor in the modified ESEM chamber was key to success of the setup. The nature of chemical dynamics was revealed in the form of reversible oxide-metal phase transitions and surface transformations which occurred on the performing catalyst. The oxide-metal phase transitions were found to control the production of synthesis gas in the temperature regime between 700 and 900 ℃ in an atmosphere relevant for dry reforming of methane(DRM, CO2: CH4=0.75). This was confirmed using high resolution transmission electron microscopy imaging, electron energy loss spectroscopy, thermal analysis, and C18O2 labelled experiments.Our dedicated operando approach of simultaneously studying the surface processes of a catalyst and its activity allowed to uncover how phase transitions can steer catalytic reactions.
基金financial support from the Fund for Scientific Research(FWO)Flanders(Grant ID 110221N)the European Research Council(ERC)under the European Union’s Horizon 2020 Research and Innovation Program(grant agreement No 810182-SCOPE ERC Synergy project)the Methusalem funding of the University of Antwerp。
文摘Plasma-based CO_(2)conversion is promising for carbon capture and utilization.However,inconsistent reporting of the performance metrics makes it difficult to compare plasma processes systematically,complicates elucidating the underlying mechanisms and compromises further development of this technology.Therefore,this critical review summarizes the correct definitions for gas conversion in plasma reactors and highlights common errors and inconsistencies observed throughout literature.This is done for pure CO_(2)splitting,dry reforming of methane and CO_(2)hydrogenation.We demonstrate that the change in volumetric flow rate is a critical aspect,inherent to these reactions,that is often not correctly taken into account.For dry reforming of methane and CO_(2)hydrogenation,we also demonstrate inconsistent reporting of energy efficiency,and through numerical examples,we show the significance of these deviations.Furthermore,we discuss how to measure changes in volumetric flow rate,supported by data from two experimental examples,showing that the sensitivity inherent to a standard component and a flow meter is essential to consider when deriving the performance metrics.Finally,some general recommendations and good practices are provided.This paper aims to be a comprehensive guideline for authors,to encourage more consistent calculations and stimulate the further development of this technology.
基金supported by the FWO-SBO project PlasMaCatDESIGN (FWO grant ID S001619N)the FWO fellowship of R. Michiels (FWO grant ID 1114921N)+2 种基金the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 810182 – SCOPE ERC Synergy project)funded by the Research Foundation - Flanders (FWO)the Flemish Government。
文摘Plasma-catalytic dry reforming of CH_(4)(DRM) is promising to convert the greenhouse gasses CH_(4) and CO_(2) into value-added chemicals, thus simultaneously providing an alternative to fossil resources as feedstock for the chemical industry. However, while many experiments have been dedicated to plasma-catalytic DRM, there is no consensus yet in literature on the optimal choice of catalyst for targeted products,because the underlying mechanisms are far from understood. Indeed, plasma catalysis is very complex,as it encompasses various chemical and physical interactions between plasma and catalyst, which depend on many parameters. This complexity hampers the comparison of experimental results from different studies, which, in our opinion, is an important bottleneck in the further development of this promising research field. Hence, in this perspective paper, we describe the important physical and chemical effects that should be accounted for when designing plasma-catalytic experiments in general, high-lighting the need for standardized experimental setups, as well as careful documentation of packing properties and reaction conditions, to further advance this research field. On the other hand, many parameters also create many windows of opportunity for further optimizing plasma-catalytic systems.Finally, various experiments also reveal the lack of improvement in plasma catalysis compared to plasma-only, specifically for DRM, but the underlying mechanisms are unclear. Therefore, we present our newly developed coupled plasma-surface kinetics model for DRM, to provide more insight in the underlying reasons. Our model illustrates that transition metal catalysts can adversely affect plasmacatalytic DRM, if radicals dominate the plasma-catalyst interactions. Thus, we demonstrate that a good understanding of the plasma-catalyst interactions is crucial to avoiding conditions at which these interactions negatively affect the results, and we provide some recommendations for improvement. For instance, we believe that plasma-catalytic DRM may benefit more from higher reaction temperatures,at which vibrational excitation can enhance the surface reactions.
基金supported by the National Natural Science Foundation of China(21922304,22276086)the Fundamental Research Funds for the Central Universities。
文摘The synthesis of mesoporous zeolite-anchored atomically dispersed metal catalysts(ADCs)is a considerable challenge in chemistry and materials science.Here we report the synthesis of atomically dispersed cationic nickel-confined mesoporous ZSM-48(ANMZ-48)by in situ hydrothermal reaction employing a designed tri-functional metal complex template,by which the triquaternary ammonium groups in the hydrophilic region direct the formation of ZSM-48 zeolite;the aromatic groups in the hydrophobic tail generate the mesopores through π-π stacking;and the complexes formed by nickel ions coordinated with terpyridyl groups generate atomically dispersed Ni2+confined in zeolite frameworks due to the strong sintering resistance generated by the strong coordination interaction.The ANMZ-48 is consisting of stacking of sheet-like ZSM-48 domains connected by multiply crystal twinning sharing the common(011)plane,generating abundant of imbedded mesopores with the uniform thickness of~2.4 nm and with the width of 10-50 nm.The excellent catalytic activity and stability of ANMZ-48 were also reflected in the dry reforming of methane(DRM)reaction.
基金This work was financially supported by the Basic Science Center Program for Ordered Energy Conversion of the National Natural Science Foundation of China(51888103)the National Key R&D Program of China(2021YFF0500700)Jiangsu Natural Science Foundation Project(BE2022024 and BK20202008).
文摘Solar-driven CO_(2)-to-fuel conversion assisted by another major greenhouse gas CH_(4)is promising to concurrently tackle energy shortage and global warming problems.However,current techniques still suffer from drawbacks of low efficiency,poor stability,and low selectivity.Here,a novel nanocomposite composed of interconnected Ni/MgAlOx nanoflakes grown on SiO_(2)particles with excellent spatial confinement of active sites is proposed for direct solar-driven CO_(2)-to-fuel conversion.An ultrahigh light-to-fuel efficiency up to 35.7%,high production rates of H_(2)(136.6 mmol min^(-1)g^(-1))and CO(148.2 mmol min^(-1)g^(-1)),excellent selectivity(H_(2)/CO ratio of 0.92),and good stability are reported simultaneously.These outstanding performances are attributed to strong metal-support interactions,improved CO_(2)absorption and activation,and decreased apparent activation energy under direct light illumination.MgAlO_(x)@SiO_(2)support helps to lower the activation energy of CH^(*) oxidation to CHO^(*) and improve the dissociation of CH_(4)to CH_(3)^(*) as confirmed by DFT calculations.Moreover,the lattice oxygen of MgAlO_(x) participates in the reaction and contributes to the removal of carbon deposition.This work provides promising routes for the conversion of greenhouse gasses into industrially valuable syngas with high efficiency,high selectivity,and benign sustainability.
基金supported by the Natural Sciences and Engineering Research Council of Canada,the Discovery Grant(GRPIN-2016-05494)the Alberta Innovates Technology Futures Research Grant.
文摘The adverse effects of global warming and climate change have driven the exploration of feasible routes for CO_(2) capture,storage,conversion and utilization.The processes related to CO_(2) conversion in high-temperature electrochemical devices(HTEDs)using dense ceramic membranes are particularly appealing due to the simultaneous realization of highly efficient CO_(2) conversion and value-added chemical production as well as the generation of electricity and storage of renewable energy in some cases.Currently,most studies are focused on the two processes,CO_(2) electrolysis and H2O/CO_(2) co-electrolysis in oxygen-conducting solid oxide electrolysis cell(O-SOEC)reactors.Less attention has been paid to other meaningful CO_(2)-conversion-related processes in HTEDs and systematic summary and analysis are currently not available.This review will fill the gap and classify the CO_(2)-conversion-related processes in HTEDs reported in recent years into four types accord-ing to the related reactions,including assisted CO_(2) reduction to CO,H2O and CO_(2) co-conversion,dry reforming of methane and CO_(2) hydrogenation.Firstly,an overview of the fundamentals of HTED processes is presented,and then the related mechanism and research progress of each type of reactions in different HTEDs are elucidated and concluded accordingly.The remaining major technical issues are also briefly introduced.Lastly,the main challenges and feasible solutions as well as the future prospects of HTEDs for CO_(2)-conversion-related processes are also discussed in this review.
