Against the backdrop of escalating global climate change and energy crises,the resource utilization of carbon dioxide(CO_(2)),a major greenhouse gas,has become a crucial pathway for achieving carbon peaking and carbon...Against the backdrop of escalating global climate change and energy crises,the resource utilization of carbon dioxide(CO_(2)),a major greenhouse gas,has become a crucial pathway for achieving carbon peaking and carbon neutrality goals.The hydrogenation of CO_(2)to methanol not only enables carbon sequestration and recycling,but also provides a route to produce high value-added fuels and basic chemical feedstocks,holding significant environmental and economic potential.However,this conversion process is thermodynamically and kinetically limited,and traditional catalyst systems(e.g.,Cu/ZnO/Al_(2)O_(3))exhibit inadequate activity,selectivity,and stability under mild conditions.Therefore,the development of novel high-performance catalysts with precisely tunable structures and functionalities is imperative.Metal-organic frameworks(MOFs),as crystalline porous materials with high surface area,tunable pore structures,and diverse metal-ligand compositions,have the great potential in CO_(2)hydrogenation catalysis.Their structural design flexibility allows for the construction of well-dispersed active sites,tailored electronic environments,and enhanced metal-support interactions.This review systematically summarizes the recent advances in MOF-based and MOF-derived catalysts for CO_(2)hydrogenation to methanol,focusing on four design strategies:(1)spatial confinement and in situ construction,(2)defect engineering and ion-exchange,(3)bimetallic synergy and hybrid structure design,and(4)MOF-derived nanomaterial synthesis.These approaches significantly improve CO_(2)conversion and methanol selectivity by optimizing metal dispersion,interfacial structures,and reaction pathways.The reaction mechanism is further explored by focusing on the three main reaction pathways:the formate pathway(HCOO*),the RWGS(Reverse Water Gas Shift reaction)+CO*hydrogenation pathway,and the trans-COOH pathway.In situ spectroscopic studies and density functional theory(DFT)calculations elucidate the formation and transformation of key intermediates,as well as the roles of active sites,metal-support interfaces,oxygen vacancies,and promoters.Additionally,representative catalytic performance data for MOFbased systems are compiled and compared,demonstrating their advantages over traditional catalysts in terms of CO_(2)conversion,methanol selectivity,and space-time yield.Future perspectives for MOF-based CO_(2)hydrogenation catalysts will prioritize two main directions:structural design and mechanistic understanding.The precise construction of active sites through multi-metallic synergy,defect engineering,and interfacial electronic modulation should be made to enhance catalyst selectivity and stability.In addition,advanced in situ characterization techniques combined with theoretical modeling are essential to unravel the detailed reaction mechanisms and intermediate behaviors,thereby guiding rational catalyst design.Moreover,to enable industrial application,challenges related to thermal/hydrothermal stability,catalyst recyclability,and cost-effective large-scale synthesis must be addressed.The development of green,scalable preparation methods and the integration of MOF catalysts into practical reaction systems(e.g.,flow reactors)will be crucial for bridging the gap between laboratory research and commercial deployment.Ultimately,multi-scale structure-performance optimization and catalytic system integration will be vital for accelerating the industrialization of MOF-based CO_(2)-to-methanol technologies.展开更多
Using photoelectrocatalytic CO_(2) reduction reaction(CO_(2)RR)to produce valuable fuels is a fascinating way to alleviate environmental issues and energy crises.Bismuth-based(Bi-based)catalysts have attracted widespr...Using photoelectrocatalytic CO_(2) reduction reaction(CO_(2)RR)to produce valuable fuels is a fascinating way to alleviate environmental issues and energy crises.Bismuth-based(Bi-based)catalysts have attracted widespread attention for CO_(2)RR due to their high catalytic activity,selectivity,excellent stability,and low cost.However,they still need to be further improved to meet the needs of industrial applications.This review article comprehensively summarizes the recent advances in regulation strategies of Bi-based catalysts and can be divided into six categories:(1)defect engineering,(2)atomic doping engineering,(3)organic framework engineering,(4)inorganic heterojunction engineering,(5)crystal face engineering,and(6)alloying and polarization engineering.Meanwhile,the corresponding catalytic mechanisms of each regulation strategy will also be discussed in detail,aiming to enable researchers to understand the structure-property relationship of the improved Bibased catalysts fundamentally.Finally,the challenges and future opportunities of the Bi-based catalysts in the photoelectrocatalytic CO_(2)RR application field will also be featured from the perspectives of the(1)combination or synergy of multiple regulatory strategies,(2)revealing formation mechanism and realizing controllable synthesis,and(3)in situ multiscale investigation of activation pathways and uncovering the catalytic mechanisms.On the one hand,through the comparative analysis and mechanism explanation of the six major regulatory strategies,a multidimensional knowledge framework of the structure-activity relationship of Bi-based catalysts can be constructed for researchers,which not only deepens the atomic-level understanding of catalytic active sites,charge transport paths,and the adsorption behavior of intermediate products,but also provides theoretical guiding principles for the controllable design of new catalysts;on the other hand,the promising collaborative regulation strategies,controllable synthetic paths,and the in situ multiscale characterization techniques presented in this work provides a paradigm reference for shortening the research and development cycle of high-performance catalysts,conducive to facilitating the transition of photoelectrocatalytic CO_(2)RR technology from the laboratory routes to industrial application.展开更多
High performance CuO-CeO2 catalysts for selective oxidation of CO in excess hydrogen were prepared by a hydrothermal method under different preparation conditions and evaluated for catalytic activities and selectiviti...High performance CuO-CeO2 catalysts for selective oxidation of CO in excess hydrogen were prepared by a hydrothermal method under different preparation conditions and evaluated for catalytic activities and selectivities. By changing the ^nCTAB/^nCe ratio and hydrothermal aging time, the catalytic activity of the CuO-CeO2 catalysts increased and the operating temperature window, in which the CO conversion was higher than 99%, was widened. XRD results showed no peaks of CuOx species and Cu-Ce-O solid solution were observed. On the other hand, Cu＋ species in the CuO-CeO2 catalysts, which was associated with a strong interaction between copper oxide clusters and cerium oxide and could be favorable for improving the selective oxidation performance of CO in excess H2, were detected by H2-TPR and XPS techniques.展开更多
CuO-CeO2 catalysts were prepared by a urea precipitation method for the oxidative steam reforming of ethanol at low-temperature.The catalytic performance was evaluated and the catalysts were characterized by inductive...CuO-CeO2 catalysts were prepared by a urea precipitation method for the oxidative steam reforming of ethanol at low-temperature.The catalytic performance was evaluated and the catalysts were characterized by inductively coupled plasma atomic emission spectroscopy,X-ray diffraction,temperature-programmed reduction,field emission scanning electron microscopy and thermo-gravimetric analysis.Over CuOCeO2 catalysts,H2 with low CO content was produced in the whole tested temperature range of 250–450 C.The non-noble metal catalyst 20CuCe showed higher H2production rate than 1%Rh/CeO2 catalyst at 300–400 C and the advantage was more obvious after 20 h testing at400 C.These results further confirmed that CuO-CeO2 catalysts may be suitable candidates for low temperature hydrogen production from ethanol.展开更多
The effects of CeO2 contents and silica carrier porosity with their pore diameters ranging from 5.2 nm to 12.5 nm of CuO-CeO2/SiO2 cata-lysts in CO oxidation were investigated.The catalysts were characterized by N2 ad...The effects of CeO2 contents and silica carrier porosity with their pore diameters ranging from 5.2 nm to 12.5 nm of CuO-CeO2/SiO2 cata-lysts in CO oxidation were investigated.The catalysts were characterized by N2 adsorption/desorption at low temperature,X-ray diffraction （XRD）,temperature-programmed reduction by H2 （H2-TPR）,oxygen temperature programmed desorption （O2-TPD） and X-ray photoelectron spectroscopy （XPS）.The results suggested that,the ceria content and the porosity of SiO2 carrier possessed great impacts on the structures and catalytic performances of CuO-CeO2/SiO2 catalysts.When appropriate content of CeO2 （Ce content 8 wt%） was added,the catalytic activity was greatly enhanced.In the catalyst supported on silica carrier with larger pore diameter,higher dispersion of CuO was observed,better agglomeration-resistant capacity was displayed and more lattice oxygen could be found,thus the CuO-CeO2 supported on Si-1 showed higher catalytic activity for low-temperature CO oxidation.展开更多
Influence of three different preparation methods, i.e. impregnation, coprecipitation, and inverse coprecipitation, on the preferential oxidation of CO in excess hydrogen （PROX） over CuO-CeO2 catalysts has been inves...Influence of three different preparation methods, i.e. impregnation, coprecipitation, and inverse coprecipitation, on the preferential oxidation of CO in excess hydrogen （PROX） over CuO-CeO2 catalysts has been investigated and CuO-CeO2 catalysts are characterized using BET, XPS, XRD, UV Raman, and TPR techniques. The results show that the catalysts prepared by coprecipitation have smaller particle sizes, well-dispersed CuOx species, more oxygen vacancies, and are more active in the PROX than those prepared by the other methods. However. the inverse coprecipitation depresses the catalytic performance of CuO-CeO2 catalysts and causes the growth of CuO-CeO2 because of different pH value in the precipitation process.展开更多
The pursuit of alternative fuel generation technologies has gained momentum due to the diminishing reserves of fossil fuels and global warming from increased CO_(2)emission.Among the proposed methods,the hydrogenation...The pursuit of alternative fuel generation technologies has gained momentum due to the diminishing reserves of fossil fuels and global warming from increased CO_(2)emission.Among the proposed methods,the hydrogenation of CO_(2)to produce marketable carbon-based products like methanol and ethanol is a practical approach that offers great potential to reduce CO_(2)emissions.Although significant volumes of methanol are currently produced from CO_(2),developing highly efficient and stable catalysts is crucial for further enhancing conversion and selectivity,thereby reducing process costs.An in-depth examination of the differences and similarities in the reaction pathways for methanol and ethanol production highlights the key factors that drive C-C coupling.Identifying these factors guides us toward developing more effective catalysts for ethanol synthesis.In this paper,we explore how different catalysts,through the production of various intermediates,can initiate the synthesis of methanol or ethanol.The catalytic mechanisms proposed by spectroscopic techniques and theoretical calculations,including operando X-ray methods,FTIR analysis,and DFT calculations,are summarized and presented.The following discussion explores the structural properties and composition of catalysts that influence C-C coupling and optimize the conversion rate of CO_(2)into ethanol.Lastly,the review examines recent catalysts employed for selective methanol and ethanol production,focusing on single-atom catalysts.展开更多
Granular CuO-CeO2-MnOx/γ-Al2O3 catalysts were synthesized by the sol-gel method. The performance of the CuO-CeO2-MnOx/γ-Al2O3 catalysts for the selective catalytic reduction (SCR) was studied in a fixed bed system. ...Granular CuO-CeO2-MnOx/γ-Al2O3 catalysts were synthesized by the sol-gel method. The performance of the CuO-CeO2-MnOx/γ-Al2O3 catalysts for the selective catalytic reduction (SCR) was studied in a fixed bed system. Preliminary tests were carried out to analyze the behavior of NH3 and NO over catalyst in the presence of oxygen. The optimum temperature range for SCR over the CuO-CeO2-MnOx/γ-Al2O3 catalysts is 300-400 ℃ . The catalysts maintain nearly 100% NO conversion at 350 ℃. The NH3 oxidation experiments show that both NO and N2O are produced gradually with the increase of temperature. The catalysts in this experiment have a stronger oxidation property on NH3, which improves the denitrification activity at low temperature. The over-oxidation of NH3 at high temperature is the main cause leading to a decrease in the NO conversion. The NH3 and NO desorption experiments show that NH3 and NO can be adsorbed on CuO-CeO2-MnOx/γ-Al2O3 granular catalysts. The transient response of NH3 and NO indicates that the SCR reaction proceeds in accordance with the Eley-Rideal mechanism. The adsorbed NO has little influence on the denitrification activity in SCR process.展开更多
The CuO-CeO2 catalyst prepared by chelating method has a superior catalytic performance for the preferential oxidation of CO in rich hydrogen, compared with the CuO-CeO2 catalyst prepared by coprecipitation method. Th...The CuO-CeO2 catalyst prepared by chelating method has a superior catalytic performance for the preferential oxidation of CO in rich hydrogen, compared with the CuO-CeO2 catalyst prepared by coprecipitation method. The CO conversions over these catalysts, at 120 ℃ and 120000 ml/（g-h） in the absence of CO2 and H2O, are 99.6% and 88.6%, respectively, and the selectivity of O2 over these catalysts is very close （i.e. 51.3% and 55.8%, respectively）. The influence of certain factors such as hydrogen concentration, carbon monoxide concentration, H2O, O2/CO ratios, and space velocity on the catalytic performance of CuO-CeO2 catalyst prepared by chelating method is also studied. The results show that the addition of hydrogen and H2O has a negative effect on the catalytic performance of CuO-CeO2 catalyst, however, the variation of space velocity and the O2/CO ratio causes a comparatively slight influence.展开更多
In the present study, we have investigated the reducibility of CuO species on CuO-CeO2 catalysts and the influence of CuO species on the catalytic performance for CO preferential oxidation （CO PROX） in excess hydrog...In the present study, we have investigated the reducibility of CuO species on CuO-CeO2 catalysts and the influence of CuO species on the catalytic performance for CO preferential oxidation （CO PROX） in excess hydrogen. It is revealed that the smaller the difference of reduction temperature （denoted as ？T） for two adjacent CuO species is, the higher the catalytic activity of CuO-CeO2 for the PROX in excess hydrogen may be obtained. It means that if the reduction energy of Cu0-Cu2＋ pairs matched better, the reduction-oxidation recycle of Cu0-Cu2＋ pairs would go on more easily, then the transferring energy of Cu0-Cu2＋ pairs would be lesser. Therefore, the CuO-CeO2 catalysts will be largely improved in their catalytic performance if the different CuO species on the catalysts have matched the reduction energy, which would allows them to cooperate effectively.展开更多
With ongoing global warming and increasing energy demands,the CH_(4)-CO_(2)reforming reaction(dry reforming of methane,DRM)has garnered significant attention as a promising carbon capture and utilization technology.Ni...With ongoing global warming and increasing energy demands,the CH_(4)-CO_(2)reforming reaction(dry reforming of methane,DRM)has garnered significant attention as a promising carbon capture and utilization technology.Nickel-based catalysts are renowned for their outstanding activity and selectivity in this process.The impact of metal-support interaction(MSI),on Ni-based catalyst performance has been extensively researched and debated recently.This paper reviews the recent research progress of MSI on Ni-based catalysts and their characterization and modulation strategies in catalytic reactions.From the perspective of MSI,the effects of different carriers(metal oxides,carbon materials and molecular sieves,etc.)are introduced on the dispersion and surface structure of Ni active metal particles,and the effect of MSI on the activity and stability of DRM reactions on Ni-based catalysts is discussed in detail.Future research should focus on better understanding and controlling MSI to improve the performance and durability of nickel-based catalysts in CH_(4)-CO_(2)reforming,advancing cleaner energy technologies.展开更多
Electrocatalytic reduction of carbon dioxide(CO_(2))to carbon monoxide(CO)is an effective strategy to achieve carbon neutrality.High selective and low-cost catalysts for the electrocatalytic reduction of CO_(2)have re...Electrocatalytic reduction of carbon dioxide(CO_(2))to carbon monoxide(CO)is an effective strategy to achieve carbon neutrality.High selective and low-cost catalysts for the electrocatalytic reduction of CO_(2)have received increasing attention.In contrast to the conventional tube furnace method,the high-temperature shock(HTS)method enables ultra-fast thermal processing,superior atomic efficiency,and a streamlined synthesis protocol,offering a simplified method for the preparation of high-performance single-atom catalysts(SACs).The reports have shown that nickel-based SACs can be synthesized quickly and conveniently using the HTS method,making their application in CO_(2)reduction reactions(CO_(2)RR)a viable and promising avenue for further exploration.In this study,the effect of heating temperature,metal loading and different nitrogen(N)sources on the catalyst morphology,coordination environment and electrocatalytic performance were investigated.Under optimal conditions,0.05Ni-DCD-C-1050 showed excellent performance in reducing CO_(2)to CO,with CO selectivity close to 100%(−0.7 to−1.0 V vs RHE)and current density as high as 130 mA/cm^(2)(−1.1 V vs RHE)in a flow cell under alkaline environment.展开更多
Owing to outstanding hydrophilicity and ionic interaction,layered double hydroxides(LDHs)have emerged as a promising carrier for high performance catalysts.However,the synthesis of new specialized catalytic LDHs for d...Owing to outstanding hydrophilicity and ionic interaction,layered double hydroxides(LDHs)have emerged as a promising carrier for high performance catalysts.However,the synthesis of new specialized catalytic LDHs for degradation of antibiotics still faces some challenges.In this study,a CoFe_(2)O_(4)/MgAl-LDH composite catalyst was synthesized using a hydrothermal coprecipitation method.Comprehensive characterization reveals that the surface of MgAl-LDH is covered with nanometer CoFe_(2)O_(4) particles.The specific surface area of CoFe_(2)O_(4)/MgAl-LDH is 82.84 m^(2)·g^(-)1,which is 2.34 times that of CoFe_(2)O_(4).CoFe_(2)O_(4)/MgAl-LDH has a saturation magnetic strength of 22.24 A·m^(2)·kg^(-1) facilitating efficient solid-liquid separation.The composite catalyst was employed to activate peroxymonosulfate(PMS)for the efficient degradation of tetracycline hydrochloride(TCH).It is found that the catalytic performance of CoFe_(2)O_(4)/MgAl-LDH significantly exceeds that of CoFe_(2)O_(4).The maximum TCH removal reaches 98.2%under the optimal conditions([TCH]=25 mg/L,[PMS]=1.5 mmol/L,CoFe_(2)O_(4)/MgAl-LDH=0.20 g/L,pH 7,and T=25℃).Coexisting ions in the solution,such as SO_(4)^(2-),Cl-,H_(2)PO_(4)^(-),and CO_(3)^(2-),have a negligible effect on catalytic performance.Cyclic tests demonstrate that the catalytic performance of CoFe_(2)O_(4)/MgAl-LDH remains 67.2%after five cycles.Mechanism investigations suggest that O_(2)^(•-)and ^(1)O_(2) produced by CoFe_(2)O_(4)/MgAl-LDH play a critical role in the catalytic degradation.展开更多
The combination of solar energy and natural hydro-thermal systems will innovate the chemistry ofCO_(2)hydrogenation;however,the approach remains challenging due to the lack of robust and cost-effective catalytic syste...The combination of solar energy and natural hydro-thermal systems will innovate the chemistry ofCO_(2)hydrogenation;however,the approach remains challenging due to the lack of robust and cost-effective catalytic system.Here,Zn which can be recycled with solar energy-induced approach was chosen as the reductant and Co as catalyst to achieve robust hydrothermalCO_(2)methanation.Nanosheets of honeycomb ZnO were grown in situ on the Co surface,resulting in a new motif(Co@ZnO catalyst)that inhibits Co deacti-vation through ZnO-assistedCoOx reduction.The stabilized Co and interaction between Co and ZnO functioned collaboratively toward the full conversion ofCO_(2)–CH_(4).In situ hydrothermal infrared spectros-copy confirmed the formation of formic acid as an intermediate,thereby avoiding CO formation and unwanted side reaction pathways.This study presents a straightforward one-step process for both highly efficientCO_(2)conversion and catalyst synthesis,paving the way for solar-drivenCO_(2)methanation.展开更多
Supported metal catalysts are the backbone of heterogeneous catalysis,playing a crucial role in the modern chemical industry.Metal-support interactions(MSIs)are known important in determining the catalytic performance...Supported metal catalysts are the backbone of heterogeneous catalysis,playing a crucial role in the modern chemical industry.Metal-support interactions(MSIs)are known important in determining the catalytic performance of supported metal catalysts.This is particularly true for single-atom catalysts(SACs)and pseudo-single-atom catalysts(pseudo-SACs),where all metal atoms are dispersed on,and interact directly with the support.Consequently,the MSI of SACs and pseudo-SACs are theoretically more sensitive to modulation compared to that of traditional nanoparticle catalysts.In this work,we experimentally demonstrated this hypothesis by an observed size-dependent MSI modulation.We fabricated CoFe_(2)O_(4) supported Pt pseudo-SACs and nanoparticle catalysts,followed by a straightforward water treatment process.It was found that the covalent strong metal-support interaction(CMSI)in pseudo-SACs can be weakened,leading to a significant activity improvement in methane combustion reaction.This finding aligns with our recent observation of CoFe_(2)O_(4) supported Pt SACs.By contrast,the MSI in Pt nanoparticle catalyst was barely affected by the water treatment,giving rise to almost unchanged catalytic performance.This work highlights the critical role of metal size in determining the MSI modulation,offering a novel strategy for tuning the catalytic performance of SACs and pseudo-SACs by fine-tuning their MSIs.展开更多
Formamide condensation with Ni can generate the N–C structure,widely recognized as an efficient catalyst for electrocatalytic CO_(2) reduction reaction(CO_(2)RR).To improve the utilization efficiency of Ni atoms,we i...Formamide condensation with Ni can generate the N–C structure,widely recognized as an efficient catalyst for electrocatalytic CO_(2) reduction reaction(CO_(2)RR).To improve the utilization efficiency of Ni atoms,we introduced metal oxides as substrates to modulate the growth of a formamide-Ni(FA-Ni)condensate.FA-Ni@TiO_(2) demonstrated 2.8 times higher partial CO current density and Ni turnover frequency than FA-Ni,which were also higher than those of other FA-Ni@metal oxides,including ZrO_(2),Al_(2)O_(3),Fe_(2)O_(3),and ZnO.The improved performance of CO_(2)RR can be attributed to the Ni content exposed on FA-Ni@TiO_(2) being twice that of the raw FA-Ni condensate.The Fourier transform infrared results suggested that formamide was adsorbed on TiO_(2) via the-CHO group,exposing-NH_(2) for potential interaction with Ni.As a result,Ni atoms were predispersed on the TiO_(2) surface.By contrast,the dispersion of Ni atoms was not enhanced by other metal oxides,such as Al_(2)O_(3),Fe_(2)O_(3),and ZnO,owing to the robust acidity of their surface sites.These metal oxides adsorbed formamide via-NH_(2),leading to the absence of extra-NH_(2) available for binding to Ni atoms.This study provides new insights into the development of appropriate substrates for single-atom catalysts.展开更多
The use of fossil fuels significantly contributes to excess CO_(2) emissions.Catalytic hydrogenation of CO_(2) to dimethyl ether(DME)is an effective method for CO_(2) recycling,offering both environmental and economic...The use of fossil fuels significantly contributes to excess CO_(2) emissions.Catalytic hydrogenation of CO_(2) to dimethyl ether(DME)is an effective method for CO_(2) recycling,offering both environmental and economic benefits.Zeolites,known for their efficiency as solid catalysts,are widely utilized in the chemical industries.Bifunctional catalysts based on zeolites have gained attention for their applications in CO_(2) hydrogenation to DME.This review discusses key factors affecting the catalytic performance of zeolites,including topologies,Si/Al ratio,crystal size,and the proximity of metallic species to the zeolite catalysts.Although bifunctional catalytic systems enhance the conversion of CO_(2) to DME,they also lead to high CO selectivity at elevated temperatures,which can limit both DME yield and selectivity.We present recent advancements in the development of bifunctional catalysts for the direct hydrogenation of CO_(2) to DME,providing insights for designing optimized catalysts for tandem reaction systems.展开更多
The role of catalysts in enhancing the hydrogen storage kinetics of the Mg/MgH_(2)system is pivotal.However,the exploration of efficient catalysts and the underlying principles of their design remain both a prominent ...The role of catalysts in enhancing the hydrogen storage kinetics of the Mg/MgH_(2)system is pivotal.However,the exploration of efficient catalysts and the underlying principles of their design remain both a prominent focus and a significant challenge in current research.In this study,we present a bimetallic oxide of Bi_(2)Ti_(2)O_(7)hollow sphere as a highly effective catalyst for MgH_(2).As a result,the Bi_(2)Ti_(2)O_(7)-catalyzed Mg/MgH_(2)system lowers the hydrogen desorption initiation temperature to 194.3℃,reduces the peak desorption temperature to 245.6℃,decreases the dehydrogenation activation energy to 82.14 kJ·mol^(−1),and can absorb 5.4 wt.%of hydrogen within 60 s at 200℃,demonstrating outstanding hydrogen ab/desorption kinetics,compared to pure MgH_(2).Additionally,it can maintain a high hydrogen capacity of 5.2 wt.%,even after 50 dehydrogenation cycles,showing good cycle stability.The characterization results show that the high-valent Bi and Ti in Bi_(2)Ti_(2)O_(7)are reduced to their low-valent or even zero-valent metallic states during the dehydrogenation and hydrogenation process,thus establishing an in-situ multivalent and multi-element catalytic environment.Density functional theory calculations further reveal that the synergistic effects between Bi and Ti in the Bi-Ti mixed oxide facilitate the cleavage of Mg-H bonds and lower the kinetic barrier for the dissociation of hydrogen molecules,thereby substantially enhancing the kinetics of the Mg/MgH_(2)system.This study presents a strategic method for developing efficient catalysts for hydrogen storage materials by harnessing the synergistic effects of metal elements.展开更多
Charge-neutral method(CNM)is extensively used in investigating the performance of catalysts and the mechanism of N_(2)electrochemical reduction(NRR).However,disparities remain between the predicted potentials required...Charge-neutral method(CNM)is extensively used in investigating the performance of catalysts and the mechanism of N_(2)electrochemical reduction(NRR).However,disparities remain between the predicted potentials required for NRR by the CNM methods and those observed experimentally,as the CNM method neglects the charge effect from the electrode potential.To address this issue,we employed the constant electrode potential(CEP)method to screen atomic transition metal-N-graphene(M_(1)/N-graphene)as NRR electrocatalysts and systematically investigated the underlying catalytic mechanism.Among eight types of M_(1)/N-graphene(M_(1)=Mo,W,Fe,Re,Ni,Co,V,Cr),W_(1)/N-graphene emerges as the most promising NRR electrocatalyst with a limiting potential as low as−0.13 V.Additionally,the W_(1)/N-graphene system consistently maintains a positive charge during the reaction due to its Fermi level being higher than that of the electrode.These results better match with the actual circumstances compared to those calculated by conventional CNM method.Thus,our work not only develops a promising electrocatalyst for NRR but also deepens the understanding of the intrinsic electrocatalytic mechanism.展开更多
基金Supported by the National Key Research and Development Program of China(2023YFB4104500,2023YFB4104502)the National Natural Science Foundation of China(22138013)the Taishan Scholar Project(ts201712020).
文摘Against the backdrop of escalating global climate change and energy crises,the resource utilization of carbon dioxide(CO_(2)),a major greenhouse gas,has become a crucial pathway for achieving carbon peaking and carbon neutrality goals.The hydrogenation of CO_(2)to methanol not only enables carbon sequestration and recycling,but also provides a route to produce high value-added fuels and basic chemical feedstocks,holding significant environmental and economic potential.However,this conversion process is thermodynamically and kinetically limited,and traditional catalyst systems(e.g.,Cu/ZnO/Al_(2)O_(3))exhibit inadequate activity,selectivity,and stability under mild conditions.Therefore,the development of novel high-performance catalysts with precisely tunable structures and functionalities is imperative.Metal-organic frameworks(MOFs),as crystalline porous materials with high surface area,tunable pore structures,and diverse metal-ligand compositions,have the great potential in CO_(2)hydrogenation catalysis.Their structural design flexibility allows for the construction of well-dispersed active sites,tailored electronic environments,and enhanced metal-support interactions.This review systematically summarizes the recent advances in MOF-based and MOF-derived catalysts for CO_(2)hydrogenation to methanol,focusing on four design strategies:(1)spatial confinement and in situ construction,(2)defect engineering and ion-exchange,(3)bimetallic synergy and hybrid structure design,and(4)MOF-derived nanomaterial synthesis.These approaches significantly improve CO_(2)conversion and methanol selectivity by optimizing metal dispersion,interfacial structures,and reaction pathways.The reaction mechanism is further explored by focusing on the three main reaction pathways:the formate pathway(HCOO*),the RWGS(Reverse Water Gas Shift reaction)+CO*hydrogenation pathway,and the trans-COOH pathway.In situ spectroscopic studies and density functional theory(DFT)calculations elucidate the formation and transformation of key intermediates,as well as the roles of active sites,metal-support interfaces,oxygen vacancies,and promoters.Additionally,representative catalytic performance data for MOFbased systems are compiled and compared,demonstrating their advantages over traditional catalysts in terms of CO_(2)conversion,methanol selectivity,and space-time yield.Future perspectives for MOF-based CO_(2)hydrogenation catalysts will prioritize two main directions:structural design and mechanistic understanding.The precise construction of active sites through multi-metallic synergy,defect engineering,and interfacial electronic modulation should be made to enhance catalyst selectivity and stability.In addition,advanced in situ characterization techniques combined with theoretical modeling are essential to unravel the detailed reaction mechanisms and intermediate behaviors,thereby guiding rational catalyst design.Moreover,to enable industrial application,challenges related to thermal/hydrothermal stability,catalyst recyclability,and cost-effective large-scale synthesis must be addressed.The development of green,scalable preparation methods and the integration of MOF catalysts into practical reaction systems(e.g.,flow reactors)will be crucial for bridging the gap between laboratory research and commercial deployment.Ultimately,multi-scale structure-performance optimization and catalytic system integration will be vital for accelerating the industrialization of MOF-based CO_(2)-to-methanol technologies.
基金supports from the National Natural Science Foundation of China(Grant Nos.12305372 and 22376217)the National Key Research&Development Program of China(Grant Nos.2022YFA1603802 and 2022YFB3504100)+1 种基金the projects of the key laboratory of advanced energy materials chemistry,ministry of education(Nankai University)key laboratory of Jiangxi Province for persistent pollutants prevention control and resource reuse(2023SSY02061)are gratefully acknowledged.
文摘Using photoelectrocatalytic CO_(2) reduction reaction(CO_(2)RR)to produce valuable fuels is a fascinating way to alleviate environmental issues and energy crises.Bismuth-based(Bi-based)catalysts have attracted widespread attention for CO_(2)RR due to their high catalytic activity,selectivity,excellent stability,and low cost.However,they still need to be further improved to meet the needs of industrial applications.This review article comprehensively summarizes the recent advances in regulation strategies of Bi-based catalysts and can be divided into six categories:(1)defect engineering,(2)atomic doping engineering,(3)organic framework engineering,(4)inorganic heterojunction engineering,(5)crystal face engineering,and(6)alloying and polarization engineering.Meanwhile,the corresponding catalytic mechanisms of each regulation strategy will also be discussed in detail,aiming to enable researchers to understand the structure-property relationship of the improved Bibased catalysts fundamentally.Finally,the challenges and future opportunities of the Bi-based catalysts in the photoelectrocatalytic CO_(2)RR application field will also be featured from the perspectives of the(1)combination or synergy of multiple regulatory strategies,(2)revealing formation mechanism and realizing controllable synthesis,and(3)in situ multiscale investigation of activation pathways and uncovering the catalytic mechanisms.On the one hand,through the comparative analysis and mechanism explanation of the six major regulatory strategies,a multidimensional knowledge framework of the structure-activity relationship of Bi-based catalysts can be constructed for researchers,which not only deepens the atomic-level understanding of catalytic active sites,charge transport paths,and the adsorption behavior of intermediate products,but also provides theoretical guiding principles for the controllable design of new catalysts;on the other hand,the promising collaborative regulation strategies,controllable synthetic paths,and the in situ multiscale characterization techniques presented in this work provides a paradigm reference for shortening the research and development cycle of high-performance catalysts,conducive to facilitating the transition of photoelectrocatalytic CO_(2)RR technology from the laboratory routes to industrial application.
基金supported by the Ministry of Science and Technology of China (No.2004 CB 719504)
文摘High performance CuO-CeO2 catalysts for selective oxidation of CO in excess hydrogen were prepared by a hydrothermal method under different preparation conditions and evaluated for catalytic activities and selectivities. By changing the ^nCTAB/^nCe ratio and hydrothermal aging time, the catalytic activity of the CuO-CeO2 catalysts increased and the operating temperature window, in which the CO conversion was higher than 99%, was widened. XRD results showed no peaks of CuOx species and Cu-Ce-O solid solution were observed. On the other hand, Cu＋ species in the CuO-CeO2 catalysts, which was associated with a strong interaction between copper oxide clusters and cerium oxide and could be favorable for improving the selective oxidation performance of CO in excess H2, were detected by H2-TPR and XPS techniques.
基金supported by the National Basic Research Program of China (2010CB732304)the National Natural Science Foundation of China (21177142 and 20973193)
文摘CuO-CeO2 catalysts were prepared by a urea precipitation method for the oxidative steam reforming of ethanol at low-temperature.The catalytic performance was evaluated and the catalysts were characterized by inductively coupled plasma atomic emission spectroscopy,X-ray diffraction,temperature-programmed reduction,field emission scanning electron microscopy and thermo-gravimetric analysis.Over CuOCeO2 catalysts,H2 with low CO content was produced in the whole tested temperature range of 250–450 C.The non-noble metal catalyst 20CuCe showed higher H2production rate than 1%Rh/CeO2 catalyst at 300–400 C and the advantage was more obvious after 20 h testing at400 C.These results further confirmed that CuO-CeO2 catalysts may be suitable candidates for low temperature hydrogen production from ethanol.
基金supported by the National Natural Science Foundation of China(20590360)New Century Excellent Talent Project of China(NCET-05-0783)
文摘The effects of CeO2 contents and silica carrier porosity with their pore diameters ranging from 5.2 nm to 12.5 nm of CuO-CeO2/SiO2 cata-lysts in CO oxidation were investigated.The catalysts were characterized by N2 adsorption/desorption at low temperature,X-ray diffraction （XRD）,temperature-programmed reduction by H2 （H2-TPR）,oxygen temperature programmed desorption （O2-TPD） and X-ray photoelectron spectroscopy （XPS）.The results suggested that,the ceria content and the porosity of SiO2 carrier possessed great impacts on the structures and catalytic performances of CuO-CeO2/SiO2 catalysts.When appropriate content of CeO2 （Ce content 8 wt%） was added,the catalytic activity was greatly enhanced.In the catalyst supported on silica carrier with larger pore diameter,higher dispersion of CuO was observed,better agglomeration-resistant capacity was displayed and more lattice oxygen could be found,thus the CuO-CeO2 supported on Si-1 showed higher catalytic activity for low-temperature CO oxidation.
文摘Influence of three different preparation methods, i.e. impregnation, coprecipitation, and inverse coprecipitation, on the preferential oxidation of CO in excess hydrogen （PROX） over CuO-CeO2 catalysts has been investigated and CuO-CeO2 catalysts are characterized using BET, XPS, XRD, UV Raman, and TPR techniques. The results show that the catalysts prepared by coprecipitation have smaller particle sizes, well-dispersed CuOx species, more oxygen vacancies, and are more active in the PROX than those prepared by the other methods. However. the inverse coprecipitation depresses the catalytic performance of CuO-CeO2 catalysts and causes the growth of CuO-CeO2 because of different pH value in the precipitation process.
基金the Canadian NRCan OERD Energy Innovation Programthe Natural Sciences and Engineering Research Council of Canada,and the Carbon Solution Program for their financial support.
文摘The pursuit of alternative fuel generation technologies has gained momentum due to the diminishing reserves of fossil fuels and global warming from increased CO_(2)emission.Among the proposed methods,the hydrogenation of CO_(2)to produce marketable carbon-based products like methanol and ethanol is a practical approach that offers great potential to reduce CO_(2)emissions.Although significant volumes of methanol are currently produced from CO_(2),developing highly efficient and stable catalysts is crucial for further enhancing conversion and selectivity,thereby reducing process costs.An in-depth examination of the differences and similarities in the reaction pathways for methanol and ethanol production highlights the key factors that drive C-C coupling.Identifying these factors guides us toward developing more effective catalysts for ethanol synthesis.In this paper,we explore how different catalysts,through the production of various intermediates,can initiate the synthesis of methanol or ethanol.The catalytic mechanisms proposed by spectroscopic techniques and theoretical calculations,including operando X-ray methods,FTIR analysis,and DFT calculations,are summarized and presented.The following discussion explores the structural properties and composition of catalysts that influence C-C coupling and optimize the conversion rate of CO_(2)into ethanol.Lastly,the review examines recent catalysts employed for selective methanol and ethanol production,focusing on single-atom catalysts.
基金Projects (50776037,50721005) supported by the National Natural Science Foundation of China
文摘Granular CuO-CeO2-MnOx/γ-Al2O3 catalysts were synthesized by the sol-gel method. The performance of the CuO-CeO2-MnOx/γ-Al2O3 catalysts for the selective catalytic reduction (SCR) was studied in a fixed bed system. Preliminary tests were carried out to analyze the behavior of NH3 and NO over catalyst in the presence of oxygen. The optimum temperature range for SCR over the CuO-CeO2-MnOx/γ-Al2O3 catalysts is 300-400 ℃ . The catalysts maintain nearly 100% NO conversion at 350 ℃. The NH3 oxidation experiments show that both NO and N2O are produced gradually with the increase of temperature. The catalysts in this experiment have a stronger oxidation property on NH3, which improves the denitrification activity at low temperature. The over-oxidation of NH3 at high temperature is the main cause leading to a decrease in the NO conversion. The NH3 and NO desorption experiments show that NH3 and NO can be adsorbed on CuO-CeO2-MnOx/γ-Al2O3 granular catalysts. The transient response of NH3 and NO indicates that the SCR reaction proceeds in accordance with the Eley-Rideal mechanism. The adsorbed NO has little influence on the denitrification activity in SCR process.
基金The work was supported by the National Basic Research Program of China (973 Program, No. 2004CB719504)
文摘The CuO-CeO2 catalyst prepared by chelating method has a superior catalytic performance for the preferential oxidation of CO in rich hydrogen, compared with the CuO-CeO2 catalyst prepared by coprecipitation method. The CO conversions over these catalysts, at 120 ℃ and 120000 ml/（g-h） in the absence of CO2 and H2O, are 99.6% and 88.6%, respectively, and the selectivity of O2 over these catalysts is very close （i.e. 51.3% and 55.8%, respectively）. The influence of certain factors such as hydrogen concentration, carbon monoxide concentration, H2O, O2/CO ratios, and space velocity on the catalytic performance of CuO-CeO2 catalyst prepared by chelating method is also studied. The results show that the addition of hydrogen and H2O has a negative effect on the catalytic performance of CuO-CeO2 catalyst, however, the variation of space velocity and the O2/CO ratio causes a comparatively slight influence.
基金supported by the State Key Laboratory of Heavy Oil Processing (No. 200803)the Ministry of Science and Technology of China (No.2005CB221406)
文摘In the present study, we have investigated the reducibility of CuO species on CuO-CeO2 catalysts and the influence of CuO species on the catalytic performance for CO preferential oxidation （CO PROX） in excess hydrogen. It is revealed that the smaller the difference of reduction temperature （denoted as ？T） for two adjacent CuO species is, the higher the catalytic activity of CuO-CeO2 for the PROX in excess hydrogen may be obtained. It means that if the reduction energy of Cu0-Cu2＋ pairs matched better, the reduction-oxidation recycle of Cu0-Cu2＋ pairs would go on more easily, then the transferring energy of Cu0-Cu2＋ pairs would be lesser. Therefore, the CuO-CeO2 catalysts will be largely improved in their catalytic performance if the different CuO species on the catalysts have matched the reduction energy, which would allows them to cooperate effectively.
基金supported by the Natural Science Foundation of Shanxi Province(202203021221155)the Foundation of National Key Laboratory of High Efficiency and Low Carbon Utilization of Coal(J23-24-902)。
文摘With ongoing global warming and increasing energy demands,the CH_(4)-CO_(2)reforming reaction(dry reforming of methane,DRM)has garnered significant attention as a promising carbon capture and utilization technology.Nickel-based catalysts are renowned for their outstanding activity and selectivity in this process.The impact of metal-support interaction(MSI),on Ni-based catalyst performance has been extensively researched and debated recently.This paper reviews the recent research progress of MSI on Ni-based catalysts and their characterization and modulation strategies in catalytic reactions.From the perspective of MSI,the effects of different carriers(metal oxides,carbon materials and molecular sieves,etc.)are introduced on the dispersion and surface structure of Ni active metal particles,and the effect of MSI on the activity and stability of DRM reactions on Ni-based catalysts is discussed in detail.Future research should focus on better understanding and controlling MSI to improve the performance and durability of nickel-based catalysts in CH_(4)-CO_(2)reforming,advancing cleaner energy technologies.
基金supported by the National Key R&D Program of China(2024YFB4106400)National Natural Science Foundation of China(22209200,52302331)。
文摘Electrocatalytic reduction of carbon dioxide(CO_(2))to carbon monoxide(CO)is an effective strategy to achieve carbon neutrality.High selective and low-cost catalysts for the electrocatalytic reduction of CO_(2)have received increasing attention.In contrast to the conventional tube furnace method,the high-temperature shock(HTS)method enables ultra-fast thermal processing,superior atomic efficiency,and a streamlined synthesis protocol,offering a simplified method for the preparation of high-performance single-atom catalysts(SACs).The reports have shown that nickel-based SACs can be synthesized quickly and conveniently using the HTS method,making their application in CO_(2)reduction reactions(CO_(2)RR)a viable and promising avenue for further exploration.In this study,the effect of heating temperature,metal loading and different nitrogen(N)sources on the catalyst morphology,coordination environment and electrocatalytic performance were investigated.Under optimal conditions,0.05Ni-DCD-C-1050 showed excellent performance in reducing CO_(2)to CO,with CO selectivity close to 100%(−0.7 to−1.0 V vs RHE)and current density as high as 130 mA/cm^(2)(−1.1 V vs RHE)in a flow cell under alkaline environment.
基金University Synergy Innovation Program of Anhui Province(GXXT-2022-083)Science and Technology Plan Project of Wuhu City,China(2023kx12)Anhui Provincial Department of Education New Era Education Project(2023xscx070)。
文摘Owing to outstanding hydrophilicity and ionic interaction,layered double hydroxides(LDHs)have emerged as a promising carrier for high performance catalysts.However,the synthesis of new specialized catalytic LDHs for degradation of antibiotics still faces some challenges.In this study,a CoFe_(2)O_(4)/MgAl-LDH composite catalyst was synthesized using a hydrothermal coprecipitation method.Comprehensive characterization reveals that the surface of MgAl-LDH is covered with nanometer CoFe_(2)O_(4) particles.The specific surface area of CoFe_(2)O_(4)/MgAl-LDH is 82.84 m^(2)·g^(-)1,which is 2.34 times that of CoFe_(2)O_(4).CoFe_(2)O_(4)/MgAl-LDH has a saturation magnetic strength of 22.24 A·m^(2)·kg^(-1) facilitating efficient solid-liquid separation.The composite catalyst was employed to activate peroxymonosulfate(PMS)for the efficient degradation of tetracycline hydrochloride(TCH).It is found that the catalytic performance of CoFe_(2)O_(4)/MgAl-LDH significantly exceeds that of CoFe_(2)O_(4).The maximum TCH removal reaches 98.2%under the optimal conditions([TCH]=25 mg/L,[PMS]=1.5 mmol/L,CoFe_(2)O_(4)/MgAl-LDH=0.20 g/L,pH 7,and T=25℃).Coexisting ions in the solution,such as SO_(4)^(2-),Cl-,H_(2)PO_(4)^(-),and CO_(3)^(2-),have a negligible effect on catalytic performance.Cyclic tests demonstrate that the catalytic performance of CoFe_(2)O_(4)/MgAl-LDH remains 67.2%after five cycles.Mechanism investigations suggest that O_(2)^(•-)and ^(1)O_(2) produced by CoFe_(2)O_(4)/MgAl-LDH play a critical role in the catalytic degradation.
基金the National Natural Science Foundation of China(No.22108171)the Shanghai Key Laboratory of Hydrogen Science&Center of Hydrogen Science,Shanghai Jiao Tong University,China.
文摘The combination of solar energy and natural hydro-thermal systems will innovate the chemistry ofCO_(2)hydrogenation;however,the approach remains challenging due to the lack of robust and cost-effective catalytic system.Here,Zn which can be recycled with solar energy-induced approach was chosen as the reductant and Co as catalyst to achieve robust hydrothermalCO_(2)methanation.Nanosheets of honeycomb ZnO were grown in situ on the Co surface,resulting in a new motif(Co@ZnO catalyst)that inhibits Co deacti-vation through ZnO-assistedCoOx reduction.The stabilized Co and interaction between Co and ZnO functioned collaboratively toward the full conversion ofCO_(2)–CH_(4).In situ hydrothermal infrared spectros-copy confirmed the formation of formic acid as an intermediate,thereby avoiding CO formation and unwanted side reaction pathways.This study presents a straightforward one-step process for both highly efficientCO_(2)conversion and catalyst synthesis,paving the way for solar-drivenCO_(2)methanation.
文摘Supported metal catalysts are the backbone of heterogeneous catalysis,playing a crucial role in the modern chemical industry.Metal-support interactions(MSIs)are known important in determining the catalytic performance of supported metal catalysts.This is particularly true for single-atom catalysts(SACs)and pseudo-single-atom catalysts(pseudo-SACs),where all metal atoms are dispersed on,and interact directly with the support.Consequently,the MSI of SACs and pseudo-SACs are theoretically more sensitive to modulation compared to that of traditional nanoparticle catalysts.In this work,we experimentally demonstrated this hypothesis by an observed size-dependent MSI modulation.We fabricated CoFe_(2)O_(4) supported Pt pseudo-SACs and nanoparticle catalysts,followed by a straightforward water treatment process.It was found that the covalent strong metal-support interaction(CMSI)in pseudo-SACs can be weakened,leading to a significant activity improvement in methane combustion reaction.This finding aligns with our recent observation of CoFe_(2)O_(4) supported Pt SACs.By contrast,the MSI in Pt nanoparticle catalyst was barely affected by the water treatment,giving rise to almost unchanged catalytic performance.This work highlights the critical role of metal size in determining the MSI modulation,offering a novel strategy for tuning the catalytic performance of SACs and pseudo-SACs by fine-tuning their MSIs.
基金supported by the National Natural Science Foundation of China(No.42077299)the Innovation Program of Chinese Academy of Agricultural Sciences(No.Y2024QC29).
文摘Formamide condensation with Ni can generate the N–C structure,widely recognized as an efficient catalyst for electrocatalytic CO_(2) reduction reaction(CO_(2)RR).To improve the utilization efficiency of Ni atoms,we introduced metal oxides as substrates to modulate the growth of a formamide-Ni(FA-Ni)condensate.FA-Ni@TiO_(2) demonstrated 2.8 times higher partial CO current density and Ni turnover frequency than FA-Ni,which were also higher than those of other FA-Ni@metal oxides,including ZrO_(2),Al_(2)O_(3),Fe_(2)O_(3),and ZnO.The improved performance of CO_(2)RR can be attributed to the Ni content exposed on FA-Ni@TiO_(2) being twice that of the raw FA-Ni condensate.The Fourier transform infrared results suggested that formamide was adsorbed on TiO_(2) via the-CHO group,exposing-NH_(2) for potential interaction with Ni.As a result,Ni atoms were predispersed on the TiO_(2) surface.By contrast,the dispersion of Ni atoms was not enhanced by other metal oxides,such as Al_(2)O_(3),Fe_(2)O_(3),and ZnO,owing to the robust acidity of their surface sites.These metal oxides adsorbed formamide via-NH_(2),leading to the absence of extra-NH_(2) available for binding to Ni atoms.This study provides new insights into the development of appropriate substrates for single-atom catalysts.
基金the National Key Research and Development Program of China(2021YFA1500401)the National Natural Science Foundation of China(22288101)the‘111 Center’(B17020)for supporting this work.
文摘The use of fossil fuels significantly contributes to excess CO_(2) emissions.Catalytic hydrogenation of CO_(2) to dimethyl ether(DME)is an effective method for CO_(2) recycling,offering both environmental and economic benefits.Zeolites,known for their efficiency as solid catalysts,are widely utilized in the chemical industries.Bifunctional catalysts based on zeolites have gained attention for their applications in CO_(2) hydrogenation to DME.This review discusses key factors affecting the catalytic performance of zeolites,including topologies,Si/Al ratio,crystal size,and the proximity of metallic species to the zeolite catalysts.Although bifunctional catalytic systems enhance the conversion of CO_(2) to DME,they also lead to high CO selectivity at elevated temperatures,which can limit both DME yield and selectivity.We present recent advancements in the development of bifunctional catalysts for the direct hydrogenation of CO_(2) to DME,providing insights for designing optimized catalysts for tandem reaction systems.
基金supported by the National Key Research and Development Program of China(No.2024YFB4007204,2022YFB4004301)the National Natural Science Founda-tion of China(Grant Nos.52477220,52301287,22005353)+2 种基金the Two-chain Integration Key Project of Shaanxi Province(2021LLRH-09)the Key Research and Development Program of Shaanxi Province(No.2024CY2-GJHX-44,2024CY2-GJHX-53,2024GX-ZDCYL-04-06)the Key Industrial Chain Technology Research Program of Xi’an city(23LL-RHZDZX0017).
文摘The role of catalysts in enhancing the hydrogen storage kinetics of the Mg/MgH_(2)system is pivotal.However,the exploration of efficient catalysts and the underlying principles of their design remain both a prominent focus and a significant challenge in current research.In this study,we present a bimetallic oxide of Bi_(2)Ti_(2)O_(7)hollow sphere as a highly effective catalyst for MgH_(2).As a result,the Bi_(2)Ti_(2)O_(7)-catalyzed Mg/MgH_(2)system lowers the hydrogen desorption initiation temperature to 194.3℃,reduces the peak desorption temperature to 245.6℃,decreases the dehydrogenation activation energy to 82.14 kJ·mol^(−1),and can absorb 5.4 wt.%of hydrogen within 60 s at 200℃,demonstrating outstanding hydrogen ab/desorption kinetics,compared to pure MgH_(2).Additionally,it can maintain a high hydrogen capacity of 5.2 wt.%,even after 50 dehydrogenation cycles,showing good cycle stability.The characterization results show that the high-valent Bi and Ti in Bi_(2)Ti_(2)O_(7)are reduced to their low-valent or even zero-valent metallic states during the dehydrogenation and hydrogenation process,thus establishing an in-situ multivalent and multi-element catalytic environment.Density functional theory calculations further reveal that the synergistic effects between Bi and Ti in the Bi-Ti mixed oxide facilitate the cleavage of Mg-H bonds and lower the kinetic barrier for the dissociation of hydrogen molecules,thereby substantially enhancing the kinetics of the Mg/MgH_(2)system.This study presents a strategic method for developing efficient catalysts for hydrogen storage materials by harnessing the synergistic effects of metal elements.
基金Natural Science Foundation of Guangdong Province(No.2024A1515011094(C.Q Sun))National Natural Science Foundation of China(Nos.12304243(H.X.Fang),12150100(B.Wang))is gratefully acknowledged。
文摘Charge-neutral method(CNM)is extensively used in investigating the performance of catalysts and the mechanism of N_(2)electrochemical reduction(NRR).However,disparities remain between the predicted potentials required for NRR by the CNM methods and those observed experimentally,as the CNM method neglects the charge effect from the electrode potential.To address this issue,we employed the constant electrode potential(CEP)method to screen atomic transition metal-N-graphene(M_(1)/N-graphene)as NRR electrocatalysts and systematically investigated the underlying catalytic mechanism.Among eight types of M_(1)/N-graphene(M_(1)=Mo,W,Fe,Re,Ni,Co,V,Cr),W_(1)/N-graphene emerges as the most promising NRR electrocatalyst with a limiting potential as low as−0.13 V.Additionally,the W_(1)/N-graphene system consistently maintains a positive charge during the reaction due to its Fermi level being higher than that of the electrode.These results better match with the actual circumstances compared to those calculated by conventional CNM method.Thus,our work not only develops a promising electrocatalyst for NRR but also deepens the understanding of the intrinsic electrocatalytic mechanism.
