The electrochemical coupling of biomass oxidation and nitrogen conversion presents a potential strategy for high value-added chemicals and nitrogen cycling.Herein,in this work,CuO/Co_(3)O_(4)with heterogeneous interfa...The electrochemical coupling of biomass oxidation and nitrogen conversion presents a potential strategy for high value-added chemicals and nitrogen cycling.Herein,in this work,CuO/Co_(3)O_(4)with heterogeneous interface is successfully constructed as a bifunctional catalyst for the electrooxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid and the electroreduction of nitrate to ammonia(NH_(3)).The open-circuit potential spontaneous experiment shows that more 5-hydroxymethylfurfural molecules are adsorbed in the Helmholtz layer of the CuO/Co_(3)O_(4)composite,which certifies that the CuO/Co_(3)O_(4)heterostructure is conducive to the kinetic adsorption of 5-hydroxymethylfurfural.In situ electrochemical impedance spectroscopy further shows that CuO/Co_(3)O_(4)has faster reaction kinetics and lower reaction potential in oxygen evolution reaction and 5-hydroxymethylfurfural electrocatalytic oxidation.Moreover,CuO/Co_(3)O_(4)also has a good reduction effect on NO_(3)^(-).The ex-situ Raman spectroscopy shows that under the reduction potential,the metal oxide is reduced,and the generated Cu_(2)O can be used as a new active site for the reaction to promote the electrocatalytic conversion of NO_(3)^(-)to NH_(3) synthesis.This work provides valuable guidance for the synthesis of value-added chemicals by 5-hydroxymethylfurfural electrocatalytic oxidation coupled with NO_(3)^(-)while efficiently producing NH_(3).展开更多
The development of highly effective metal-zeolite bifunctional catalysts for the hydroisomerization of n-alkanes is a paramount strategy to produce second-generation biofuels with high quality.In this study,polyhexame...The development of highly effective metal-zeolite bifunctional catalysts for the hydroisomerization of n-alkanes is a paramount strategy to produce second-generation biofuels with high quality.In this study,polyhexamethylene biguanide hydrochloride(PHMB)is precisely added to the initial gel to synthesize nanosized ZSM-23 zeolites(Z23-x PH).Due to orientation adsorption and steric hindrance effects of PHMB,each sample of Z23-x PH demonstrates enhanced mesoporosity in comparison with the conventional Z23-C zeolite.Furthermore,the Bronsted acid density of the Z23-x PH samples is also signifi cantly reduced due to a reduction in the distribution of framework Al at T2-T5 sites.The corresponding Pd/23-C and Pd/Z23-x PH bifunctional catalysts with 0.5 wt%Pd loading for n-hexadecane hydroisomerization are prepared by incorporating ZSM-23 zeolites as acid supports.According to the catalytic test results,the suitable addition of PHMB can effectively promote the iso-hexadecane yield.The Pd/Z23-2PH catalyst with an n_(PHMB)/n(_Si)molar ratio of 0.002 demonstrates the highest maximum iso-hexadecane yield of 74.1%at an n-hexadecane conversion of 88.3%.Therefore,the employment of PHMB has provided a simple route for the development of highly effective Pd/ZSM-23 catalysts for n-alkane hydroisomerization.展开更多
A series of ZnO-ZrO_(2) solid solutions with different Zn contents were synthesized by the urea coprecipitation method,which were coupled with H-ZSM-5 zeolite to form bifunctional catalysts.As a new benzene alkylation...A series of ZnO-ZrO_(2) solid solutions with different Zn contents were synthesized by the urea coprecipitation method,which were coupled with H-ZSM-5 zeolite to form bifunctional catalysts.As a new benzene alkylation reagent,syngas was used instead of methanol to realize the efficient conversion of syngas and benzene into toluene and xylene.A suitable ratio of ZnO-ZrO_(2) led to the significant improvement in the catalytic performance,and a suitable amount of acid helped to increase the selectivity of toluene/xylene and reduce the selectivity of the by-products ethylbenzene and C^(9+) aromatics.The highest benzene conversion of 89.2%and toluene/xylene selectivity of 88.7%were achieved over 10%ZnO-ZrO_(2)&H-ZSM-5(Si/Al=23)at a pressure of 3 MPa and a temperature of 450℃.In addition,the effect of the zeolite framework structure on product distribution was examined.Similar to the molecular dynamics of aromatic hydrocarbons,H-ZSM-5 zeolites comprise 10-membered-ring pores,which are beneficial to the activation of benzene;hence,the conversion of benzene is higher.H-ZSM-35 and HMOR zeolites exhibited small eight-membered-ring channels,which were not conducive to the passage of benzene;hence,the by-product ethylbenzene exhibits a higher selectivity.The distance between the active centers of the bifunctional catalysts was the main factor affecting the catalytic performance,and the powder mixing method was more conducive to the conversion of syngas and benzene.展开更多
The utilization of non-noble metal catalysts with robust and highly efficient electrocatalytic activity for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)are extremely important for the large-scale...The utilization of non-noble metal catalysts with robust and highly efficient electrocatalytic activity for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)are extremely important for the large-scale implementation of renewable energy devices.Integration of bifunctional electrocatalysts on both anode and cathode electrodes remains a significant challenge.Herein,we report on a novel and facile strategy to construct the ordered and aligned MoS_(2)nanosheet-encapsulated metal–organic frameworks(MOFs)derived hollow CoS polyhedron,in-situ grown on a nickel foam(NF).The starfish-like MoS_(2)/CoS/NF heterojunctions were formed due to the ordered growth of the material caused by NF substrate.The optimized 2-MoS_(2)/CoS/NF heterojunction exhibits robust bifunctional electrocatalytic activity with a low overpotential of 67 and 207 m V toward the HER and OER at 10 mA cm^(-2),and the long-term stability,which exceeds most of the reported bifunctional electrocatalysts.Such high electrocatalytic performance arises due to the synergistic effect between the MoS_(2)and CoS phases across the interface,the abundant active sites,as well as the hierarchical pore framework,which collectively enhance the mass and electron transfer during the reactions.The work provides a promising approach to fabricating bifunctional catalysts with custom-designed heterojunctions and remarkable performance for applications in electrochemical energy devices and related areas.展开更多
Zinc-air batteries(ZABs) with high energy density and safety are promising as next-generation energy storage systems, while their applications are severely hindered by the sluggish reaction kinetic of air cathodes. De...Zinc-air batteries(ZABs) with high energy density and safety are promising as next-generation energy storage systems, while their applications are severely hindered by the sluggish reaction kinetic of air cathodes. Developing a bifunctional catalyst with high activity and durability is an effective strategy to address the above challenges. Herein, a Co_(3)O_(4)/Mn_(3)O_(4) nanohybrid with heterointerfaces is designed as advanced cathode catalyst for ZABs. Density functional theory calculations show the heterogeneous interface between Co_(3)O_(4)/Mn_(3)O_(4) can improve the dynamics of carrier transport and thus enhancing the catalytic activity and durability. The Co_(3)O_(4)/Mn_(3)O_(4) catalyst anchored on reduced graphene oxide(rGO)exhibits high oxygen reduction reaction(ORR) activity with a half-wave potential of 0.86 V, and excellent oxygen evolution reaction(OER) activity with the potential of 1.59 V at 10 mA cm^(-2) , which are comparable to the commercial noble metal catalysts. The improved ORR/OER catalytic activity is ascribed to the synergistic effect of heterointerfaces between Co_(3)O_(4) and Mn_(3)O_(4)as well as the improved conductivity and contact area of oxygen/catalysts/electrolytes three-phase interface by r GO. Furthermore, a home-made ZAB based on Co_(3)O_(4)/Mn_(3)O_(4)/r GO shows a high open circuit voltage of 1.54 V, a large power density of 194.6 mW cm^(-2) and good long-term cycling stability of nearly 400 h at 5 mA cm^(-2) , which affords a promising bifunctional oxygen catalyst for rechargeable ZABs.展开更多
A series of Pd/MIL-53(Al) heterogeneous bifunctional catalysts with di erent Pd contents were prepared by an impregnation method. The prepared metal–organic frameworks MIL-53(Al) and catalysts were characterized by X...A series of Pd/MIL-53(Al) heterogeneous bifunctional catalysts with di erent Pd contents were prepared by an impregnation method. The prepared metal–organic frameworks MIL-53(Al) and catalysts were characterized by XRD, SEM, HRTEM,FT-IR and N2 adsorption/desorption techniques. The results showed that MIL-53(Al) was synthesized successfully, and the structure was unchanged during and after the preparation of the catalysts. The Pd nanoparticles(NPs) with an average particle size of 4.6 nm were uniformly dispersed on the MIL-53(Al). The catalyst exhibited good catalytic activity in the selective oxidation of liquid methanol to methyl formate. Under the conditions of 150 °C, 2 MPa O2 and solvent-free for5 h, the conversion of methanol could reach 60.3%, and the selectivity of methyl formate was up to 62.2%. In addition, the Pd/MIL-53(Al) bifunctional catalyst exhibited excellent stability and maintained high catalytic activity after five cycles.展开更多
Zinc-air batteries(ZABs)are widely studied because of their high theoretical energy density,high battery voltage,environmental protection,and low price.However,the slow kinetics of oxygen reduction reaction(ORR)and ox...Zinc-air batteries(ZABs)are widely studied because of their high theoretical energy density,high battery voltage,environmental protection,and low price.However,the slow kinetics of oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)on the air electrode limits the further application of ZABs,so that how to develop a cheap,efficient,and stable catalyst with bifunctional catalytic activity is the key to solving the development of ZABs.Transition metal compounds are widely used as cathode materials for ZABs due to their low cost,high electrocatalytic activity,and stable structure.This review summarizes the research progress of transition metal compounds as bifunctional catalysts for ZABs.The development history,operation principle,and mechanism of ORR and OER reactions are introduced first.The application and development of transition metal compounds as bifunctional catalysts for ZABs in recent years are systematically introduced,including transition metal oxides(TMOs),transition metal nitrides(TMNs),transition metal sulfides(TMSs),transition metal carbides(TMCs),transition metal phosphates(TMPs),and others.In addition,the shortcomings of transition metal compounds as bifunctional catalysts for ZABs were summarized and reasonable design strategies and improvement measures were put forward,aiming at providing a reference for the design and construction of high-performance ZABs cathode materials.Finally,the challenges and future in this field are discussed and prospected.展开更多
Bifunctional metal/zeolite materials are some of the most suitable catalysts for the direct hydroalkylation of benzene to cyclohexylbenzene.The overall catalytic performance of this reaction is strongly influenced by ...Bifunctional metal/zeolite materials are some of the most suitable catalysts for the direct hydroalkylation of benzene to cyclohexylbenzene.The overall catalytic performance of this reaction is strongly influenced by the hydrogenation,which is dependent on the metal sizes.Thus,systematically investigating the metal size effects in the hydroalkylation of benzene is essential.In this work,we successfully synthesized Ru and Pd nanoparticles on Sinopec Composition Materials No.1 zeolite with various metal sizes.We demonstrated the size-dependent catalytic activity of zeolite-supported Ru and Pd catalysts in the hydroalkylation of benzene,which can be attributed to the size-induced hydrogen spillover capability differences.Our work presents new insights into the hydroalkylation reaction and may open up a new avenue for the smart design of advanced metal/zeolite bi-functional catalysts.展开更多
Epoxidation is an important chemical process for the production of epoxides,key building blocks in chemical industry.Despite great efforts being made to facilitate this process,it remains a significant challenge to de...Epoxidation is an important chemical process for the production of epoxides,key building blocks in chemical industry.Despite great efforts being made to facilitate this process,it remains a significant challenge to develop cost-effective,environmental-friendly,and selective catalysts.Herein,we reported a highly dispersed Mn supported by g-C_(3)N_(4)(Mn/g-C_(3)N_(4))with Mn loading up to 2.56 wt%.The Mn/g-CN_(4)exhibited satisfied catalytic performance for olefin epoxidation with excellent conversion(91%),high selectivity(93%)as well as outstanding recycling stability.Further analysis revealed the importance of Mn-N structure for the generation of active oxo-containing species and subsequent oxygen atom transfer.Besides,an efficient synthesis of cyclic carbonates from styrene epoxide and CO_(2)has been achieved(88%conversion,89%selectivity)based on the polar Mn-N coordinated characteristics of Mn/g-C_(3)N_(4)catalyst.展开更多
Deep degradation of organic pollutants by sunlight-induced coupled photocatalytic and Fenton (photo-Fenton) reactions is of immense importance for water purification. In this work, we report a novel bifunctional catal...Deep degradation of organic pollutants by sunlight-induced coupled photocatalytic and Fenton (photo-Fenton) reactions is of immense importance for water purification. In this work, we report a novel bifunctional catalyst (Fe-PEI-CN) by codoping graphitic carbon nitride (CN) with polyethyleneimine ethoxylated (PEI) and Fe species, which demonstrated high activity during p-chlorophenol (p-ClPhOH) degradation via H_(2)O_(2) from the photocatalytic process. The relationship between the catalytic efficiency and the structure was explored using diff erent characterization methods. The Fe modification of CN was achieved through Fe-N coordination, which ensured high dispersion of Fe species and strong stability against leaching during liquid- phase reactions. The Fe modification initiated the Fenton reaction by activating H_(2)O_(2) into ·OH radicals for deep degradation of p-ClPhOH. In addition, it eff ectively promoted light absorption and photoelectron-hole (e-h ^(+) ) separation, corresponding to improved photocatalytic activity. On the other hand, PEI could significantly improve the ability of CN to generate H_(2)O_(2) through visible light photocatalysis. The maximum H_(2)O_(2) yield reached up to 102.6 μmol/L, which was 22 times higher than that of primitive CN. The cooperation of photocatalysis and the self-Fenton reaction has led to high-activity mineralizing organic pollutants with strong durability, indicating good potential for practical application in wastewater treatment.展开更多
Oxygen electrode catalysts are important as inter-conversion of O_(2) and H_(2)O is crucial for energy technologies.However,the sluggish kinetics of oxygen reduction and evolution reactions(ORR and OER)are a hindrance...Oxygen electrode catalysts are important as inter-conversion of O_(2) and H_(2)O is crucial for energy technologies.However,the sluggish kinetics of oxygen reduction and evolution reactions(ORR and OER)are a hindrance to their scalable production,whereas scarce and costly Pt and Ir/Ru-based catalysts with the highest electrocatalytic activity are commercially unviable.Since good ORR catalysts are not always efficient for OER and vice versa,so bifunctional catalysts on which OER and ORR occurs on the same electrode are very desirable.Alternative catalysts based on heteroatom-doped carbon nanomaterials,though showed good electrocatalytic activity yet their high cost and complex synthesis is not viable for scalable production.To overcome these drawbacks,biomass-derived heteroatom-doped porous carbons have recently emerged as low-cost,earth-abundant,renewable and sustainable environment-friendly materials for bifunctional oxygen catalysts.The tunable morphology,mesoporous structure and high concentration of catalytic active sites of these materials due to heteroatom(N)-doping could further enhance their ORR and OER activity,along with tolerance to methanol crossover and good durability.Thus,biomassderived heteroatom-doped porous carbons with large surface area,rich edge defects,numerous micropores and thin 2 D nanoarchitecture could be suitable as efficient bifunctional oxygen catalysts.In the present article,synthesis,N-doping,ORR/OER mechanism and electrocatalytic performance of biomassderived bifunctional catalysts has been discussed.The selected biomass(chitin,eggs,euonymus japonicas,tobacco,lysine and plant residue)except wood,act as both C and N precursor,resulting in N selfdoping of porous carbons that avoids the use of toxic chemicals,thus making the synthesis a facile and environment-friendly green process.The synthetic strategy could be further optimized to develop future biomass-based N self-doped porous carbons as metal-free high performance bifunctional oxygen catalysts for commercial energy applications.Recent advances and the importance of biomass-based bifunctional oxygen catalysts in metal-air batteries and fuel cells has been highlighted.The material design,perspectives and future directions in this field are also provided.展开更多
The development of bifunctional catalysts has drawn much attention in realizing efficient and feasible catalytic systems to meet the diverse dema nd of pote ntial industrial applications.Desig n of stable and powerful...The development of bifunctional catalysts has drawn much attention in realizing efficient and feasible catalytic systems to meet the diverse dema nd of pote ntial industrial applications.Desig n of stable and powerful bifun ctional catalysts for various catalysis systems is highly desirable yet largely unmet.Here,three kinds of decavanadate-based transition metal hybrids(DTMH)(i.e.,Co-DTMH,Ni-DTMH and Ag-DTMH)have been successfully synthesized through a pH tuning strategy and further characterized.Specifically,the rare M05N six-coordinated transition metal coordination modes have been detected in Co-DTMH and Ni-DTMH,while Ag atoms in Ag-DTMH exhibited three-and five-coordinated geometries with the tuning of specially selected imidazole ligands.Thus-obtained clusters can serve as powerful bifunctional catalysts for both sulfide oxidation and C-C bond construction.Remarkably,Ag-DTMH dem on st rated excellent heteroge ne ous bifunctional catalytic properties in the selective oxidati on of sulfides and construction of C-C bond(yields up to 99%),which enable successful recycling for three cycles with remained catalytic activities and structure stability.The newly designed decavanadate-based transition metal hybrids with bifunctional property hold high promise in the practical applications like continuous catalysis or flow bed reactions.展开更多
Hydrogen, serving as a clean, sustainable energy source, may be mainly produced from electrolysis water. Herein, we report cobalt disulphide encapsulated in self-catalyzed carbon nanotubes （S, N-CNTs/ CoS2@Co） servi...Hydrogen, serving as a clean, sustainable energy source, may be mainly produced from electrolysis water. Herein, we report cobalt disulphide encapsulated in self-catalyzed carbon nanotubes （S, N-CNTs/ CoS2@Co） serving as a bifunctional catalyst, which exhibits excellent hydrogen evolution reaction perfor-mance （10.0 mAcm^-2 at 0.112 V, and low Tafel slope for 104.9 mV dec^-1 ） and oxygen evolution reaction performance （10.0 mAcm^-2 at 1.57 V, and low Tafel slope for 76.1 mV dec^-1）, meanwbile with a strong stability at various current densities. In-depth study reveals that the excellent catalytic properties can be mainly attributed to the increased catalytic sites induced by S, N co-doping, the improved electronic con-ductivity derived from the carbon nanotubes, and Mott-Schottky effect between the metal cobalt and semiconductive cobalt disulfide. Notably, when the bifunctional catalysts are applied to overall water splitting, a low potential of 1.633 V at the current density of 10.0 mAcm^-2 is achieved, which can com-pete with the precious metal catalyst benchmarks in alkaline media, demonstrating its promising prac-ticability in the realistic water splitting application. This work elucidates a practicable way to the design of transition metal and nano-carbon composite catalysts for a broad application in the fields of energy chemistry.展开更多
A series of CuO-ZnO-Al2O3-La2O3/HZSM-5 biftmctional catalysts with various La loadings for dimethyl ether （DME） directly synthesized from CO2 hydrogenation were prepared. The catalysts were characterized with N2 ads...A series of CuO-ZnO-Al2O3-La2O3/HZSM-5 biftmctional catalysts with various La loadings for dimethyl ether （DME） directly synthesized from CO2 hydrogenation were prepared. The catalysts were characterized with N2 adsorption-desorption, X-ray diffraction （XRD）, H2 temperature-programmed reduction （H2-TPR）, NH3 temperature-programmed desorption （NH3-TPD） and N2O titration techniques, and tested for the synthesis of DME directly from CO2 hydrogenation in a fixed-bed reactor. The results showed that the reducibility, dispersion ofbifunctional catalysts were strongly dependent on the addition of La. With the addition of appropri- ate amount of La, the crystaUite size of CuO was decreased and the dispersion of Cu on the surface was enhanced, which resulted in the increased conversion of CO2. It was also found that the selectivity to DME was related to the intensity and amount of strong acid site on the catalyst surface. The presence of La favored the production of DME, and the optimum catalytic activity was obtained when the amount of La was 2.0 wt.%.展开更多
Catalysts for oxygen and hydrogen evolution reactions （OER/HER） are at the heart of renewable green energy sources such as water splitting. Although incredible efforts have been made to develop efficient catalysts f...Catalysts for oxygen and hydrogen evolution reactions （OER/HER） are at the heart of renewable green energy sources such as water splitting. Although incredible efforts have been made to develop efficient catalysts for OER and HER, great challenges still remain in the development of bifunctional catalysts. Here, we report a novel hybrid of Co3O4 embedded in tubular nanostructures of graphitic carbon nitride （GCN） and synthesized through a facile, large-scale chemical method at low temperature. Strong synergistic effects between Co3O4 and GCN resulted in excellent performance as a bifunctional catalyst for OER and HER. The high surface area, unique tubular nanostructure, and composition of the hybrid made all redox sites easily available for catalysis and provided faster ionic and electronic conduction. The Co3O4@GCN tubular nanostructured （TNS） hybrid exhibited the lowest overpotential （0.12 V） and excellent current density （147 mA/cm^2） in OER, better than benchmarks IrO2 and RuO2, and with superior durability in alkaline media. Furthermore, the Co3O4@GCN TNS hybrid demonstrated excellent performance in HER, with a much lower onset and overpotential, and a stable current density. It is expected that the Co3O4@GCN TNS hybrid developed in this study will be an attractive alternative to noble metals catalysts in large scale water splitting and fuel cells.展开更多
Integrating two different catalytic active sites into one composite is a useful 2-in-1 strategy for designing high-efficient bifunctional catalysts,which can easily tailor the activity of each reaction.Hence,we adopt ...Integrating two different catalytic active sites into one composite is a useful 2-in-1 strategy for designing high-efficient bifunctional catalysts,which can easily tailor the activity of each reaction.Hence,we adopt the 2-in-1 strategy to design the metal oxyhydroxide supported on N-doped porous carbons(PA-CoFe@NPC)as the oxygen bifunctional catalyst,where NPC provides the activity for oxygen reduction reaction(ORR)while the metal oxyhydroxide is responsible for oxygen evolution reaction(OER).Results demonstrate that the PA-CoFe@NPC indeed exhibits both super ORR and OER activities.Impressively,using bifunctional PA-CoFe@NPC as the oxygen electrode,the resulting Zn-air battery exhibits outstanding charge and discharge performance with the peak power density of 156.3 mW cm^(-2),and also exhibits a long-term cycle stability with continuous cyclic charge and discharge of 170 hours that is obviously better than the 20%Pt/C+IrO_(2)based one.The 2-in-1 strategy in this work can be efficiently extended to design other bi-or multi-functional electrocatalysts.展开更多
Toluene methylation with methanol on H‐ZSM‐5(Z5)zeolite for the directional transformation of toluene to xylene has been industrialized.However,great challenges remain because of the high energy barrier of methanol ...Toluene methylation with methanol on H‐ZSM‐5(Z5)zeolite for the directional transformation of toluene to xylene has been industrialized.However,great challenges remain because of the high energy barrier of methanol deprotonation to the methoxy group,the side reaction of methanol to olefins,coke formation,and the deactivation of zeolites.Herein,we report the toluene methylation coupled with CO hydrogenation to showcase an enhancement in para‐xylene(PX)selectivity by employing a bifunctional catalyst composed of ZnZrO_(x)(ZZO)and modified Z5.The results showed that a PX selectivity of up to 81.8%in xylene and xylene selectivity of 64.8%in hydrocarbons at 10.3%toluene conversion can be realized over the bifunctional catalyst on a fixed‐bed reactor.The selectivity of gaseous hydrocarbons decreased to 10.9%,and approximately half of that was observed in methanol reagent route where the PX selectivity in xylene was 38.8%.We observed that the acid strength,the quantity ratio of Brönsted and Lewis acid sites,and the pore size of zeolites were essential for the PX selectivity.The investigation of the H_(2)/D_(2) kinetic isotope effect revealed that the newborn methyl group in xylene resulted from the hydrogenation of CO rather than toluene disproportionation.Furthermore,the catalyst showed no evident deactivation within the 100 h stability test.The findings offer a promising route for the production of value‐added PX with high selectivity via toluene methylation coupled with syngas conversion.展开更多
In the field of electrolysis of water,the design and synthesis of catalysts over a wide pH range have attracted extensive attentions.In this paper,Co and N are co-introduced into the structural unit of tungsten disulf...In the field of electrolysis of water,the design and synthesis of catalysts over a wide pH range have attracted extensive attentions.In this paper,Co and N are co-introduced into the structural unit of tungsten disulfide(WS_(2)),and the hydrogen evolution reaction(HER)performances of different WS_(2)-based catalysts are theoretically predicted and systematically studied by density functional theory(DFT)calculations.With the guidance of DFT calculations,an evaporation-pyrolysis strategy is applied to prepare Co and N co-doped WS_(2)(Co,N-WS_(2))flower-like nanosheets,which exhibits excellent HER performance over a wide pH range.In addition,the DFT calculations show that the active sites in Co,N-WS_(2) have a good ability of hydrogen adsorption after the introduction of Co and N,suggesting that such a co-doping system will be an ideal catalyst for oxidative dehydrogenation(ODH).The following experiment results indeed evidence that the Co,N-WS_(2) catalyst displays a high activity in the ODH of 1,2,3,4-tetrahydroquinoline(4H-quinoline)and its derivatives.Therefore,this work provides a good example for the rational design and accurate preparation of functional catalysts,which enables it possible to develop other efficient catalysts with multiple functions.展开更多
Bifunctional TiO2 photocatalysts co-doped with nitrogen and sulfur were prepared by the controlled thermal decomposition of ammonium titanyl sulfate precursor. They have both photocatalytic activity and Brφnsted acid...Bifunctional TiO2 photocatalysts co-doped with nitrogen and sulfur were prepared by the controlled thermal decomposition of ammonium titanyl sulfate precursor. They have both photocatalytic activity and Brφnsted acidity, and thus are active in the photoreduction of Cr（VI） under solar light irradiation without the addition of acids. The activity is superior to that of Degussa P25 in the acidified suspension at the same pH adjusted by H2SO4.展开更多
Novel organic-inorganic hybrids were synthesized by using HfCl 4 and organic ligand 1H-pyrrole-2,5-dicarboxylic acid(PDCA)via a simple hydrothermal method.The as-prepared Hf-PDCA were characterized by various techniqu...Novel organic-inorganic hybrids were synthesized by using HfCl 4 and organic ligand 1H-pyrrole-2,5-dicarboxylic acid(PDCA)via a simple hydrothermal method.The as-prepared Hf-PDCA were characterized by various techniques,such as electron microscope,N_(2) adsorption/desorption,and X-ray photoelectron spectroscopy.Among them,the porous and nitrogen-containing Hf-PDCA as heterogeneous acid/base bifunctional catalyst was then applied to the catalytic hydrogenation of furfural to produce furfuryl alcohol(FFA).It exhibited excellent catalytic performance,with high conversion(98.8%)and selectivity(98.5%)by using 2-propanol as hydrogen source under a relatively mild condition.Moreover,the Hf-PDCA has strong stability and durability,and can be recovered after the catalyst reaction.In addition,the Hf-PDCA as catalyst can be extended to fabricate corresponding alcohols by catalytic conversion of other biomass derived aldehydes.展开更多
基金the support received from the National Natural Science Foundation of China(Grant No.22372012,22261160640,and 22002009)the Natural Science Foundation of Hunan Province(Grant No.2023JJ20037 and 2021JJ40565)the Scientific Research Project of Hunan Provincial Department of Education(Grant No.22B0293)
文摘The electrochemical coupling of biomass oxidation and nitrogen conversion presents a potential strategy for high value-added chemicals and nitrogen cycling.Herein,in this work,CuO/Co_(3)O_(4)with heterogeneous interface is successfully constructed as a bifunctional catalyst for the electrooxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid and the electroreduction of nitrate to ammonia(NH_(3)).The open-circuit potential spontaneous experiment shows that more 5-hydroxymethylfurfural molecules are adsorbed in the Helmholtz layer of the CuO/Co_(3)O_(4)composite,which certifies that the CuO/Co_(3)O_(4)heterostructure is conducive to the kinetic adsorption of 5-hydroxymethylfurfural.In situ electrochemical impedance spectroscopy further shows that CuO/Co_(3)O_(4)has faster reaction kinetics and lower reaction potential in oxygen evolution reaction and 5-hydroxymethylfurfural electrocatalytic oxidation.Moreover,CuO/Co_(3)O_(4)also has a good reduction effect on NO_(3)^(-).The ex-situ Raman spectroscopy shows that under the reduction potential,the metal oxide is reduced,and the generated Cu_(2)O can be used as a new active site for the reaction to promote the electrocatalytic conversion of NO_(3)^(-)to NH_(3) synthesis.This work provides valuable guidance for the synthesis of value-added chemicals by 5-hydroxymethylfurfural electrocatalytic oxidation coupled with NO_(3)^(-)while efficiently producing NH_(3).
基金funded by the National Key Research and Development Project,Intergovernmental International Science and Technology Innovation Cooperation Key Project(No.2018YFE0108800)National Natural Science Foundation of China(No.22278115)Heilongjiang Province Natural Science Foundation(No.YQ2021B010).
文摘The development of highly effective metal-zeolite bifunctional catalysts for the hydroisomerization of n-alkanes is a paramount strategy to produce second-generation biofuels with high quality.In this study,polyhexamethylene biguanide hydrochloride(PHMB)is precisely added to the initial gel to synthesize nanosized ZSM-23 zeolites(Z23-x PH).Due to orientation adsorption and steric hindrance effects of PHMB,each sample of Z23-x PH demonstrates enhanced mesoporosity in comparison with the conventional Z23-C zeolite.Furthermore,the Bronsted acid density of the Z23-x PH samples is also signifi cantly reduced due to a reduction in the distribution of framework Al at T2-T5 sites.The corresponding Pd/23-C and Pd/Z23-x PH bifunctional catalysts with 0.5 wt%Pd loading for n-hexadecane hydroisomerization are prepared by incorporating ZSM-23 zeolites as acid supports.According to the catalytic test results,the suitable addition of PHMB can effectively promote the iso-hexadecane yield.The Pd/Z23-2PH catalyst with an n_(PHMB)/n(_Si)molar ratio of 0.002 demonstrates the highest maximum iso-hexadecane yield of 74.1%at an n-hexadecane conversion of 88.3%.Therefore,the employment of PHMB has provided a simple route for the development of highly effective Pd/ZSM-23 catalysts for n-alkane hydroisomerization.
基金financial support from the National Key Research&Development Program of China(2018YFB0604901)the National Natural Science Foundation of China(21706210)the Key Research&Development Program of Shaanxi Province(2020ZDLGY11-06)。
文摘A series of ZnO-ZrO_(2) solid solutions with different Zn contents were synthesized by the urea coprecipitation method,which were coupled with H-ZSM-5 zeolite to form bifunctional catalysts.As a new benzene alkylation reagent,syngas was used instead of methanol to realize the efficient conversion of syngas and benzene into toluene and xylene.A suitable ratio of ZnO-ZrO_(2) led to the significant improvement in the catalytic performance,and a suitable amount of acid helped to increase the selectivity of toluene/xylene and reduce the selectivity of the by-products ethylbenzene and C^(9+) aromatics.The highest benzene conversion of 89.2%and toluene/xylene selectivity of 88.7%were achieved over 10%ZnO-ZrO_(2)&H-ZSM-5(Si/Al=23)at a pressure of 3 MPa and a temperature of 450℃.In addition,the effect of the zeolite framework structure on product distribution was examined.Similar to the molecular dynamics of aromatic hydrocarbons,H-ZSM-5 zeolites comprise 10-membered-ring pores,which are beneficial to the activation of benzene;hence,the conversion of benzene is higher.H-ZSM-35 and HMOR zeolites exhibited small eight-membered-ring channels,which were not conducive to the passage of benzene;hence,the by-product ethylbenzene exhibits a higher selectivity.The distance between the active centers of the bifunctional catalysts was the main factor affecting the catalytic performance,and the powder mixing method was more conducive to the conversion of syngas and benzene.
基金the financial support from the National Natural Science Foundation of China(22005273,21825106 and 21671175)the Natural Science Foundation of Henan Province(222300420258)+3 种基金the Scientific and Technological Research Project in Henan Province(222102240065 and 212102210647)the Key scientific research projects of colleges and universities in Henan Province(No.22A530006)the Natural Science Foundation of Jiangsu Province(BK20220598)the Program for Science&Technology Innovative Research Team in University of Henan Province(20IRTSTHN007)。
文摘The utilization of non-noble metal catalysts with robust and highly efficient electrocatalytic activity for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)are extremely important for the large-scale implementation of renewable energy devices.Integration of bifunctional electrocatalysts on both anode and cathode electrodes remains a significant challenge.Herein,we report on a novel and facile strategy to construct the ordered and aligned MoS_(2)nanosheet-encapsulated metal–organic frameworks(MOFs)derived hollow CoS polyhedron,in-situ grown on a nickel foam(NF).The starfish-like MoS_(2)/CoS/NF heterojunctions were formed due to the ordered growth of the material caused by NF substrate.The optimized 2-MoS_(2)/CoS/NF heterojunction exhibits robust bifunctional electrocatalytic activity with a low overpotential of 67 and 207 m V toward the HER and OER at 10 mA cm^(-2),and the long-term stability,which exceeds most of the reported bifunctional electrocatalysts.Such high electrocatalytic performance arises due to the synergistic effect between the MoS_(2)and CoS phases across the interface,the abundant active sites,as well as the hierarchical pore framework,which collectively enhance the mass and electron transfer during the reactions.The work provides a promising approach to fabricating bifunctional catalysts with custom-designed heterojunctions and remarkable performance for applications in electrochemical energy devices and related areas.
基金support from the National Key Research and Development Program of China (2019YFA0705700)the National Natural Science Foundation of China (52072205)+1 种基金the start-up funds of Tsinghua Shenzhen International Graduate Schoosupported by the China Postdoctoral Science Foundation(2020M680542)。
文摘Zinc-air batteries(ZABs) with high energy density and safety are promising as next-generation energy storage systems, while their applications are severely hindered by the sluggish reaction kinetic of air cathodes. Developing a bifunctional catalyst with high activity and durability is an effective strategy to address the above challenges. Herein, a Co_(3)O_(4)/Mn_(3)O_(4) nanohybrid with heterointerfaces is designed as advanced cathode catalyst for ZABs. Density functional theory calculations show the heterogeneous interface between Co_(3)O_(4)/Mn_(3)O_(4) can improve the dynamics of carrier transport and thus enhancing the catalytic activity and durability. The Co_(3)O_(4)/Mn_(3)O_(4) catalyst anchored on reduced graphene oxide(rGO)exhibits high oxygen reduction reaction(ORR) activity with a half-wave potential of 0.86 V, and excellent oxygen evolution reaction(OER) activity with the potential of 1.59 V at 10 mA cm^(-2) , which are comparable to the commercial noble metal catalysts. The improved ORR/OER catalytic activity is ascribed to the synergistic effect of heterointerfaces between Co_(3)O_(4) and Mn_(3)O_(4)as well as the improved conductivity and contact area of oxygen/catalysts/electrolytes three-phase interface by r GO. Furthermore, a home-made ZAB based on Co_(3)O_(4)/Mn_(3)O_(4)/r GO shows a high open circuit voltage of 1.54 V, a large power density of 194.6 mW cm^(-2) and good long-term cycling stability of nearly 400 h at 5 mA cm^(-2) , which affords a promising bifunctional oxygen catalyst for rechargeable ZABs.
基金Financial support received from the National Natural Science Foundation of China(Grant Nos.21573015,21872004)
文摘A series of Pd/MIL-53(Al) heterogeneous bifunctional catalysts with di erent Pd contents were prepared by an impregnation method. The prepared metal–organic frameworks MIL-53(Al) and catalysts were characterized by XRD, SEM, HRTEM,FT-IR and N2 adsorption/desorption techniques. The results showed that MIL-53(Al) was synthesized successfully, and the structure was unchanged during and after the preparation of the catalysts. The Pd nanoparticles(NPs) with an average particle size of 4.6 nm were uniformly dispersed on the MIL-53(Al). The catalyst exhibited good catalytic activity in the selective oxidation of liquid methanol to methyl formate. Under the conditions of 150 °C, 2 MPa O2 and solvent-free for5 h, the conversion of methanol could reach 60.3%, and the selectivity of methyl formate was up to 62.2%. In addition, the Pd/MIL-53(Al) bifunctional catalyst exhibited excellent stability and maintained high catalytic activity after five cycles.
基金the German Research Foundation(DFG:LE 2249/15-1)the Sino-German Center for Research Promotion(GZ1579)Y.R.and C.F.X.would like to appreciate the support from the China Scholarship Council(Nos.202207030010 and 20210637004).
文摘Zinc-air batteries(ZABs)are widely studied because of their high theoretical energy density,high battery voltage,environmental protection,and low price.However,the slow kinetics of oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)on the air electrode limits the further application of ZABs,so that how to develop a cheap,efficient,and stable catalyst with bifunctional catalytic activity is the key to solving the development of ZABs.Transition metal compounds are widely used as cathode materials for ZABs due to their low cost,high electrocatalytic activity,and stable structure.This review summarizes the research progress of transition metal compounds as bifunctional catalysts for ZABs.The development history,operation principle,and mechanism of ORR and OER reactions are introduced first.The application and development of transition metal compounds as bifunctional catalysts for ZABs in recent years are systematically introduced,including transition metal oxides(TMOs),transition metal nitrides(TMNs),transition metal sulfides(TMSs),transition metal carbides(TMCs),transition metal phosphates(TMPs),and others.In addition,the shortcomings of transition metal compounds as bifunctional catalysts for ZABs were summarized and reasonable design strategies and improvement measures were put forward,aiming at providing a reference for the design and construction of high-performance ZABs cathode materials.Finally,the challenges and future in this field are discussed and prospected.
基金supported by China Petrochemical Corporation and the National Natural Science Foundation of China(Grant Nos.U19B6002,21972168,and 22302234).
文摘Bifunctional metal/zeolite materials are some of the most suitable catalysts for the direct hydroalkylation of benzene to cyclohexylbenzene.The overall catalytic performance of this reaction is strongly influenced by the hydrogenation,which is dependent on the metal sizes.Thus,systematically investigating the metal size effects in the hydroalkylation of benzene is essential.In this work,we successfully synthesized Ru and Pd nanoparticles on Sinopec Composition Materials No.1 zeolite with various metal sizes.We demonstrated the size-dependent catalytic activity of zeolite-supported Ru and Pd catalysts in the hydroalkylation of benzene,which can be attributed to the size-induced hydrogen spillover capability differences.Our work presents new insights into the hydroalkylation reaction and may open up a new avenue for the smart design of advanced metal/zeolite bi-functional catalysts.
基金financial supports from the National Natural Science Foundation of China(Nos.216330133and 22102197)Jiangsu Province Natural Science Foundation(No.BK20211096)the Science Fund of Shandong Laboratory of Advanced Materials and Green Manufacturing(Yantai,No.AMGM2021F07).
文摘Epoxidation is an important chemical process for the production of epoxides,key building blocks in chemical industry.Despite great efforts being made to facilitate this process,it remains a significant challenge to develop cost-effective,environmental-friendly,and selective catalysts.Herein,we reported a highly dispersed Mn supported by g-C_(3)N_(4)(Mn/g-C_(3)N_(4))with Mn loading up to 2.56 wt%.The Mn/g-CN_(4)exhibited satisfied catalytic performance for olefin epoxidation with excellent conversion(91%),high selectivity(93%)as well as outstanding recycling stability.Further analysis revealed the importance of Mn-N structure for the generation of active oxo-containing species and subsequent oxygen atom transfer.Besides,an efficient synthesis of cyclic carbonates from styrene epoxide and CO_(2)has been achieved(88%conversion,89%selectivity)based on the polar Mn-N coordinated characteristics of Mn/g-C_(3)N_(4)catalyst.
基金the National Key Research and Development Program of China (No. 2020YFA0211004)Key Grant of Nation Science Funding of China (No. 22236005)+5 种基金Nation Science Funding of China (No. 22376141)Ministry of Education of China (No. PCSIRT_IRT_16R49)“111” Innovation and Talent Recruitment Base (D18020)Shanghai Government (No. 20ZR1440700)Shanghai Engineering Research Center of Green Energy Chemical Engineering (No. 18DZ2254200)Scientific and Technological Innovation Team for Green Catalysis and Energy Materialien Yunnan Institutions of Higher Learning, and Surface project of Yunnan Province science and technology Department (No. 20210 A070001-050).
文摘Deep degradation of organic pollutants by sunlight-induced coupled photocatalytic and Fenton (photo-Fenton) reactions is of immense importance for water purification. In this work, we report a novel bifunctional catalyst (Fe-PEI-CN) by codoping graphitic carbon nitride (CN) with polyethyleneimine ethoxylated (PEI) and Fe species, which demonstrated high activity during p-chlorophenol (p-ClPhOH) degradation via H_(2)O_(2) from the photocatalytic process. The relationship between the catalytic efficiency and the structure was explored using diff erent characterization methods. The Fe modification of CN was achieved through Fe-N coordination, which ensured high dispersion of Fe species and strong stability against leaching during liquid- phase reactions. The Fe modification initiated the Fenton reaction by activating H_(2)O_(2) into ·OH radicals for deep degradation of p-ClPhOH. In addition, it eff ectively promoted light absorption and photoelectron-hole (e-h ^(+) ) separation, corresponding to improved photocatalytic activity. On the other hand, PEI could significantly improve the ability of CN to generate H_(2)O_(2) through visible light photocatalysis. The maximum H_(2)O_(2) yield reached up to 102.6 μmol/L, which was 22 times higher than that of primitive CN. The cooperation of photocatalysis and the self-Fenton reaction has led to high-activity mineralizing organic pollutants with strong durability, indicating good potential for practical application in wastewater treatment.
基金supported in part by Brain Pool Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (2019H1D3A2A02102086)the Hydrogen Energy Innovation Technology Development Program of the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT, & Future Planning (2019M3E6A1063677)。
文摘Oxygen electrode catalysts are important as inter-conversion of O_(2) and H_(2)O is crucial for energy technologies.However,the sluggish kinetics of oxygen reduction and evolution reactions(ORR and OER)are a hindrance to their scalable production,whereas scarce and costly Pt and Ir/Ru-based catalysts with the highest electrocatalytic activity are commercially unviable.Since good ORR catalysts are not always efficient for OER and vice versa,so bifunctional catalysts on which OER and ORR occurs on the same electrode are very desirable.Alternative catalysts based on heteroatom-doped carbon nanomaterials,though showed good electrocatalytic activity yet their high cost and complex synthesis is not viable for scalable production.To overcome these drawbacks,biomass-derived heteroatom-doped porous carbons have recently emerged as low-cost,earth-abundant,renewable and sustainable environment-friendly materials for bifunctional oxygen catalysts.The tunable morphology,mesoporous structure and high concentration of catalytic active sites of these materials due to heteroatom(N)-doping could further enhance their ORR and OER activity,along with tolerance to methanol crossover and good durability.Thus,biomassderived heteroatom-doped porous carbons with large surface area,rich edge defects,numerous micropores and thin 2 D nanoarchitecture could be suitable as efficient bifunctional oxygen catalysts.In the present article,synthesis,N-doping,ORR/OER mechanism and electrocatalytic performance of biomassderived bifunctional catalysts has been discussed.The selected biomass(chitin,eggs,euonymus japonicas,tobacco,lysine and plant residue)except wood,act as both C and N precursor,resulting in N selfdoping of porous carbons that avoids the use of toxic chemicals,thus making the synthesis a facile and environment-friendly green process.The synthetic strategy could be further optimized to develop future biomass-based N self-doped porous carbons as metal-free high performance bifunctional oxygen catalysts for commercial energy applications.Recent advances and the importance of biomass-based bifunctional oxygen catalysts in metal-air batteries and fuel cells has been highlighted.The material design,perspectives and future directions in this field are also provided.
基金supported by the National Natural Science Foundation of China(Nos.21871125 and 21901122)the Natural Science Foundation of Shandong Province,China(Nos.ZR2019MB043 and ZR2019QB022)+2 种基金the Construction Project of Quality Curriculum for Postgraduate Education of Shandong Province(No.SDYKC19057)the Natural Science Research of Jiangsu Higher Education Institutions of China(No.19KJB150011)Project funded by China Postdoctoral Science Foundation(No.2019M651873).
文摘The development of bifunctional catalysts has drawn much attention in realizing efficient and feasible catalytic systems to meet the diverse dema nd of pote ntial industrial applications.Desig n of stable and powerful bifun ctional catalysts for various catalysis systems is highly desirable yet largely unmet.Here,three kinds of decavanadate-based transition metal hybrids(DTMH)(i.e.,Co-DTMH,Ni-DTMH and Ag-DTMH)have been successfully synthesized through a pH tuning strategy and further characterized.Specifically,the rare M05N six-coordinated transition metal coordination modes have been detected in Co-DTMH and Ni-DTMH,while Ag atoms in Ag-DTMH exhibited three-and five-coordinated geometries with the tuning of specially selected imidazole ligands.Thus-obtained clusters can serve as powerful bifunctional catalysts for both sulfide oxidation and C-C bond construction.Remarkably,Ag-DTMH dem on st rated excellent heteroge ne ous bifunctional catalytic properties in the selective oxidati on of sulfides and construction of C-C bond(yields up to 99%),which enable successful recycling for three cycles with remained catalytic activities and structure stability.The newly designed decavanadate-based transition metal hybrids with bifunctional property hold high promise in the practical applications like continuous catalysis or flow bed reactions.
基金financially supported by the National Natural Science Foundation of China(21576056 and 21576057)Guangdong Natural Science Foundation(2017A030311016)+4 种基金Major Scientific Project of Guangdong University(2017KZDXM059)Science and Technology Research Project of Guangdong Province(2016A010103043)Science and Technology Research Project of Guangzhou(201607010232)Guangzhou University’s 2017 Training Program for Young Top-Notch Personnel(BJ201704)Australian Research Council(ARC)through Discovery Early Career Researcher Award(DE150101306)and Linkage Project(LP160100927)
文摘Hydrogen, serving as a clean, sustainable energy source, may be mainly produced from electrolysis water. Herein, we report cobalt disulphide encapsulated in self-catalyzed carbon nanotubes （S, N-CNTs/ CoS2@Co） serving as a bifunctional catalyst, which exhibits excellent hydrogen evolution reaction perfor-mance （10.0 mAcm^-2 at 0.112 V, and low Tafel slope for 104.9 mV dec^-1 ） and oxygen evolution reaction performance （10.0 mAcm^-2 at 1.57 V, and low Tafel slope for 76.1 mV dec^-1）, meanwbile with a strong stability at various current densities. In-depth study reveals that the excellent catalytic properties can be mainly attributed to the increased catalytic sites induced by S, N co-doping, the improved electronic con-ductivity derived from the carbon nanotubes, and Mott-Schottky effect between the metal cobalt and semiconductive cobalt disulfide. Notably, when the bifunctional catalysts are applied to overall water splitting, a low potential of 1.633 V at the current density of 10.0 mAcm^-2 is achieved, which can com-pete with the precious metal catalyst benchmarks in alkaline media, demonstrating its promising prac-ticability in the realistic water splitting application. This work elucidates a practicable way to the design of transition metal and nano-carbon composite catalysts for a broad application in the fields of energy chemistry.
基金supported by the National Key Technologies R&D Program of China(2011BAC01B03)the Natural Science Foundation of Yunnan Province(2013FZ035)support by Kunming University of Science and Technology through the Fund for Testingand Analyzing(No.2010213)
文摘A series of CuO-ZnO-Al2O3-La2O3/HZSM-5 biftmctional catalysts with various La loadings for dimethyl ether （DME） directly synthesized from CO2 hydrogenation were prepared. The catalysts were characterized with N2 adsorption-desorption, X-ray diffraction （XRD）, H2 temperature-programmed reduction （H2-TPR）, NH3 temperature-programmed desorption （NH3-TPD） and N2O titration techniques, and tested for the synthesis of DME directly from CO2 hydrogenation in a fixed-bed reactor. The results showed that the reducibility, dispersion ofbifunctional catalysts were strongly dependent on the addition of La. With the addition of appropri- ate amount of La, the crystaUite size of CuO was decreased and the dispersion of Cu on the surface was enhanced, which resulted in the increased conversion of CO2. It was also found that the selectivity to DME was related to the intensity and amount of strong acid site on the catalyst surface. The presence of La favored the production of DME, and the optimum catalytic activity was obtained when the amount of La was 2.0 wt.%.
基金Acknowledgements Work at Beijing Institute of Technology was supported by the National Natural Science Foundation of China （Nos. 23171023 and 50972017） and Doctoral Program of the Ministry of Education of China （No. 20101101110026） Work at Peking University was supported by the NSFC-RGC Joint Research Scheme （No. 51361165201）, the National Natural Science Foundation of China （Nos. 51125001 and 51172005）, Beijing Natural Science Foundation （No. 2122022） and Doctoral Program of the Ministry of Education of China （No. 20120001110078）. Deanship of Scientific Research at King Saud University through Prolific Research Group Project （No. PRG-1436-25）.
文摘Catalysts for oxygen and hydrogen evolution reactions （OER/HER） are at the heart of renewable green energy sources such as water splitting. Although incredible efforts have been made to develop efficient catalysts for OER and HER, great challenges still remain in the development of bifunctional catalysts. Here, we report a novel hybrid of Co3O4 embedded in tubular nanostructures of graphitic carbon nitride （GCN） and synthesized through a facile, large-scale chemical method at low temperature. Strong synergistic effects between Co3O4 and GCN resulted in excellent performance as a bifunctional catalyst for OER and HER. The high surface area, unique tubular nanostructure, and composition of the hybrid made all redox sites easily available for catalysis and provided faster ionic and electronic conduction. The Co3O4@GCN tubular nanostructured （TNS） hybrid exhibited the lowest overpotential （0.12 V） and excellent current density （147 mA/cm^2） in OER, better than benchmarks IrO2 and RuO2, and with superior durability in alkaline media. Furthermore, the Co3O4@GCN TNS hybrid demonstrated excellent performance in HER, with a much lower onset and overpotential, and a stable current density. It is expected that the Co3O4@GCN TNS hybrid developed in this study will be an attractive alternative to noble metals catalysts in large scale water splitting and fuel cells.
文摘Integrating two different catalytic active sites into one composite is a useful 2-in-1 strategy for designing high-efficient bifunctional catalysts,which can easily tailor the activity of each reaction.Hence,we adopt the 2-in-1 strategy to design the metal oxyhydroxide supported on N-doped porous carbons(PA-CoFe@NPC)as the oxygen bifunctional catalyst,where NPC provides the activity for oxygen reduction reaction(ORR)while the metal oxyhydroxide is responsible for oxygen evolution reaction(OER).Results demonstrate that the PA-CoFe@NPC indeed exhibits both super ORR and OER activities.Impressively,using bifunctional PA-CoFe@NPC as the oxygen electrode,the resulting Zn-air battery exhibits outstanding charge and discharge performance with the peak power density of 156.3 mW cm^(-2),and also exhibits a long-term cycle stability with continuous cyclic charge and discharge of 170 hours that is obviously better than the 20%Pt/C+IrO_(2)based one.The 2-in-1 strategy in this work can be efficiently extended to design other bi-or multi-functional electrocatalysts.
文摘Toluene methylation with methanol on H‐ZSM‐5(Z5)zeolite for the directional transformation of toluene to xylene has been industrialized.However,great challenges remain because of the high energy barrier of methanol deprotonation to the methoxy group,the side reaction of methanol to olefins,coke formation,and the deactivation of zeolites.Herein,we report the toluene methylation coupled with CO hydrogenation to showcase an enhancement in para‐xylene(PX)selectivity by employing a bifunctional catalyst composed of ZnZrO_(x)(ZZO)and modified Z5.The results showed that a PX selectivity of up to 81.8%in xylene and xylene selectivity of 64.8%in hydrocarbons at 10.3%toluene conversion can be realized over the bifunctional catalyst on a fixed‐bed reactor.The selectivity of gaseous hydrocarbons decreased to 10.9%,and approximately half of that was observed in methanol reagent route where the PX selectivity in xylene was 38.8%.We observed that the acid strength,the quantity ratio of Brönsted and Lewis acid sites,and the pore size of zeolites were essential for the PX selectivity.The investigation of the H_(2)/D_(2) kinetic isotope effect revealed that the newborn methyl group in xylene resulted from the hydrogenation of CO rather than toluene disproportionation.Furthermore,the catalyst showed no evident deactivation within the 100 h stability test.The findings offer a promising route for the production of value‐added PX with high selectivity via toluene methylation coupled with syngas conversion.
基金the National Natural Science Foundation of China(Nos.21771003,51902003,and 21501004)the University Synergy Innovation Program of Anhui Province(No.GXXT-2021-020)+1 种基金the Natural Science Foundation of Anhui Province(No.2008085QB53)the Natural Science Research Project of Anhui Province Education Department(No.KJ2019A0581).
文摘In the field of electrolysis of water,the design and synthesis of catalysts over a wide pH range have attracted extensive attentions.In this paper,Co and N are co-introduced into the structural unit of tungsten disulfide(WS_(2)),and the hydrogen evolution reaction(HER)performances of different WS_(2)-based catalysts are theoretically predicted and systematically studied by density functional theory(DFT)calculations.With the guidance of DFT calculations,an evaporation-pyrolysis strategy is applied to prepare Co and N co-doped WS_(2)(Co,N-WS_(2))flower-like nanosheets,which exhibits excellent HER performance over a wide pH range.In addition,the DFT calculations show that the active sites in Co,N-WS_(2) have a good ability of hydrogen adsorption after the introduction of Co and N,suggesting that such a co-doping system will be an ideal catalyst for oxidative dehydrogenation(ODH).The following experiment results indeed evidence that the Co,N-WS_(2) catalyst displays a high activity in the ODH of 1,2,3,4-tetrahydroquinoline(4H-quinoline)and its derivatives.Therefore,this work provides a good example for the rational design and accurate preparation of functional catalysts,which enables it possible to develop other efficient catalysts with multiple functions.
文摘Bifunctional TiO2 photocatalysts co-doped with nitrogen and sulfur were prepared by the controlled thermal decomposition of ammonium titanyl sulfate precursor. They have both photocatalytic activity and Brφnsted acidity, and thus are active in the photoreduction of Cr（VI） under solar light irradiation without the addition of acids. The activity is superior to that of Degussa P25 in the acidified suspension at the same pH adjusted by H2SO4.
基金support for this work by National Natural Science Foundation of China(No.21774036,No.21805047)Guangdong Province Science Foundation(No.2017GC010429).
文摘Novel organic-inorganic hybrids were synthesized by using HfCl 4 and organic ligand 1H-pyrrole-2,5-dicarboxylic acid(PDCA)via a simple hydrothermal method.The as-prepared Hf-PDCA were characterized by various techniques,such as electron microscope,N_(2) adsorption/desorption,and X-ray photoelectron spectroscopy.Among them,the porous and nitrogen-containing Hf-PDCA as heterogeneous acid/base bifunctional catalyst was then applied to the catalytic hydrogenation of furfural to produce furfuryl alcohol(FFA).It exhibited excellent catalytic performance,with high conversion(98.8%)and selectivity(98.5%)by using 2-propanol as hydrogen source under a relatively mild condition.Moreover,the Hf-PDCA has strong stability and durability,and can be recovered after the catalyst reaction.In addition,the Hf-PDCA as catalyst can be extended to fabricate corresponding alcohols by catalytic conversion of other biomass derived aldehydes.
