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Tuning the product selectivity of dimethyl oxalate hydrogenation over WO_(x) modified Cu/SiO_(2) catalysts
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作者 Zheng Li Zhuo Ma +9 位作者 Yihui Li Ziang Zhao Yuan Tan Ziyin Liu Xingkun Chen Nian Lei Huigang Wang Wei Lu Hejun Zhu Yunjie Ding 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第10期128-138,I0004,共12页
Product selectivity and reaction pathway are highly dependent on surface structure of heterogeneous catalysts.For vapor-phase hydrogenation of dimethyl oxalate(DMO),"EG route"(DMO→methyl glycolate(MG)ethyle... Product selectivity and reaction pathway are highly dependent on surface structure of heterogeneous catalysts.For vapor-phase hydrogenation of dimethyl oxalate(DMO),"EG route"(DMO→methyl glycolate(MG)ethylene glycol(EG)→ethanol(ET))and"MA route"(DMO→MG→methyl acetate(MA))were proposed over traditional Cu based catalysts and Mo-based or Fe-based catalysts,respectively.Herein,tunable yield of ET(93.7%)and MA(72.1%)were obtained through different reaction routes over WO_(x) modified Cu/SiO_(2) catalysts,and the corresponding reaction route was further proved by kinetic study and in-situ DRIFTS technology.Mechanistic studies demonstrated that H_(2) activation ability,acid density and Cu-WO_(x) interaction on the catalysts were tuned by regulating the surface W density,which resulted in the different reaction pathway and product selectivity.What's more,high yield of MA produced from DMO hydrogenation was firstly reported with the H_(2) pressure as low as 0.5 MPa. 展开更多
关键词 ETHANOL Dimethyl oxalate Selective hydrogenation Methyl acetate WCu/sio_(2)catalyst
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Bimetallic In_(2)O_(3)/Bi_(2)O_(3) Catalysts Enable Highly Selective CO_(2) Electroreduction to Formate within Ultra-Broad Potential Windows 被引量:1
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作者 Zhongxue Yang Hongzhi Wang +7 位作者 Xinze Bi Xiaojie Tan Yuezhu Zhao Wenhang Wang Yecheng Zou Huai ping Wang Hui Ning Mingbo Wu 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2024年第1期257-264,共8页
CO_(2)electrochemical reduction reaction(CO_(2)RR)to formate is a hopeful pathway for reducing CO_(2)and producing high-value chemicals,which needs highly selective catalysts with ultra-broad potential windows to meet... CO_(2)electrochemical reduction reaction(CO_(2)RR)to formate is a hopeful pathway for reducing CO_(2)and producing high-value chemicals,which needs highly selective catalysts with ultra-broad potential windows to meet the industrial demands.Herein,the nanorod-like bimetallic ln_(2)O_(3)/Bi_(2)O_(3)catalysts were successfully synthesized by pyrolysis of bimetallic InBi-MOF precursors.The abundant oxygen vacancies generated from the lattice mismatch of Bi_(2)O_(3)and ln_(2)O_(3)reduced the activation energy of CO_(2)to*CO_(2)·^(-)and improved the selectivity of*CO_(2)·^(-)to formate simultaneously.Meanwhile,the carbon skeleton derived from the pyrolysis of organic framework of InBi-MOF provided a conductive network to accelerate the electrons transmission.The catalyst exhibited an ultra-broad applied potential window of 1200 mV(from-0.4 to-1.6 V vs RHE),relativistic high Faradaic efficiency of formate(99.92%)and satisfactory stability after 30 h.The in situ FT-IR experiment and DFT calculation verified that the abundant oxygen vacancies on the surface of catalysts can easily absorb CO_(2)molecules,and oxygen vacancy path is dominant pathway.This work provides a convenient method to construct high-performance bimetallic catalysts for the industrial application of CO_(2)RR. 展开更多
关键词 bimetallic catalyst CO_(2)electrochemical reduction reaction FORMATE oxygen vacancy wide potential window
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Two-dimensional C_(2)N-based single-atom catalyst with complex microenvironment for enhanced electrochemical nitrogen reduction:A descriptor-based design
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作者 Enduo Dai Wei An +4 位作者 Ruixian Guo Xugen Shi Yunyi Li Yibo Wang Mingming Liu 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第10期110-119,I0003,共11页
The catalytic descriptor with operational feasibility is highly desired towards rational design of high-performance catalyst especially the electrode/electrolyte solution interface working under mild conditions.Herein... The catalytic descriptor with operational feasibility is highly desired towards rational design of high-performance catalyst especially the electrode/electrolyte solution interface working under mild conditions.Herein,we demonstrate that the descriptorΩparameterized by readily accessible intrinsic properties of metal center and coordination is highly operational and efficient in rational design of single-atom catalyst(SAC)for driving electrochemical nitrogen reduction(NRR).Using twodimensional metal(M)-B_(x)P_(y)S_(z)N_m@C_(2)N as prototype SAC models,we reveal that^(*)N_(2)+(H~++e~-)→^(*)N_(2)H acts predominantly as the potential-limiting step(PLS)of NRR on M-B_(2)P_(2)S_(2)@C_(2)N and M-B_(1)P_(1)S_(1)N_(3)@C_(2)N regardless of the distinction in coordination microenvironment.Among the 28 screened M active sites,withΩvalues close to the optimal 4,M-B_(2)P_(2)S_(2)@C_(2)N(M=V(Ω=3.53),Mo(Ω=5.12),and W(Ω=3.92))and M-B_(1)P_(1)S_(1)N_(3)@C_(2)N(M=V(Ω=3.00),Mo(Ω=4.34),and W(Ω=3.32))yield the lowered limiting potential(U_(L))as-0.45,-0.54.-0.36,-0.58,-0.25,and-0.24 V,respectively,thus making them the promising NRR catalysts.More importantly,these SACs are located around the top of volcano-shape plot of U_(L) versusΩ,re-validatingΩas an effective descriptor for accurately predicting the high-activity NRR SACs even with complex coordination.Our study unravels the relationship between active-site structure and NRR performance via the descriptorΩ,which can be applied to other important sustainable electrocatalytic reactions involving activation of small molecules viaσ-donation andπ^(*)-backdonation mechanism. 展开更多
关键词 ELECTROCATALYSIS N_(2) reduction Single-atom catalyst DESCRIPTOR DFT
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Elucidating the structure-activity relationship of Cu-Ag bimetallic catalysts for electrochemical CO_(2) reduction
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作者 Qining Huang Lili Wan +1 位作者 Qingxuan Ren Jingshan Luo 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第6期345-351,I0009,共8页
Developing bimetallic catalysts is an effective strategy for enhancing the activity and selectivity of electrochemical CO_(2) reduction reactions,where understanding the structure-activity relationship is essential fo... Developing bimetallic catalysts is an effective strategy for enhancing the activity and selectivity of electrochemical CO_(2) reduction reactions,where understanding the structure-activity relationship is essential for catalyst design.Herein,we prepared two Cu-Ag bimetallic catalysts with Ag nanoparticles attached to the top or the bottom of Cu nanowires.When tested in a flow cell,the Cu-Ag catalyst with Ag nanoparticles on the bottom achieved a faradaic efficiency of 54%for ethylene production,much higher than the catalyst with Ag nanoparticles on the top.The catalysts were further studied in the H-cell and zero-gap MEA cell.It was found that placing the two metals in the intensified reaction zone is crucial to triggering the tandem reaction of bimetallic catalysts.Our work elucidates the structure-activity relationship of bimetallic catalysts for CO_(2) reduction and demonstrates the importance of considering both catalyst structures and cell characteristics to achieve high activity and selectivity. 展开更多
关键词 Electrochemical CO_(2)reduction Bimetallic catalyst CU-AG Structure-activity relationship
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Sabatier principle guiding the design of cathode catalysts for Li-CO_(2) batteries
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作者 Haonan Xie Yimin Zhang +4 位作者 Biao Chen Chunnian He Chunsheng Shi Enzuo Liu Naiqin Zhao 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第10期585-592,I0012,共9页
The Sabatier principle has been widely used for designing electrocatalysts for energy conversion applications,but it is rarely mentioned in the research of cathode catalyst of Li-CO_(2) batteries.In our work,the"... The Sabatier principle has been widely used for designing electrocatalysts for energy conversion applications,but it is rarely mentioned in the research of cathode catalyst of Li-CO_(2) batteries.In our work,the"volcanic"relationship between the catalytic activity and the adsorption energy of the catalyst to the intermediates is first demonstrated based on the first-principles calculation,which meets the Sabatier principle and can be used to design the cathode catalysts.The increases in the number of nitrogenvacancy in WN shift the d-band center and increase the interaction with the reactants.The catalytic activity increases first and then decreases with the increase of adsorption energy,which was proved in the experiment.The optimal catalyst for moderate adsorption of intermediate makes the thin LiaCO_(3) distribute evenly.It exhibits a median voltage difference of 0.68 V and an energy efficiency of 84.33%at20μA cm^(-2)with a limited capacity of 200μA h cm^(-2). 展开更多
关键词 Sabatier principle Bidirectional catalyst Transition metal nitrides Nitrogen-vacancy Li-CO_(2) batteries
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Molecular engineering binuclear copper catalysts for selective CO_(2) reduction to C_(2) products
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作者 Qi Zhao Kai Lei +2 位作者 Bao Yu Xia Rachel Crespo-Otero Devis Di Tommaso 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第6期166-173,I0005,共9页
Molecular copper catalysts serve as exemplary models for correlating the structure-reaction-mechanism relationship in the electrochemical CO_(2) reduction(eCO_(2)R),owing to their adaptable environments surrounding th... Molecular copper catalysts serve as exemplary models for correlating the structure-reaction-mechanism relationship in the electrochemical CO_(2) reduction(eCO_(2)R),owing to their adaptable environments surrounding the copper metal centres.This investigation,employing density functional theory calculations,focuses on a novel family of binuclear Cu molecular catalysts.The modulation of their coordination configuration through the introduction of organic groups aims to assess their efficacy in converting CO_(2) to C_(2)products.Our findings highlight the crucial role of chemical valence state in shaping the characteristics of binuclear Cu catalysts,consequently influencing the eCO_(2)R behaviour,Notably,the Cu(Ⅱ)Cu(Ⅱ)macrocycle catalyst exhibits enhanced suppression of the hydrogen evolution reaction(HER),facilitating proton trans fer and the eCO_(2)R process.Fu rthermore,we explo re the impact of diverse electro n-withdrawing and electron-donating groups coordinated to the macrocycle(R=-F,-H,and-OCH_3)on the electron distribution in the molecular catalysts.Strategic placement of-OCH_3 groups in the macrocycles leads to a favourable oxidation state of the Cu centres and subsequent C-C coupling to form C_(2) products.This research provides fundamental insights into the design and optimization of binuclear Cu molecular catalysts for the electrochemical conversion of CO_(2) to value-added C_(2) products. 展开更多
关键词 Molecular catalyst design Selective CO_(2)reduction C_(2)products Density functional theory calculations
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CO_(2)-assisted oxidation dehydrogenation of light alkanes over metal-based heterogeneous catalysts
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作者 Yingbin Zheng Xinbao Zhang +4 位作者 Junjie Li Jie An Longya Xu Xiujie Li Xiangxue Zhu 《Chinese Journal of Catalysis》 SCIE CAS CSCD 2024年第10期40-69,共30页
Light olefins are important platform feedstocks in the petrochemical industry,and the ongoing global economic development has driven sustained growth in demand for these compounds.The dehydrogenation of alkanes,derive... Light olefins are important platform feedstocks in the petrochemical industry,and the ongoing global economic development has driven sustained growth in demand for these compounds.The dehydrogenation of alkanes,derived from shale gas,serves as an alternative olefins production route.Concurrently,the target of realizing carbon neutrality promotes the comprehensive utilization of greenhouse gas.The integrated process of light alkanes dehydrogenation and carbon dioxide reduction(CO_(2)-ODH)can produce light olefins and realize resource utilization of CO_(2),which has gained wide popularity.With the introduction of CO_(2),coke deposition and metal reduction encountered in alkanes dehydrogenation reactions can be effectively suppressed.CO_(2)-assisted alkanes dehydrogenation can also reduce the risk of potential explosion hazard associated with O_(2)-oxidative dehydrogenation reactions.Recent investigations into various metal-based catalysts including mono-and bi-metallic alloys and oxides have displayed promising performances due to their unique properties.This paper provides the comprehensive review and critical analysis of advancements in the CO_(2)-assisted oxidative dehydrogenation of light alkanes(C2-C4)on metal-based catalysts developed in recent years.Moreover,it offers a comparative summary of the structural properties,catalytic activities,and reaction mechanisms over various active sites,providing valuable insights for the future design of dehydrogenation catalysts. 展开更多
关键词 Light alkanes dehydrogenation CO_(2)utilization Metal-based catalysts Light olefins Coupling reaction
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Chalcogen heteroatoms doped nickel-nitrogen-carbon single-atom catalysts with asymmetric coordination for efficient electrochemical CO_(2) reduction
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作者 Jialin Wang Kaini Zhang +5 位作者 Ta Thi Thuy Ng Yiqing Wang Yuchuan Shi Daixing Wei Chung-Li Dong Shaohua Shen 《Chinese Journal of Catalysis》 SCIE CAS CSCD 2024年第9期54-65,共12页
The electronic configuration of central metal atoms in single-atom catalysts(SACs)is pivotal in electrochemical CO_(2) reduction reaction(eCO_(2)RR).Herein,chalcogen heteroatoms(e.g.,S,Se,and Te)were incorporated into... The electronic configuration of central metal atoms in single-atom catalysts(SACs)is pivotal in electrochemical CO_(2) reduction reaction(eCO_(2)RR).Herein,chalcogen heteroatoms(e.g.,S,Se,and Te)were incorporated into the symmetric nickel-nitrogen-carbon(Ni-N_(4)-C)configuration to obtain Ni-X-N_(3)-C(X:S,Se,and Te)SACs with asymmetric coordination presented for central Ni atoms.Among these obtained Ni-X-N_(3)-C(X:S,Se,and Te)SACs,Ni-Se-N_(3)-C exhibited superior eCO_(2)RR activity,with CO selectivity reaching~98% at-0.70 V versus reversible hydrogen electrode(RHE).The Zn-CO_(2) battery integrated with Ni-Se-N_(3)-C as cathode and Zn foil as anode achieved a peak power density of 1.82 mW cm^(-2) and maintained remarkable rechargeable stability over 20 h.In-situ spectral investigations and theoretical calculations demonstrated that the chalcogen heteroatoms doped into the Ni-N_(4)-C configuration would break coordination symmetry and trigger charge redistribution,and then regulate the intermediate behaviors and thermodynamic reaction pathways for eCO_(2)RR.Especially,for Ni-Se-N_(3)-C,the introduced Se atoms could significantly raise the d-band center of central Ni atoms and thus remarkably lower the energy barrier for the rate-determining step of ^(*)COOH formation,contributing to the promising eCO_(2)RR performance for high selectivity CO production by competing with hydrogen evolution reaction. 展开更多
关键词 Electrochemical CO_(2) reduction reaction Chalcogen heteroatoms Single-atom catalysts Asymmetric coordination CO production
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A cascade of in situ conversion of bicarbonate to CO_(2) and CO_(2) electroreduction in a flow cell with a Ni-N-S catalyst
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作者 Linghui Kong Min Wang +6 位作者 Yongxiao Tuo Shanshan Zhou Jinxiu Wang Guangbo Liu Xuejing Cui Jiali Wang Luhua Jiang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第1期183-193,I0005,共12页
Combination of CO_(2) capture using inorganic alkali with subsequently electrochemical conversion of the resultant HCO_(3)^(-)to high-value chemicals is a promising route of low cost and high efficiency.The electroche... Combination of CO_(2) capture using inorganic alkali with subsequently electrochemical conversion of the resultant HCO_(3)^(-)to high-value chemicals is a promising route of low cost and high efficiency.The electrochemical reduction of HCO_(3)^(-)is challenging due to the inaccessible of negatively charged molecular groups to the electrode surface.Herein,we adopt a comprehensive strategy to tackle this challenge,i.e.,cascade of in situ chemical conversion of HCO_(3)^(-)to CO_(2) and CO_(2) electrochemical reduction in a flow cell.With a tailored Ni-N-S single atom catalyst(SACs),where sulfur(S)atoms located in the second shell of Ni center,the CO_(2)electroreduction(CO_(2)ER)to CO is boosted.The experimental results and density functional theory(DFT)calculations reveal that the introduction of S increases the p electron density of N atoms near Ni atom,thereby stabilizing^(*)H over N and boosting the first proton coupled electron transfer process of CO_(2)ER,i.e.,^(*)+e^(-)+^(*)H+^(*)CO_(2)→^(*)COOH.As a result,the obtained catalyst exhibits a high faradaic efficiency(FE_(CO)~98%)and a low overpotential of 425 mV for CO production as well as a superior turnover frequency(TOF)of 47397 h^(-1),outcompeting most of the reported Ni SACs.More importantly,an extremely high FECOof 90%is achieved at 50 mA cm^(-2)in the designed membrane electrode assembly(MEA)cascade electrolyzer fed with liquid bicarbonate.This work not only highlights the significant role of the second coordination on the first coordination shell of the central metal for CO_(2)ER,but also provides an alternative and feasible strategy to realize the electrochemical conversion of HCO_(3)^(-)to high-value chemicals. 展开更多
关键词 S doped Ni-N-C single atom catalysts CO_(2)electrochemical reduction DFT calculations Membrane electrode assembly Reduction of bicarbonate
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Ca and Sr co-doping induced oxygen vacancies in 3DOM La_(2-x)Sr_(x)Ce_(2-y)CayO_(7-δ)catalysts for boosting low-temperature oxidative coupling of methane
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作者 Tongtong Wu Yuechang Wei +5 位作者 Jing Xiong Yitao Yang Zhenpeng Wang Dawei Han Zhen Zhao Jian Liu 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第4期331-344,共14页
It is urgent to develop catalysts with application potential for oxidative coupling of methane(OCM)at relatively lower temperature.Herein,three-dimensional ordered macro porous(3 DOM)La_(2-x)Sr_(x)Ce_(2-y)CayO_(7-δ)(... It is urgent to develop catalysts with application potential for oxidative coupling of methane(OCM)at relatively lower temperature.Herein,three-dimensional ordered macro porous(3 DOM)La_(2-x)Sr_(x)Ce_(2-y)CayO_(7-δ)(A_(2)B_(2)O_(7)-type)catalysts with disordered defective cubic fluorite phased structure were successfully prepared by a colloidal crystal template method.3DOM structure promotes the accessibility of the gaseous reactants(O2and CH4)to the active sites.The co-doping of Ca and Sr ions in La_(2-x)Sr_(x)Ce_(2-y)CayO_(7-δ)catalysts improved the formation of oxygen vacancies,thereby leading to increased density of surface-active oxygen species(O_(2)^(-))for the activation of CH4and the formation of C2products(C2H6and C2H4).3DOM La_(2-x)Sr_(x)Ce_(2-y)CayO_(7-δ)catalysts exhibit high catalytic activity for OCM at low temperature.3DOM La1.7Sr0.3Ce1.7Ca0.3O7-δcatalyst with the highest density of O_(2)^(-)species exhibited the highest catalytic activity for low-temperature OCM,i.e.,its CH4conversion,selectivity and yield of C2products at 650℃are 32.2%,66.1%and 21.3%,respectively.The mechanism was proposed that the increase in surface oxygen vacancies induced by the co-doping of Ca and Sr ions boosts the key step of C-H bond breaking and C-C bond coupling in catalyzing low-temperature OCM.It is meaningful for the development of the low-temperature and high-efficient catalysts for OCM reaction in practical application. 展开更多
关键词 3DOM catalysts Ca ions Sr ions Low-temperature oxidative couplingof methane Oxygen vacancies O_(2)^(-) species
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Accelerating the Screening of Modified MA_(2)Z_(4) Catalysts for Hydrogen Evolution Reaction by Deep Learning-Based Local Geometric Analysis
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作者 Jingnan Zheng Shibin Wang +3 位作者 Shengwei Deng Zihao Yao Junhua Hu Jianguo Wang 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2024年第6期290-302,共13页
Machine learning(ML)integrated with density functional theory(DFT)calculations have recently been used to accelerate the design and discovery of single-atom catalysts(SACs)by establishing deep structure–activity rela... Machine learning(ML)integrated with density functional theory(DFT)calculations have recently been used to accelerate the design and discovery of single-atom catalysts(SACs)by establishing deep structure–activity relationships.The traditional ML models are always difficult to identify the structural differences among the single-atom systems with different modification methods,leading to the limitation of the potential application range.Aiming to the structural properties of several typical two-dimensional MA_(2)Z_(4)-based single-atom systems(bare MA_(2)Z_(4) and metal single-atom doped/supported MA_(2)Z_(4)),an improved crystal graph convolutional neural network(CGCNN)classification model was employed,instead of the traditional machine learning regression model,to address the challenge of incompatibility in the studied systems.The CGCNN model was optimized using crystal graph representation in which the geometric configuration was divided into active layer,surface layer,and bulk layer(ASB-GCNN).Through ML and DFT calculations,five potential single-atom hydrogen evolution reaction(HER)catalysts were screened from chemical space of 600 MA_(2)Z_(4)-based materials,especially V_(1)/HfSn_(2)N_(4)(S)with high stability and activity(Δ_(GH*)is 0.06 eV).Further projected density of states(pDOS)analysis in combination with the wave function analysis of the SAC-H bond revealed that the SAC-dz^(2)orbital coincided with the H-s orbital around the energy level of−2.50 eV,and orbital analysis confirmed the formation ofσbonds.This study provides an efficient multistep screening design framework of metal single-atom catalyst for HER systems with similar two-dimensional supports but different geometric configurations. 展开更多
关键词 graph convolutional neural network hydrogen evolution reaction modified MA_(2)Z_(4) substrate single atom catalyst
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Single-atom catalysts based on polarization switching of ferroelectric In_(2)Se_(3) for N_(2) reduction
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作者 Nan Mu Tingting Bo +3 位作者 Yugao Hu Ruixin Xu Yanyu Liu Wei Zhou 《Chinese Journal of Catalysis》 SCIE CAS CSCD 2024年第8期244-257,共14页
The polarization switching plays a crucial role in controlling the final products in the catalytic pro-cess.The effect of polarization orientation on nitrogen reduction was investigated by anchoring transition metal a... The polarization switching plays a crucial role in controlling the final products in the catalytic pro-cess.The effect of polarization orientation on nitrogen reduction was investigated by anchoring transition metal atoms to form active centers on ferroelectric material In_(2)Se_(3).During the polariza-tion switching process,the difference in surface electrostatic potential leads to a redistribution of electronic states.This affects the interaction strength between the adsorbed small molecules and the catalyst substrate,thereby altering the reaction barrier.In addition,the surface states must be considered to prevent the adsorption of other small molecules(such as *O,*OH,and *H).Further-more,the V@↓-In_(2)Se_(3) possesses excellent catalytic properties,high electrochemical and thermody-namic stability,which facilitates the catalytic process.Machine learning also helps us further ex-plore the underlying mechanisms.The systematic investigation provides novel insights into the design and application of two-dimensional switchable ferroelectric catalysts for various chemical processes. 展开更多
关键词 In_(2)Se_(3) monolayer Density functional theory Ferroelectric switching Single atom catalysts Nitrogen reduction reaction Machine learning
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The role of copper in enhancing the performance of heteronuclear diatomic catalysts for the electrochemical CO_(2)conversion to C_(1) chemicals 被引量:2
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作者 Qi Zhao Rachel Crespo-Otero Devis Di Tommaso 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第10期490-500,I0013,共12页
Diatomic catalysts(DACs)with two adjacent metal atoms supported on graphene can offer diverse functionalities,overcoming the inherent limitations of single atom catalysts(SACs).In this study,density functional theory ... Diatomic catalysts(DACs)with two adjacent metal atoms supported on graphene can offer diverse functionalities,overcoming the inherent limitations of single atom catalysts(SACs).In this study,density functional theory calculations were conducted to investigate the reactivity of the carbon dioxide(CO_(2))reduction reaction(CO_(2)RR)on metal sites of both DACs and SACs,as well as their synergistic effects on activity and selectivity.Calculation of the Gibbs free energies of CO_(2)RR and associated values of the limiting potentials to generate C_(1) products showed that Cu acts as a promoter rather than an active catalytic centre in the catalytic CO_(2)conversion on heteronuclear DACs(CuN_(4)-MN_(4)),improving the catalytic activity on the other metal compared to the related SAC MN_(4).Cu enhances the initial reduction of CO_(2)by promoting orbital hybridization between the key intermediate*COOH 2p-orbitals and the metals 3d-orbitals around the Fermi level.This degree of hybridization in the DACs CuN_(4)-MN_(4) decreases from Fe to Co,Ni,and Zn.Our work demonstrates how Cu regulates the CO_(2)RR performance of heteronuclear DACs,offering an effective approach to designing practical,stable,and high-performing diatomic catalysts for CO_(2)electroreduction. 展开更多
关键词 Electrocatalytic CO_(2)reduction Single atom catalysts Diatomic catalysts Graphene Density functional theory calculations
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Application of Acid Modified Catalysts with Different SiO_(2) Contents in the Hydrocracking of Light Cycle Oil for Light Aromatics Production
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作者 Zhong Fu Zuo Tongjiu +1 位作者 Xie Yonggang Lu Jiangyin 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS CSCD 2023年第1期105-114,共10页
A series of functionalized USY/SiO_(2) zeolite composite supports were synthesized using the coating coprecipitation method,with tetraethyl orthosilicate(TEOS)as the silicon source and different ratios of USY to TEOS.... A series of functionalized USY/SiO_(2) zeolite composite supports were synthesized using the coating coprecipitation method,with tetraethyl orthosilicate(TEOS)as the silicon source and different ratios of USY to TEOS.Active metals nickel(Ni)and molybdenum(Mo)were loaded onto the supports using the impregnation method.Finally,a series of hydrogenation catalysts were synthesized.The characterization results showed that,compared with the USY catalyst,the addition of a certain quantity of SiO_(2) resulted in the disappearance of the strong acid sites on the catalyst,the number of weak acid and medium strong acid sites decreased,and a certain number of secondary mesoporous structures were formed.The addition of SiO_(2) reduced the secondary cracking of benzene,toluene,xylene,and ethylbenzene(BTXE)effectively,while excessive amounts of SiO_(2) reduced the hydrogenation activity of the catalyst,leading to a decline in the final yield of BTXE.At a maximum SiO_(2) content of 45%,the hydrogenation depth of light cycle oil(LCO)reached an optimum value.The hydrogenation performance of LCO was investigated in a fixed bed reactor at 380℃,4 MPa,and H2/oil volume ratio of 800:1,where the gasoline and diesel fractions reached 80.00%and 16.74%,respectively.NiMo-YS45 had the highest BTXE selectivity,and the final yield of BTXE reached 21.27%. 展开更多
关键词 zeolite catalyst HYDROCRACKING sio_(2) LCO BTXE
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CO_(2)utilization in syngas conversion to dimethyl ether and aromatics:Roles and challenges of zeolites-based catalysts
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作者 Ali A.Al-Qadri Galal A.Nasser +2 位作者 Haruna Adamu Oki Muraza Tawfik A.Saleh 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第4期418-449,共32页
Several studies have proven a strong correlation between global warming and CO_(2)emissions.Annually,38 billion tons of CO_(2)are approximately emitted into the atmosphere.Utilizing CO_(2)via chemical conversion to cl... Several studies have proven a strong correlation between global warming and CO_(2)emissions.Annually,38 billion tons of CO_(2)are approximately emitted into the atmosphere.Utilizing CO_(2)via chemical conversion to clean fuels and value-added aromatics can substantially contribute to controlling the problem.Considering the thermodynamic and environmental limitations of hydrogenation of CO_(2)alone to value-added aromatics and fuels,CO_(2)utilization has currently emerged as a promising and practical approach for the production of fuels and aromatics with simultaneous utilization of both CO and CO_(2)wastes.As such,the approach is economically preferable.CO_(2)could be converted directly to fuels by the hydrogenation process or as a part of a syngas mixture.Dimethyl ether(DME)is a clean fuel with a higher energy density,which could be used as a substituent for several fuels such as diesel.In the same vein,value-added aromatics such as benzene,toluene,and xylene(BTX)can be produced from a similar process.Herein,we report a review that collects the most recent studies for the conversion of CO_(2)to DME and aromatics via zeolite-based bifunctional catalysts.We highlighted the main routes for producing DME and aromatics,as well as thoroughly discussed the conducted studies on CO_(2)hydrogenation and CO_(2)-rich syngas utilized as feedstock for conversion to DME and aromatics.The CO_(2)hydrogenation mostly occurs through the methanol-mediated reaction route but is most often limited by low selectivity and catalyst deactivation,particularly in the utilization of CO_(2)alone for the reduction reaction.The review takes an overview of the progress made so far and concluded by identifying the roles and challenges of zeolite-based catalysts for CO_(2)utilization and conversion to DME and aromatics.Accordingly,despite the incredible growth the field received in the last couple of years,however,many research challenges and opportunities associated with this process are still abounded and required to be addressed.Special attention is required for the development of approaches to block diffusion of H2O through zeolite to suppress the excess formation of CO_(2)in CO_(2)-rich syngas hydrogenation to DME and aromatics,exceed the product distribution limits,and suppress catalysts deactivation. 展开更多
关键词 Clean fuel DME AROMATICS Bifunctional catalyst CO_(2)mitigation
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季冻区纳米SiO_(2)改性SAP路面混凝土的耐磨性
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作者 申爱琴 陈荣伟 +3 位作者 郭寅川 范建航 戴晓倩 丑涛 《材料导报》 EI CAS CSCD 北大核心 2024年第7期56-61,共6页
为解决季冻区高吸水性树脂(SAP)路面混凝土耐磨性下降的问题,通过耐磨性试验探索了纳米SiO_(2)(NS)对季冻区SAP路面混凝土磨损量的影响;采用压汞仪(MIP)和扫描电镜(SEM)研究了冻融前后NS改性SAP路面混凝土孔结构和微观形貌的变化,从细... 为解决季冻区高吸水性树脂(SAP)路面混凝土耐磨性下降的问题,通过耐磨性试验探索了纳米SiO_(2)(NS)对季冻区SAP路面混凝土磨损量的影响;采用压汞仪(MIP)和扫描电镜(SEM)研究了冻融前后NS改性SAP路面混凝土孔结构和微观形貌的变化,从细微观角度阐述其耐磨性的提升机理;并对其微观结构与耐磨性进行相关性分析。研究结果表明,经150次冻融循环之后,掺有3%NS的改性SAP路面混凝土在200 N磨耗负荷下的磨损量较基准下降30.92%,20~50nm的孔占比上升,50~200nm的孔占比下降,总孔隙量和孔隙率减少,界面区裂缝数量和尺寸大幅降低,内部密实性程度显著提高,耐磨性明显增强。 展开更多
关键词 季冻区 路面混凝土纳米二氧化硅 高吸水性树脂 耐磨性
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助剂对球形Cu/SiO_(2)催化剂甲醇脱氢制甲酸甲酯反应性能的影响 被引量:1
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作者 靳钰婷 郭宇伟 +2 位作者 权燕红 赵金仙 任军 《低碳化学与化工》 CAS 北大核心 2024年第2期17-25,共9页
甲醇脱氢制甲酸甲酯是实现甲醇下游产品多元化利用的绿色高效途径,使用助剂对SiO_(2)催化剂进行改性已成为提高目标产物甲酸甲酯收率的有效策略。首先通过溶胶-凝胶法制备了球形SiO_(2)负载Cu催化剂(Cu/SiO_(2)),然后采用旋蒸法引入助... 甲醇脱氢制甲酸甲酯是实现甲醇下游产品多元化利用的绿色高效途径,使用助剂对SiO_(2)催化剂进行改性已成为提高目标产物甲酸甲酯收率的有效策略。首先通过溶胶-凝胶法制备了球形SiO_(2)负载Cu催化剂(Cu/SiO_(2)),然后采用旋蒸法引入助剂制得CuM/SiO_(2)(M=Ce或Al)催化剂,借助N2吸/脱附、扫描电子显微镜(SEM)、H_(2)-N_(2)O滴定和X射线衍射(XRD)等手段对催化剂进行了表征,并将催化剂用于甲醇脱氢制甲酸甲酯反应评价了其催化性能。结果表明,助剂可改变催化剂中活性Cu^(0)物种的含量和表面酸碱性。与Cu/SiO_(2)催化剂相比,CuCe/SiO_(2)催化剂表面Cu颗粒的分散度提高,这促进了活性物种Cu^(0)的形成,同时表面碱性位点减少,抑制了副反应发生,因而CuCe/SiO_(2)催化剂表现出最高的活性。在300℃、0.2 MPa的反应条件下,CuCe/SiO_(2)催化剂的甲醇转化率、甲酸甲酯选择性分别为29.2%、86.3%,甲酸甲酯收率为25.2%,均明显优于文献报道的Cu基催化剂。 展开更多
关键词 甲醇脱氢 Cu基催化剂 球形sio2 甲酸甲酯 助剂
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介孔WO_(3)/SiO_(2)的制备及其氧化脱硫性能 被引量:1
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作者 张敬唯 赵茹玉 +4 位作者 何苗 王阳 张银海 刘晓雪 李颢 《云南化工》 CAS 2024年第5期55-59,共5页
以稻壳为硅源和介孔模板,磷钨酸为钨源,采用等体积浸渍法制备了一系列不同WO_(3)负载量的介孔WO_(3)/SiO_(2)催化剂。结果表明,低负载量的样品,WO_(3)晶粒在载体SiO_(2)上高度分散,且样品的比表面积、外表面积和介孔体积均较高。采用二... 以稻壳为硅源和介孔模板,磷钨酸为钨源,采用等体积浸渍法制备了一系列不同WO_(3)负载量的介孔WO_(3)/SiO_(2)催化剂。结果表明,低负载量的样品,WO_(3)晶粒在载体SiO_(2)上高度分散,且样品的比表面积、外表面积和介孔体积均较高。采用二苯并噻吩(DBT)和4,6-二甲基二苯并噻吩(4,6-DMDBT)模拟油的氧化脱硫反应,评价了样品的催化性能。在优化的条件下,2.4%WO_(3)/SiO_(2)样品给出了99.9%的DBT转化率和99.5%的4,6-DMDBT转化率。 展开更多
关键词 稻壳 介孔 WO_(3)/sio_(2)催化剂 氧化脱硫
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Enabling heterogeneous catalysis to achieve carbon neutrality: Directional catalytic conversion of CO_(2) into carboxylic acids 被引量:7
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作者 Xiaofei Zhang Wenhuan Huang +4 位作者 Le Yu Max García-Melchor Dingsheng Wang Linjie Zhi Huabin Zhang 《Carbon Energy》 SCIE EI CAS CSCD 2024年第3期1-35,共35页
The increase in anthropogenic carbon dioxide(CO_(2))emissions has exacerbated the deterioration of the global environment,which should be controlled to achieve carbon neutrality.Central to the core goal of achieving c... The increase in anthropogenic carbon dioxide(CO_(2))emissions has exacerbated the deterioration of the global environment,which should be controlled to achieve carbon neutrality.Central to the core goal of achieving carbon neutrality is the utilization of CO_(2) under economic and sustainable conditions.Recently,the strong need for carbon neutrality has led to a proliferation of studies on the direct conversion of CO_(2) into carboxylic acids,which can effectively alleviate CO_(2) emissions and create high-value chemicals.The purpose of this review is to present the application prospects of carboxylic acids and the basic principles of CO_(2) conversion into carboxylic acids through photo-,electric-,and thermal catalysis.Special attention is focused on the regulation strategy of the activity of abundant catalysts at the molecular level,inspiring the preparation of high-performance catalysts.In addition,theoretical calculations,advanced technologies,and numerous typical examples are introduced to elaborate on the corresponding process and influencing factors of catalytic activity.Finally,challenges and prospects are provided for the future development of this field.It is hoped that this review will contribute to a deeper understanding of the conversion of CO_(2) into carboxylic acids and inspire more innovative breakthroughs. 展开更多
关键词 carbon neutrality carboxylic acids CO_(2)conversion heterogeneous catalyst in situ technology
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纳米SiO_(2)界面剂对新旧混凝土界面抗渗性能和微观结构影响研究
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作者 周韬剑 杨才千 +2 位作者 李科锋 曾领雄 许福 《湘潭大学学报(自然科学版)》 CAS 2024年第1期14-23,69,共11页
采用试验的方法探究了纳米SiO_(2)界面剂对新旧混凝土界面劈裂黏结强度和抗渗性能的影响,其使用形式包括喷洒稀释溶液及作为增强相的砂浆界面剂两种方式,并与整体现浇试件及传统界面凿毛组的抗渗性能进行对比分析.同时,借助扫描电子显微... 采用试验的方法探究了纳米SiO_(2)界面剂对新旧混凝土界面劈裂黏结强度和抗渗性能的影响,其使用形式包括喷洒稀释溶液及作为增强相的砂浆界面剂两种方式,并与整体现浇试件及传统界面凿毛组的抗渗性能进行对比分析.同时,借助扫描电子显微镜(SEM)对不同纳米界面剂的黏结面微观结构进行了探究.最后,从界面强度、抗渗性能和微观机理3方面分析了纳米SiO_(2)界面剂对新旧混凝土界面黏结性能的影响.结果表明:两种纳米SiO_(2)界面剂均能不同程度地提高界面黏结强度及其抗渗性能,其中纳米SiO_(2)砂浆界面剂效果明显优于纳米SiO_(2)溶液组,且两者均存在最优掺量,分别为3.75%和2.5%;随着界面粗糙度的增加,黏结试件渗水高度和相对渗透系数逐渐降低;界面相对渗透系数与劈裂强度呈负相关,且相比于劈裂强度,相对渗透系数对界面缺陷更敏感.微观分析结果表明:纳米SiO_(2)的掺入改变了界面过渡区(ITZ)水化产物数量和C-S-H凝胶形貌,有效抑制了界面孔隙网络贯通,使ITZ微观结构更为致密. 展开更多
关键词 界面剂 界面处理 纳米sio2 黏结性能 渗透试验
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