The efficient storage and release of H_(2)are pivotal for the advancement of hydrogen energy technologies.Cyclohexane,as a promising liquid organic hydrogen carrier(LOHC),provides a safe and practical solution for H_(...The efficient storage and release of H_(2)are pivotal for the advancement of hydrogen energy technologies.Cyclohexane,as a promising liquid organic hydrogen carrier(LOHC),provides a safe and practical solution for H_(2)storage.However,the performance limitations of dehydrogenation catalysts have hindered the rapid development of LOHC technology.In this study,we successfully developed boron-modified Pt/ZrO_(2)catalysts,which exhibit exceptional catalytic performance in cyclohexane dehydrogenation.The optimal boron content is determined to be 0.5 wt.%,with the Pt/0.5B–ZrO_(2)catalyst achieving high turnover frequency(TOF)of 10,627.3 mol_(H_(2))·mol_(Pt)^(−1)·h^(−1)and benzene selectivity of 99%at 295°C.The catalyst also demonstrates H_(2)evolution rate of 908 mmol·g_(Pt)^(−1)·min^(−1)and low deactivation rate of 0.0043 h^(−1).Remarkably,the catalyst displays outstanding stability and regeneration performance,maintaining its activity without significant loss during a 60-h dehydrogenation reaction and retaining a cyclohexane conversion of 77.2%after 10 consecutive cycles.Comprehensive characterization techniques,including XPS,CO-FTIR,NH_(3)-TPD,H_(2)-TPD,Benzene-TPD,and Py-IR,reveals that boron modification reduces the electron density of Pt,generating abundant electron-deficient Pt atoms.These electron-deficient Pt atoms enhance H_(2)adsorption and accelerate benzene desorption,effectively preventing coke formation from deep benzene dehydrogenation,which is responsible for the high catalytic performance of the Pt/0.5B–ZrO_(2)catalyst.These findings offer a valuable strategy for optimizing dehydrogenation catalysts in LOHC technologies,addressing a critical bottleneck in the development of this essential energy storage solution.展开更多
Propylene,a pivotal chemical feedstock,is extensively used in synthesizing high-value derivatives such as polypropylene and acrylonitrile[1].Although propylene is predominantly produced via naphtha cracking,a persiste...Propylene,a pivotal chemical feedstock,is extensively used in synthesizing high-value derivatives such as polypropylene and acrylonitrile[1].Although propylene is predominantly produced via naphtha cracking,a persistent supply-demand gap exists[2].Non-oil routes,such as propane dehydrogenation(PDH),are increasingly attractive,particularly with the availability of shale gas[3].Modern non-oxidative PDH heavily relies on Pt nanoparticle catalysts promoted with SnOx(e.g.,PtSn/Al2O3 used in Honeywell UOP's Oleflex process)[4].However,these systems suffer from inherent limitations:high Pt costs,coke formation via deep dehydrogenation,and sintering during regeneration-necessitating environmentally detrimental oxychlorination treatments to restore activity[5].展开更多
The dehydrogenation of alkanes has emerged as a vital complementary process to address the increasing global demand for olefins.A key challenge remains in the construction of novel active centers that offer superior a...The dehydrogenation of alkanes has emerged as a vital complementary process to address the increasing global demand for olefins.A key challenge remains in the construction of novel active centers that offer superior activity,stability,and cost-effectiveness.Herein,tricoordinated cobalt atoms were successfully fabricated through an in-situ ligand-protected synthesis by introducing tungsten atoms into zeolite frameworks.These unsaturated Co species efficiently activate C-H bonds while suppressing C-C bond cleavage,resulting in exceptional catalytic activity and olefin selectivity in both propane and ethane dehydrogenation reactions.The optimized Co_(0.2%)@0.01W-S-1 catalyst demonstrated an impressive propylene formation rate of 15.2 molC_(3H6)gcC h^(-1)at 823 K and an ethylene formation rate of 240.3mol_(C2H4)g_(Co)^(-1)h^(-1)at 913 K,with propylene and ethylene selectivities of 99.0%and 97.5%,respectively.These results not only significantly surpass conventional tetracoordinated Co catalysts but also rival some Pt-based catalysts under similar conditions.Importantly,the catalyst exhibited excellent stability in dehydrogenation reactions,with no significant loss in catalytic activity after five consecutive regeneration cycles.This work offers valuable insights into the design of zeolite-supported non-precious metal catalysts with high activity and durability for efficient alkane dehydrogenation.展开更多
Herein,we report the multi-metal atomic catalysts for solid-state dehydrogenation of MgH_(2).It aims to reveal the multi-element synergy in catalysts for solid-state hydrogen storage.The kinetic measurements and fitti...Herein,we report the multi-metal atomic catalysts for solid-state dehydrogenation of MgH_(2).It aims to reveal the multi-element synergy in catalysts for solid-state hydrogen storage.The kinetic measurements and fitting reveal two mechanisms:one shows a maximum rate at the early stage,such as V and Cr;the other needs a temperature-sensitive preparation time for its maximum rate,such as Ni.The combina-tion of two catalyst components demonstrates the best kinetics:V and Cr boost the initial dehydrogena-tion,and Ni benefits the further hydrogen transfer which alleviates the rate of decay.This work provides guidelines for the design of multi-element doped catalysts for MgH_(2) dehydrogenation.展开更多
Non-oxidative dehydrogenation of propane(PDH)is an important route for large-scale on purpose propene production.Although cobalt-based catalysts are promising alternatives to currently used platinum-or chromium oxide-...Non-oxidative dehydrogenation of propane(PDH)is an important route for large-scale on purpose propene production.Although cobalt-based catalysts are promising alternatives to currently used platinum-or chromium oxide-based catalysts,their further developments are hindered by the uncertainties related to the kind of the active sites involved in the desired and side reactions.To contribute to closing such a gap,we systematically investigate the role of oxidized CoO_(x) and metallic Co0 species in the PDH reaction over catalysts based in Silicalite-1 with supported CoO_(x) species differing in their redox properties.C_(3)H_(8) pulse experiments with sub-millisecond and second resolution at pulse sizes of about 13 and 2200 nmol,respectively,combined with in-depth catalyst characterization and PDH tests at different propane conversions enabled us to understand how the reaction-induced reduction of CoO_(x) affects product selectivity.Propane readily reacts with CoO_(x) to yield propene,carbon oxides and water.The formed Co0 species show high activity to coking and cracking reactions.However,if the size of such species is below 2 nm,these undesired reactions are significantly hindered due to the coverage of the active sites by carbon-containing species.The remaining uncovered surface Co0 sites selectively dehydrogenate propane to propene.The best-performing catalyst showed higher activity than a commercial-like K-CrOx/Al_(2)O_(3) and operated durable in a series of 10 dehydrogenation/regeneration cycles under industrial relevant conditions.The space time yield of propene formation of 0.97 kg·h^(-1)·kgcat^(-1) was achieved at 550℃,52%equilibrium propane conversion and 95% propene selectivity.展开更多
Modifying the electronic density of states and the synergistic effect of the active centers by introducing a second metal present an efficient strategy to tune physi/chemi-sorption,probably lead to improving catalytic...Modifying the electronic density of states and the synergistic effect of the active centers by introducing a second metal present an efficient strategy to tune physi/chemi-sorption,probably lead to improving catalytic performances.Herein,bimetallic Ni_(3)Mo/Al_(2)O_(3)catalyst was demonstrated and exhibited over 5 times more active than Pt/Al_(2)O_(3)toward the ethane dehydrogenation(EDH)as well as 2-10 times activity enhancement compared with their monometallic Ni and Mo counterparts and other Ni-based bimetallic nanoparticles.Kinetic studies revealed that the activation energy over Ni_(3)Mo/Al_(2)O_(3)(111 kJ mol^(-1))was much lower than that of Ni(157 kJ mol^(-1))and Mo(171 kJ·mol^(-1)).DFT calculations showed ethane was adsorbed on the Ni or Mo surface in a more parallel configuration,whereas over Ni_(3)Mo it adopted an inclined configuration.This change promoted ethane adsorption and pre-activation of the C-H bond,thereby benefiting the ethane dehydrogenation process on the Ni_(3)Mo surface.展开更多
Propane dehydrogenation(PDH)has emerged as a key on-purpose technology for the production of propylene,but it often depends on toxic chromium and expensive platinum catalysts,highlighting the need for environmentally ...Propane dehydrogenation(PDH)has emerged as a key on-purpose technology for the production of propylene,but it often depends on toxic chromium and expensive platinum catalysts,highlighting the need for environmentally friendly and cost-effective alternatives.In this study,we developed a facile impregnation method to fabricate unsaturated Co single-atoms with a tricoordinated Co_(1)O_(3)H_(x) structure by regulating silanol nests in purely siliceous Beta zeolites.Detailed PDH catalytic tests and characterizations revealed a positive correlation between the presence of silanol nests and enhanced catalytic activity.Additionally,the unsaturated Co single-atoms exhibited a carbon deposition rate more than an order of magnitude slower than that of Co nanoparticles.Notably,the optimized Co_(0.3%)/deAl-meso-Beta catalyst achieved a record-high propylene formation rate of 21.2 mmol_(C3H6) g_(cat)^(-1) h^(-1),with an exceptional propylene selectivity of 99.1%at 550℃.Moreover,the Co_(0.3%)/deAl-meso-Beta catalyst demonstrated excellent stability,with negligible deactivation after 5 consecutive regeneration cycles.This study emphasizes the pivotal role of silanol nests of zeolites in stabilizing and modulating the coordination environment of metallic active sites,providing valuable insights for the design of high-activity,high-stability,and low-cost PDH catalysts.展开更多
In response to the increasing demand of ethylene,electrochemical ethane nonoxidative dehydrogenation(EENDH)to ethylene by protonic ceramic electrolysis cells(PCECs)is developed.However,existing anode materials exhibit...In response to the increasing demand of ethylene,electrochemical ethane nonoxidative dehydrogenation(EENDH)to ethylene by protonic ceramic electrolysis cells(PCECs)is developed.However,existing anode materials exhibit poor proton conductivity and limited catalytic activity.Herein,a novel Sr_(1.95)Fe_(1.4)Co_(0.1)Mo_(0.4)Zr_(0.1)O_(6-δ)(SFCMZ)anode is prepared as PCECs anode for EENDH.Zr doping increases the oxygen vacancies and enhances the proton conductivity of SFCMZ.Moreover,an alloy-oxide heterostructure(Co Fe@SFCMZ)is formed through in-situ exsolution of Co Fe alloy nanoparticles under reduction conditions,generating abundant oxygen vacancies and improving its catalytic activity.Co Fe@SFCMZ cell achieves an electrolysis current density of 0.87 A/cm^(2) at 700℃ under 1.6 V,with an ethane conversion rate of 34.22%and corresponding ethylene selectivity of 93.4%.These results demonstrate that Co Fe@SFCMZ anode exhibits excellent electrocatalytic activity,suggesting promising applications for EENDH.展开更多
Supported metal oxide catalysts have garnered significantattention in oxidative dehydrogenation(ODH)due to their tunable metal-support interactions.The pentacoordinate Al^(3+)(Al_(V)^(3+))in γ-Al_(2)O_(3)supports pla...Supported metal oxide catalysts have garnered significantattention in oxidative dehydrogenation(ODH)due to their tunable metal-support interactions.The pentacoordinate Al^(3+)(Al_(V)^(3+))in γ-Al_(2)O_(3)supports plays a pivotal role in modulating metal-support interaction.This study investigates oxalic acid(OA)pretreatment as a defect engineering strategy to enhance the catalytic performance of CeO_(2)/γ-Al_(2)O_(3)in cyclohexane ODH.Through integrated characterization(XRD,27Al MAS NMR,H_(2)-TPR,TPRO,MS,XPS)and catalytic testing,we demonstrate that optimal OA treatment(1:10 ratio)eliminates 100%of surface Al_(V)^(3+)defects while enhancing CeO_(2)crystallinity and interfacial oxygen mobility.The removal of Al_(V)^(3+)species restructures metal-support interaction,accelerating interfacial oxygen mobility.In oxidation dehydrogenation of cyclohexane,the modified CeO_(2)/γ-Al_(2)O_(3)achieves 29%of cyclohexane conversion with stable selectivity of 49%cyclohexene.These findingsprovide an initial framework for designing redox-active catalysts via targeted support modificationin CeO_(2)/γ-Al_(2)O_(3)systems,emphasizing the relationship between metal-support interaction and oxygen mobility.展开更多
Recent studies have revealed the extraordinary performance of zirconium oxide in propane dehydrogenation,which is attributed to the excellent reactivity of the coordinatively unsaturated zirconium sites(Zr_(cus))aroun...Recent studies have revealed the extraordinary performance of zirconium oxide in propane dehydrogenation,which is attributed to the excellent reactivity of the coordinatively unsaturated zirconium sites(Zr_(cus))around the oxygen vacancies.The origin of the enhanced catalytic activity of ZrO_(2)with defective tetrahedral Zr sites was examined by direct comparison with its pristine counterpart in the current study.Electronic-structure analysis revealed that electrons from oxygen removal were localized within vacancies on the defective surface,which directly attacked the C-H bond in propane.The involvement of localized electrons activates the C-H bond via back-donation to the antibonding orbital on the defective surface;conversely,charge is transferred from propane to the pristine surfaces.The barrier for the first C-H bond activation is clearly significantly reduced on the defective surfaces compared to that on the pristine surfaces,which verifies the superior activity of Zr_(cus).Notably,however,the desorption of both propene and hydrogen molecules from Zr_(cus)is more difficult due to strong binding.The calculated turnover frequency(TOF)for propene formation demonstrates that the pristine surfaces exhibit better catalytic performance at lower temperatures,whereas the defective surfaces have a larger TOF at high temperatures.However,the rate-determining step and reaction order on the defective surface differ from those on the pristine surface,which corroborates that the catalysts follow different mechanisms.A further optimization strategy was proposed to address the remaining bottlenecks in propane dehydrogenation on zirconium oxide.展开更多
The oxidative dehydrogenation of propane to propylene using CO_(2)(CO_(2)-ODH)offers a promising route for both propylene production and CO_(2)utilization.In this study,we investigate the effect of alkali metal doping...The oxidative dehydrogenation of propane to propylene using CO_(2)(CO_(2)-ODH)offers a promising route for both propylene production and CO_(2)utilization.In this study,we investigate the effect of alkali metal doping on Pt-based catalysts in CO_(2)-ODH reactions.The optimized 0.1 KPt/S-1 catalyst achieved a high propane conversion of 48.3%,propylene selectivity of 85.5%,and CO_(2)conversion of 19.1%at a low temperature of 500℃with the Pt loading of 0.2 wt%and K loading of 0.1 wt%respectively.Characterization techniques,including high-resolution transmission electron microscope(HR-TEM),CO-diffuse reflectance infrared Fourier transform spectroscopy(CO-DRIFTS),X-ray absorption fine structure(XAFS),and X-ray Photoelectron Spectroscopy(XPS),revealed that the doping of K with Pt led to a strong interaction between potassium and platinum(Pt-KO_(x)cluster).This interaction resulted in a reduction of Pt particle size and a local enrichment of electron density around Pt atoms.These structural modifications improved the anchoring of Pt nanoparticles and enhanced Pt atom dispersion,thereby enhancing the activity of the catalyst and minimizing side reactions.Additionally,pyridine infrared(Py-IR)and temperature-programmed desorption(TPD)studies demonstrated that the prepared0.1 KPt/S-1 catalyst exhibited optimal acidity,which promoted C–H activation and facilitated the efficient adsorption and activation of CO_(2).These dual effects significantly lowered the activation energy for CO_(2)-ODH,enabling efficient dehydrogenation to propylene at a lower temperature of 500℃.This work highlights the critical role of alkali metal doping in modifying the electronic properties of Pt and optimizing catalyst acidity,which collectively contribute to the enhanced performance of the 0.1 KPt/S-1 catalyst.These findings offer valuable insights into the mechanistic pathway of CO_(2)-ODH and provide a foundation for the rational design of high-performance dehydrogenation catalysts.展开更多
Dispersing metals from nanoparticles to clusters is often achieved using ligand protection methods,which exhibit unique properties such as suppressing structure-sensitive side reactions.However,this method is limited ...Dispersing metals from nanoparticles to clusters is often achieved using ligand protection methods,which exhibit unique properties such as suppressing structure-sensitive side reactions.However,this method is limited by the use of different metal precursor salts corresponding to different ligands.An alternative approach,the ion exchange(IE)method,can overcome this limitation to some extent.Nevertheless,there is still an urgent need to address the stabilization of metals(especially precious metals)by using IE method.Here,we reported a Pt cluster catalyst prepared mainly by anchoring Pt atoms via O located near the framework Zn in zincosilicate zeolites and riveted by zeolite surface rings after reduction(reduced Pt/Zn-3-IE).The catalyst can achieve an initial propane conversion of 26%in a pure propane atmosphere at 550℃and shows little deactivation even after 7.5 d of operation.Moreover,the alteration of catalyst by the introduction of framework Zn was also highlighted and interpreted.展开更多
Propane dehydrogenation(PDH)is a vital industrial process for producing propene,utilizing primarily Cr-based or Pt-based catalysts.These catalysts often suffer from challenges such as the toxicity of Cr,the high costs...Propane dehydrogenation(PDH)is a vital industrial process for producing propene,utilizing primarily Cr-based or Pt-based catalysts.These catalysts often suffer from challenges such as the toxicity of Cr,the high costs of noble metals like Pt,and deactivation issues due to sintering or coke formation at elevated temperatures.We introduce an exceptional Ru-based catalyst,Ru nanoparticles anchored on a nitrogendoped carbon matrix(Ru@NC),which achieves a propane conversion rate of 32.2%and a propene selectivity of 93.1%at 550°C,with minimal coke deposition and a low deactivation rate of 0.0065 h^(-1).Characterizations using techniques like TEM and XPS,along with carefully-designed controlled experiments,reveal that the notable performance of Ru@NC stems from the modified electronic state of Ru by nitrogen dopant and the microporous nature of the matrix,positioning it as a top contender among state-of-the-art PDH catalysts.展开更多
Transition metal cobalt exhibits strong activation capabilities for alkanes,however,the instability of Co sites leads to sintering and coke deposition,resulting in rapid deactivation.Hierarchical zeolites,with their d...Transition metal cobalt exhibits strong activation capabilities for alkanes,however,the instability of Co sites leads to sintering and coke deposition,resulting in rapid deactivation.Hierarchical zeolites,with their diverse pore structures and high surface areas,are used to effectively anchor metals and enhance coke tolerance.Herein,a post-treatment method using an alkaline solution was employed to synthesize meso-microporous zeolite supports,which were subsequently loaded with Co species for propane dehydrogenation catalyst.The results indicate that the application of NaOH,an inorganic base,produces supports with a larger mesopore volume and more abundant hydroxyl nests compared to TPAOH,an organic base.UV-vis,Raman,and XPS analyses reveal that Co in the 0.5Co/SN-1-0.05 catalyst is mainly in the form of tetrahedral Co^(2+),which effectively activates C-H bonds.In contrast,the 0.5Co/S-1 catalyst contains mainly Co_(3)O_(4)species.Co^(2+)supported on hierarchical zeolites shows better propane conversion(58.6%)and propylene selectivity(>96%)compared to pure silica zeolites.Coke characterization indicates that hierarchical zeolites accumulate more coke,but it is mostly in the form of easily removable disordered carbon.The mesopores in the microporous zeolite support help disperse the active Co metal and facilitate coke removal during dehydrogenation,effectively preventing deactivation from sintering and coke coverage.展开更多
Metal oxide catalysts are widely employed in propane dehydrogenation(PDH)for propylene synthesis,requiring sequential reduction-reaction-regeneration cycles.However,the eff ect of water present in the inlet gas or rea...Metal oxide catalysts are widely employed in propane dehydrogenation(PDH)for propylene synthesis,requiring sequential reduction-reaction-regeneration cycles.However,the eff ect of water present in the inlet gas or reactor on the catalytic per-formance of various metal oxides remains insuffi ciently understood.This study examines the infl uence of water on supported metal oxide catalysts,specifi cally CoO x/Al_(2)O_(3),VO x/Al_(2)O_(3),and an industrial analog CrO x/Al_(2)O_(3) catalyst.By combining titration experiments,in situ Fourier transform infrared spectroscopy,kinetic analysis,and isotopic techniques,we demon-strate that even trace amounts of water can markedly suppress PDH performance via dissociative adsorption on the oxide surface.Methanol pretreatment eff ectively scavenges adsorbed water,recovering Lewis acid-base sites and consequently restoring PDH activity.This work underscores the profound inhibitory role of trace water in PDH over metal oxide catalysts and illustrates the potential of methanol pretreatment as an effective strategy to mitigate this limitation.展开更多
Propane dehydrogenation(PDH)is a key process for increasing the production of propylene,which is an important part of the chemical industry.Platinum-based catalysts have emerged as efficient catalysts for this reactio...Propane dehydrogenation(PDH)is a key process for increasing the production of propylene,which is an important part of the chemical industry.Platinum-based catalysts have emerged as efficient catalysts for this reaction due to their excellent activity and selectivity.However,challenges such as high platinum cost,catalyst deactivation,and side reactions remain significant barriers to their widespread use in industry.This review provides a comprehensive overview of recent advances in platinumbased catalysts for PDH,focusing on strategies to optimize their performance.We discuss the design and synthesis of Pt-based catalysts,emphasizing the role of promoters,such as Sn,Zn,Ga,and other promoters,in improving selectivity and stability.We also explore the effects of support materials and zeolite encapsulated catalysts on dispersion and activity for Pt-based catalysts.In addition,we highlight the use of machine learning to predict catalyst performance and guide the development of nextgeneration Pt-based catalyst materials.This review synthesizes insights from experimental studies and machine learning computational modeling and aims to provide a route for overcoming the limitations of Pt-based catalysts and advancing the PDH process.展开更多
Direct propane dehydrogenation(DPDH)represents a highly attractive route for on-purpose propylene production,a key building block in the petrochemical industry.In particular,among various catalytic platforms,vanadium-...Direct propane dehydrogenation(DPDH)represents a highly attractive route for on-purpose propylene production,a key building block in the petrochemical industry.In particular,among various catalytic platforms,vanadium-based catalysts have emerged as promising candidates due to their tunable properties including redox ability,surface acidity,and resistance to coking.Although the catalytic community has obtained great achievement in this area,how to promote vanadium-based catalysts towards the next step in DPDH applications like industrial-level implementations is still challenging.Moreover,there are still several controversial theories in our community,meaning it is necessary to clarify these indistinct points to pave the way for the next generation of research.Herein,the pivotal modification strategies of vanadium-based catalysts have been summarized via introducing representative works.In addition,the current unclear mechanism and research gaps,especially in the issues of deactivation and selectivity control,are also revealed so that the potential research directions are well-founded proposed.By integrating fundamental understanding and practical considerations,this review aims to inspire the further development of vanadium-based DPDH catalysts for in-depth academic research and next-generation industrial deployment.展开更多
Mesoporous Ni-Al composite oxide(MNA)with excellent textural and surface properties was prepared using a facile calcination-induced metal heteroatom doping approach and was evaluated as support of Pt-based catalyst fo...Mesoporous Ni-Al composite oxide(MNA)with excellent textural and surface properties was prepared using a facile calcination-induced metal heteroatom doping approach and was evaluated as support of Pt-based catalyst for methylcyclohexane dehydrogenation at a low temperature.The homogeneous incorporation of Ni atoms into the mesoporous framework of alumina and the formation of surface Ni-O-Al bonds benefit the generation of surface coordinated unsaturated aluminum species,which play a crucial role in highly homogenously dispersing Pt active sites in a form of single-atom clusters.Consequently,the resultant catalyst Pt/MNA displayed significantly improved catalytic performance.For example,at 300℃,catalyst Pt/MNA demonstrated a notable catalytic activity with a maximum hydrogen evolution rate of 3057 mmol/gPt/min,even after a long-time reaction up to 100 h or regeneration,which is inspiringly superior to the state-of-the-art supported Ptbased catalysts.The obviously boosted catalytic reactivity of catalyst Pt/MNA can be attributed to the excellent structural and textural properties,the remarkably raised Pt utilization efficiency,and the synergic catalytic effect derived from the interface electron transfer from support MNA to metallic Pt active sites.Our results provided a rational design strategy for the development of promising Pt-based catalyst for methylcyclohexane dehydrogenation,which is vital in the utilization of methylcyclohexane-toluene system for hydrogen storage.展开更多
Magnesium-based hydrogen storage materials are promising candidates for hydrogen storage due to their high storage density and environmentally friendly properties.However,the high dehydrogenation enthalpy change(appro...Magnesium-based hydrogen storage materials are promising candidates for hydrogen storage due to their high storage density and environmentally friendly properties.However,the high dehydrogenation enthalpy change(approximately 75 kJ/mol H_(2))and high dehydrogenation temperature(573 K at 0.1 MPa)of MgH_(2),limits the engineering application of Mg/MgH_(2) as a hydrogen storage material.This work reviews the prediction models and methods of enthalpy changes for hydriding/dehydriding(H/D)reactions in order to find out the ideas and ways to reduce them.The mechanism behind the improvement methods mainly includes two aspects,weakening Mg-H bond and compensating heat of reaction.Proceed from this,the experimental methods and enthalpy data as well as calculated values of enthalpy changes were compared systematically.Elements such as Ti,Nb,V,etc.,with a small electronegativity difference compared to Mg,can reduce the hydrogenation and dehydrogenation enthalpy changes by forming strong Metal-H or Metal-Mg bonds.In addition,this review concludes with an outlook on the remaining challenge issues and prospects.展开更多
The selective activation of C-H bonds is pivotal in catalysis for converting hydrocarbons into value-added chemicals.Ethylbenzene dehydrogenation to styrene is crucial process to produce polystyrene and its derivative...The selective activation of C-H bonds is pivotal in catalysis for converting hydrocarbons into value-added chemicals.Ethylbenzene dehydrogenation to styrene is crucial process to produce polystyrene and its derivatives used in synthetic materials.Herein,K-Cr@Y with zeolite-encaged isolated O=Cr(VI)=O species modified by extraframework potassium ions is constructed,showing remarkable performance in CO_(2)-promoted ethylbenzene dehydrogenation with initial ethylbenzene conversion of 66%and styrene selectivity of 96%,outperforming other M-Cr@Y catalysts(M=Li,Na,Rb,Cs).Extraframework potassium ions can modulate the electron density of zeolite-encaged Cr(VI)species and therefore facilitate C–H bond activation in ethylbenzene molecules.The gradual reduction of zeolite-encaged O=Cr(VI)=O to less active Cr(IV)=O species by dihydrogen during ethylbenzene dehydrogenation is evidenced by comprehensive characterization results,and Cr(IV)=O can be re-oxidized to O=Cr(VI)=O species upon simple calcination regeneration.The results from in situ DRIFT spectroscopy elucidate the critical promotion role of CO_(2)in ethylbenzene dehydrogenation over K-Cr@Y by retarding the over-reduction of zeolite-encaged Cr species to inactive Cr(III)species and suppressing coke deposition.This study advances the rational design of non-noble metal catalysts for CO_(2)-promoted ethylbenzene dehydrogenation with zeolite-encaged high valence transition metal ions modulated by extraframework cations.展开更多
基金supported by National Natural Science Foundation of China(22478076,U25B6005)National Key R&D Program of China(2021YFA1500302)+1 种基金Industrial Joint Fund of Qingyuan Innovation Laboratory(00422001)111 Project(D17005).
文摘The efficient storage and release of H_(2)are pivotal for the advancement of hydrogen energy technologies.Cyclohexane,as a promising liquid organic hydrogen carrier(LOHC),provides a safe and practical solution for H_(2)storage.However,the performance limitations of dehydrogenation catalysts have hindered the rapid development of LOHC technology.In this study,we successfully developed boron-modified Pt/ZrO_(2)catalysts,which exhibit exceptional catalytic performance in cyclohexane dehydrogenation.The optimal boron content is determined to be 0.5 wt.%,with the Pt/0.5B–ZrO_(2)catalyst achieving high turnover frequency(TOF)of 10,627.3 mol_(H_(2))·mol_(Pt)^(−1)·h^(−1)and benzene selectivity of 99%at 295°C.The catalyst also demonstrates H_(2)evolution rate of 908 mmol·g_(Pt)^(−1)·min^(−1)and low deactivation rate of 0.0043 h^(−1).Remarkably,the catalyst displays outstanding stability and regeneration performance,maintaining its activity without significant loss during a 60-h dehydrogenation reaction and retaining a cyclohexane conversion of 77.2%after 10 consecutive cycles.Comprehensive characterization techniques,including XPS,CO-FTIR,NH_(3)-TPD,H_(2)-TPD,Benzene-TPD,and Py-IR,reveals that boron modification reduces the electron density of Pt,generating abundant electron-deficient Pt atoms.These electron-deficient Pt atoms enhance H_(2)adsorption and accelerate benzene desorption,effectively preventing coke formation from deep benzene dehydrogenation,which is responsible for the high catalytic performance of the Pt/0.5B–ZrO_(2)catalyst.These findings offer a valuable strategy for optimizing dehydrogenation catalysts in LOHC technologies,addressing a critical bottleneck in the development of this essential energy storage solution.
文摘Propylene,a pivotal chemical feedstock,is extensively used in synthesizing high-value derivatives such as polypropylene and acrylonitrile[1].Although propylene is predominantly produced via naphtha cracking,a persistent supply-demand gap exists[2].Non-oil routes,such as propane dehydrogenation(PDH),are increasingly attractive,particularly with the availability of shale gas[3].Modern non-oxidative PDH heavily relies on Pt nanoparticle catalysts promoted with SnOx(e.g.,PtSn/Al2O3 used in Honeywell UOP's Oleflex process)[4].However,these systems suffer from inherent limitations:high Pt costs,coke formation via deep dehydrogenation,and sintering during regeneration-necessitating environmentally detrimental oxychlorination treatments to restore activity[5].
基金supported by the National Key R&D Program of China(Grant No.2022YFA1506000)Gusu Innovation and Entrepreneurship Leading Talents Program(ZXL2022497)+5 种基金Jiangsu Distinguished Professor programfinancial support by National Natural Science Foundation of China(Grant No.22301057)Natural Science Foundation of Hebei Province(Grant No.B2023201065)Science Research Project of Hebei Education Department(Grant No.BJK2024103)supported by the Open Research Fund of Shanghai Key Laboratory of High-resolution Electron MicroscopyOpen Project of State Key Laboratory of Supramolecular Structure and Materials(sklssm2024019),ShanghaiTech University。
文摘The dehydrogenation of alkanes has emerged as a vital complementary process to address the increasing global demand for olefins.A key challenge remains in the construction of novel active centers that offer superior activity,stability,and cost-effectiveness.Herein,tricoordinated cobalt atoms were successfully fabricated through an in-situ ligand-protected synthesis by introducing tungsten atoms into zeolite frameworks.These unsaturated Co species efficiently activate C-H bonds while suppressing C-C bond cleavage,resulting in exceptional catalytic activity and olefin selectivity in both propane and ethane dehydrogenation reactions.The optimized Co_(0.2%)@0.01W-S-1 catalyst demonstrated an impressive propylene formation rate of 15.2 molC_(3H6)gcC h^(-1)at 823 K and an ethylene formation rate of 240.3mol_(C2H4)g_(Co)^(-1)h^(-1)at 913 K,with propylene and ethylene selectivities of 99.0%and 97.5%,respectively.These results not only significantly surpass conventional tetracoordinated Co catalysts but also rival some Pt-based catalysts under similar conditions.Importantly,the catalyst exhibited excellent stability in dehydrogenation reactions,with no significant loss in catalytic activity after five consecutive regeneration cycles.This work offers valuable insights into the design of zeolite-supported non-precious metal catalysts with high activity and durability for efficient alkane dehydrogenation.
基金Yijing Wang acknowledges the funding support of the National Key Research and Development Program of China(No.2021YFB4000604)the National Natural Science Foundation of China(No.52271220)+6 种基金the Higher Education Discipline Innovation Project(No.B12015)“the Fundamental Research Funds for the Central Universities”Huaiyu Shao acknowledges the funding support of the Multi-Year Research Grant(MYRG)from the University of Macao(No.MYRG2022-00105-IAPME)the Joint Scientific Research Project Funding by the National Natural Science Foundation of China and the Macao Science and Technology Development Fund(No.0090/2022/AFJ)the Macao Science and Technology Development Fund(FDCT)for funding No.006/2022/ALC of the Macao Centre for Research and Development in Advanced Materials(No.2022-2024)the Natural Science Foundation of Guangdong Province(Grant No.2023A1515010765)the Shenzhen-Hong Kong-Macao Science and Technology Innovation Project(Category C).
文摘Herein,we report the multi-metal atomic catalysts for solid-state dehydrogenation of MgH_(2).It aims to reveal the multi-element synergy in catalysts for solid-state hydrogen storage.The kinetic measurements and fitting reveal two mechanisms:one shows a maximum rate at the early stage,such as V and Cr;the other needs a temperature-sensitive preparation time for its maximum rate,such as Ni.The combina-tion of two catalyst components demonstrates the best kinetics:V and Cr boost the initial dehydrogena-tion,and Ni benefits the further hydrogen transfer which alleviates the rate of decay.This work provides guidelines for the design of multi-element doped catalysts for MgH_(2) dehydrogenation.
文摘Non-oxidative dehydrogenation of propane(PDH)is an important route for large-scale on purpose propene production.Although cobalt-based catalysts are promising alternatives to currently used platinum-or chromium oxide-based catalysts,their further developments are hindered by the uncertainties related to the kind of the active sites involved in the desired and side reactions.To contribute to closing such a gap,we systematically investigate the role of oxidized CoO_(x) and metallic Co0 species in the PDH reaction over catalysts based in Silicalite-1 with supported CoO_(x) species differing in their redox properties.C_(3)H_(8) pulse experiments with sub-millisecond and second resolution at pulse sizes of about 13 and 2200 nmol,respectively,combined with in-depth catalyst characterization and PDH tests at different propane conversions enabled us to understand how the reaction-induced reduction of CoO_(x) affects product selectivity.Propane readily reacts with CoO_(x) to yield propene,carbon oxides and water.The formed Co0 species show high activity to coking and cracking reactions.However,if the size of such species is below 2 nm,these undesired reactions are significantly hindered due to the coverage of the active sites by carbon-containing species.The remaining uncovered surface Co0 sites selectively dehydrogenate propane to propene.The best-performing catalyst showed higher activity than a commercial-like K-CrOx/Al_(2)O_(3) and operated durable in a series of 10 dehydrogenation/regeneration cycles under industrial relevant conditions.The space time yield of propene formation of 0.97 kg·h^(-1)·kgcat^(-1) was achieved at 550℃,52%equilibrium propane conversion and 95% propene selectivity.
文摘Modifying the electronic density of states and the synergistic effect of the active centers by introducing a second metal present an efficient strategy to tune physi/chemi-sorption,probably lead to improving catalytic performances.Herein,bimetallic Ni_(3)Mo/Al_(2)O_(3)catalyst was demonstrated and exhibited over 5 times more active than Pt/Al_(2)O_(3)toward the ethane dehydrogenation(EDH)as well as 2-10 times activity enhancement compared with their monometallic Ni and Mo counterparts and other Ni-based bimetallic nanoparticles.Kinetic studies revealed that the activation energy over Ni_(3)Mo/Al_(2)O_(3)(111 kJ mol^(-1))was much lower than that of Ni(157 kJ mol^(-1))and Mo(171 kJ·mol^(-1)).DFT calculations showed ethane was adsorbed on the Ni or Mo surface in a more parallel configuration,whereas over Ni_(3)Mo it adopted an inclined configuration.This change promoted ethane adsorption and pre-activation of the C-H bond,thereby benefiting the ethane dehydrogenation process on the Ni_(3)Mo surface.
文摘Propane dehydrogenation(PDH)has emerged as a key on-purpose technology for the production of propylene,but it often depends on toxic chromium and expensive platinum catalysts,highlighting the need for environmentally friendly and cost-effective alternatives.In this study,we developed a facile impregnation method to fabricate unsaturated Co single-atoms with a tricoordinated Co_(1)O_(3)H_(x) structure by regulating silanol nests in purely siliceous Beta zeolites.Detailed PDH catalytic tests and characterizations revealed a positive correlation between the presence of silanol nests and enhanced catalytic activity.Additionally,the unsaturated Co single-atoms exhibited a carbon deposition rate more than an order of magnitude slower than that of Co nanoparticles.Notably,the optimized Co_(0.3%)/deAl-meso-Beta catalyst achieved a record-high propylene formation rate of 21.2 mmol_(C3H6) g_(cat)^(-1) h^(-1),with an exceptional propylene selectivity of 99.1%at 550℃.Moreover,the Co_(0.3%)/deAl-meso-Beta catalyst demonstrated excellent stability,with negligible deactivation after 5 consecutive regeneration cycles.This study emphasizes the pivotal role of silanol nests of zeolites in stabilizing and modulating the coordination environment of metallic active sites,providing valuable insights for the design of high-activity,high-stability,and low-cost PDH catalysts.
基金financially supported by the National Natural Science Foundation of China(Nos.52272190 and 22178023)the National Key R&D Program of China(No.2021YFB4001401)。
文摘In response to the increasing demand of ethylene,electrochemical ethane nonoxidative dehydrogenation(EENDH)to ethylene by protonic ceramic electrolysis cells(PCECs)is developed.However,existing anode materials exhibit poor proton conductivity and limited catalytic activity.Herein,a novel Sr_(1.95)Fe_(1.4)Co_(0.1)Mo_(0.4)Zr_(0.1)O_(6-δ)(SFCMZ)anode is prepared as PCECs anode for EENDH.Zr doping increases the oxygen vacancies and enhances the proton conductivity of SFCMZ.Moreover,an alloy-oxide heterostructure(Co Fe@SFCMZ)is formed through in-situ exsolution of Co Fe alloy nanoparticles under reduction conditions,generating abundant oxygen vacancies and improving its catalytic activity.Co Fe@SFCMZ cell achieves an electrolysis current density of 0.87 A/cm^(2) at 700℃ under 1.6 V,with an ethane conversion rate of 34.22%and corresponding ethylene selectivity of 93.4%.These results demonstrate that Co Fe@SFCMZ anode exhibits excellent electrocatalytic activity,suggesting promising applications for EENDH.
基金support from Zhejiang Provincial Natural Science Foundation of China(LZ23B060001).
文摘Supported metal oxide catalysts have garnered significantattention in oxidative dehydrogenation(ODH)due to their tunable metal-support interactions.The pentacoordinate Al^(3+)(Al_(V)^(3+))in γ-Al_(2)O_(3)supports plays a pivotal role in modulating metal-support interaction.This study investigates oxalic acid(OA)pretreatment as a defect engineering strategy to enhance the catalytic performance of CeO_(2)/γ-Al_(2)O_(3)in cyclohexane ODH.Through integrated characterization(XRD,27Al MAS NMR,H_(2)-TPR,TPRO,MS,XPS)and catalytic testing,we demonstrate that optimal OA treatment(1:10 ratio)eliminates 100%of surface Al_(V)^(3+)defects while enhancing CeO_(2)crystallinity and interfacial oxygen mobility.The removal of Al_(V)^(3+)species restructures metal-support interaction,accelerating interfacial oxygen mobility.In oxidation dehydrogenation of cyclohexane,the modified CeO_(2)/γ-Al_(2)O_(3)achieves 29%of cyclohexane conversion with stable selectivity of 49%cyclohexene.These findingsprovide an initial framework for designing redox-active catalysts via targeted support modificationin CeO_(2)/γ-Al_(2)O_(3)systems,emphasizing the relationship between metal-support interaction and oxygen mobility.
文摘Recent studies have revealed the extraordinary performance of zirconium oxide in propane dehydrogenation,which is attributed to the excellent reactivity of the coordinatively unsaturated zirconium sites(Zr_(cus))around the oxygen vacancies.The origin of the enhanced catalytic activity of ZrO_(2)with defective tetrahedral Zr sites was examined by direct comparison with its pristine counterpart in the current study.Electronic-structure analysis revealed that electrons from oxygen removal were localized within vacancies on the defective surface,which directly attacked the C-H bond in propane.The involvement of localized electrons activates the C-H bond via back-donation to the antibonding orbital on the defective surface;conversely,charge is transferred from propane to the pristine surfaces.The barrier for the first C-H bond activation is clearly significantly reduced on the defective surfaces compared to that on the pristine surfaces,which verifies the superior activity of Zr_(cus).Notably,however,the desorption of both propene and hydrogen molecules from Zr_(cus)is more difficult due to strong binding.The calculated turnover frequency(TOF)for propene formation demonstrates that the pristine surfaces exhibit better catalytic performance at lower temperatures,whereas the defective surfaces have a larger TOF at high temperatures.However,the rate-determining step and reaction order on the defective surface differ from those on the pristine surface,which corroborates that the catalysts follow different mechanisms.A further optimization strategy was proposed to address the remaining bottlenecks in propane dehydrogenation on zirconium oxide.
基金supported by the National Key Research and Development Program of China(2022YFE0208300)the Natural Science Foundation of China(22078354)。
文摘The oxidative dehydrogenation of propane to propylene using CO_(2)(CO_(2)-ODH)offers a promising route for both propylene production and CO_(2)utilization.In this study,we investigate the effect of alkali metal doping on Pt-based catalysts in CO_(2)-ODH reactions.The optimized 0.1 KPt/S-1 catalyst achieved a high propane conversion of 48.3%,propylene selectivity of 85.5%,and CO_(2)conversion of 19.1%at a low temperature of 500℃with the Pt loading of 0.2 wt%and K loading of 0.1 wt%respectively.Characterization techniques,including high-resolution transmission electron microscope(HR-TEM),CO-diffuse reflectance infrared Fourier transform spectroscopy(CO-DRIFTS),X-ray absorption fine structure(XAFS),and X-ray Photoelectron Spectroscopy(XPS),revealed that the doping of K with Pt led to a strong interaction between potassium and platinum(Pt-KO_(x)cluster).This interaction resulted in a reduction of Pt particle size and a local enrichment of electron density around Pt atoms.These structural modifications improved the anchoring of Pt nanoparticles and enhanced Pt atom dispersion,thereby enhancing the activity of the catalyst and minimizing side reactions.Additionally,pyridine infrared(Py-IR)and temperature-programmed desorption(TPD)studies demonstrated that the prepared0.1 KPt/S-1 catalyst exhibited optimal acidity,which promoted C–H activation and facilitated the efficient adsorption and activation of CO_(2).These dual effects significantly lowered the activation energy for CO_(2)-ODH,enabling efficient dehydrogenation to propylene at a lower temperature of 500℃.This work highlights the critical role of alkali metal doping in modifying the electronic properties of Pt and optimizing catalyst acidity,which collectively contribute to the enhanced performance of the 0.1 KPt/S-1 catalyst.These findings offer valuable insights into the mechanistic pathway of CO_(2)-ODH and provide a foundation for the rational design of high-performance dehydrogenation catalysts.
文摘Dispersing metals from nanoparticles to clusters is often achieved using ligand protection methods,which exhibit unique properties such as suppressing structure-sensitive side reactions.However,this method is limited by the use of different metal precursor salts corresponding to different ligands.An alternative approach,the ion exchange(IE)method,can overcome this limitation to some extent.Nevertheless,there is still an urgent need to address the stabilization of metals(especially precious metals)by using IE method.Here,we reported a Pt cluster catalyst prepared mainly by anchoring Pt atoms via O located near the framework Zn in zincosilicate zeolites and riveted by zeolite surface rings after reduction(reduced Pt/Zn-3-IE).The catalyst can achieve an initial propane conversion of 26%in a pure propane atmosphere at 550℃and shows little deactivation even after 7.5 d of operation.Moreover,the alteration of catalyst by the introduction of framework Zn was also highlighted and interpreted.
基金supported by the National Key Research and Development Project of China(No.2022YFE0113800)the National Natural Science Foundation of China(No.22102013)+2 种基金Natural Science Foundation of Chongqing(No.cstc2021jcyj-msxmX0945)Venture and Innovation Support Program for Chongqing Overseas Returnees(No.cx2020107)Thousand Talents Program for Distinguished Young Scholars,Postdoctoral Fellowship Program of CPSF(No.GZB20230910)。
文摘Propane dehydrogenation(PDH)is a vital industrial process for producing propene,utilizing primarily Cr-based or Pt-based catalysts.These catalysts often suffer from challenges such as the toxicity of Cr,the high costs of noble metals like Pt,and deactivation issues due to sintering or coke formation at elevated temperatures.We introduce an exceptional Ru-based catalyst,Ru nanoparticles anchored on a nitrogendoped carbon matrix(Ru@NC),which achieves a propane conversion rate of 32.2%and a propene selectivity of 93.1%at 550°C,with minimal coke deposition and a low deactivation rate of 0.0065 h^(-1).Characterizations using techniques like TEM and XPS,along with carefully-designed controlled experiments,reveal that the notable performance of Ru@NC stems from the modified electronic state of Ru by nitrogen dopant and the microporous nature of the matrix,positioning it as a top contender among state-of-the-art PDH catalysts.
基金supported by the National Natural Science Foundation of China(Nos.22035009,22178381)the National Key R&D Program of China(Nos.2021YFA1501301,2021YFC2901100)the State Key Laboratory of Heavy Oil Processing(No.2021-03).
文摘Transition metal cobalt exhibits strong activation capabilities for alkanes,however,the instability of Co sites leads to sintering and coke deposition,resulting in rapid deactivation.Hierarchical zeolites,with their diverse pore structures and high surface areas,are used to effectively anchor metals and enhance coke tolerance.Herein,a post-treatment method using an alkaline solution was employed to synthesize meso-microporous zeolite supports,which were subsequently loaded with Co species for propane dehydrogenation catalyst.The results indicate that the application of NaOH,an inorganic base,produces supports with a larger mesopore volume and more abundant hydroxyl nests compared to TPAOH,an organic base.UV-vis,Raman,and XPS analyses reveal that Co in the 0.5Co/SN-1-0.05 catalyst is mainly in the form of tetrahedral Co^(2+),which effectively activates C-H bonds.In contrast,the 0.5Co/S-1 catalyst contains mainly Co_(3)O_(4)species.Co^(2+)supported on hierarchical zeolites shows better propane conversion(58.6%)and propylene selectivity(>96%)compared to pure silica zeolites.Coke characterization indicates that hierarchical zeolites accumulate more coke,but it is mostly in the form of easily removable disordered carbon.The mesopores in the microporous zeolite support help disperse the active Co metal and facilitate coke removal during dehydrogenation,effectively preventing deactivation from sintering and coke coverage.
基金supported by the National Key R&D Program of China(No.2023YFA1507800)the National Science Foundation of China(Nos.22121004,22122808,22478279,and 22108201)+1 种基金the Haihe Laboratory of Sustainable Chemical Trans-formations,the Program of Introducing Talents of Discipline to Uni-versities(No.BP0618007)the XPLORER PRIZE.
文摘Metal oxide catalysts are widely employed in propane dehydrogenation(PDH)for propylene synthesis,requiring sequential reduction-reaction-regeneration cycles.However,the eff ect of water present in the inlet gas or reactor on the catalytic per-formance of various metal oxides remains insuffi ciently understood.This study examines the infl uence of water on supported metal oxide catalysts,specifi cally CoO x/Al_(2)O_(3),VO x/Al_(2)O_(3),and an industrial analog CrO x/Al_(2)O_(3) catalyst.By combining titration experiments,in situ Fourier transform infrared spectroscopy,kinetic analysis,and isotopic techniques,we demon-strate that even trace amounts of water can markedly suppress PDH performance via dissociative adsorption on the oxide surface.Methanol pretreatment eff ectively scavenges adsorbed water,recovering Lewis acid-base sites and consequently restoring PDH activity.This work underscores the profound inhibitory role of trace water in PDH over metal oxide catalysts and illustrates the potential of methanol pretreatment as an effective strategy to mitigate this limitation.
文摘Propane dehydrogenation(PDH)is a key process for increasing the production of propylene,which is an important part of the chemical industry.Platinum-based catalysts have emerged as efficient catalysts for this reaction due to their excellent activity and selectivity.However,challenges such as high platinum cost,catalyst deactivation,and side reactions remain significant barriers to their widespread use in industry.This review provides a comprehensive overview of recent advances in platinumbased catalysts for PDH,focusing on strategies to optimize their performance.We discuss the design and synthesis of Pt-based catalysts,emphasizing the role of promoters,such as Sn,Zn,Ga,and other promoters,in improving selectivity and stability.We also explore the effects of support materials and zeolite encapsulated catalysts on dispersion and activity for Pt-based catalysts.In addition,we highlight the use of machine learning to predict catalyst performance and guide the development of nextgeneration Pt-based catalyst materials.This review synthesizes insights from experimental studies and machine learning computational modeling and aims to provide a route for overcoming the limitations of Pt-based catalysts and advancing the PDH process.
基金support from Liaoning Revitalization Talents Program(XLYC2203068)National Natural Science Foundation of China(21902116)2024 Fundamental Research Funding of the Educational Department of Liaoning Province.Y.L.acknowledges the Program of China Scholarships Council(No.202206250016).
文摘Direct propane dehydrogenation(DPDH)represents a highly attractive route for on-purpose propylene production,a key building block in the petrochemical industry.In particular,among various catalytic platforms,vanadium-based catalysts have emerged as promising candidates due to their tunable properties including redox ability,surface acidity,and resistance to coking.Although the catalytic community has obtained great achievement in this area,how to promote vanadium-based catalysts towards the next step in DPDH applications like industrial-level implementations is still challenging.Moreover,there are still several controversial theories in our community,meaning it is necessary to clarify these indistinct points to pave the way for the next generation of research.Herein,the pivotal modification strategies of vanadium-based catalysts have been summarized via introducing representative works.In addition,the current unclear mechanism and research gaps,especially in the issues of deactivation and selectivity control,are also revealed so that the potential research directions are well-founded proposed.By integrating fundamental understanding and practical considerations,this review aims to inspire the further development of vanadium-based DPDH catalysts for in-depth academic research and next-generation industrial deployment.
基金supported by the National Natural Science Foundation of China(21975174 and 22378286)the Natural Science Foundation of Shanxi Province,China(202403021221036)+1 种基金the Funds for Central Government to Guide Local Science and Technology Development(YDZJSX2021A014)the Research Project Supported by Shanxi Scholarship Council of China(2024-036).
文摘Mesoporous Ni-Al composite oxide(MNA)with excellent textural and surface properties was prepared using a facile calcination-induced metal heteroatom doping approach and was evaluated as support of Pt-based catalyst for methylcyclohexane dehydrogenation at a low temperature.The homogeneous incorporation of Ni atoms into the mesoporous framework of alumina and the formation of surface Ni-O-Al bonds benefit the generation of surface coordinated unsaturated aluminum species,which play a crucial role in highly homogenously dispersing Pt active sites in a form of single-atom clusters.Consequently,the resultant catalyst Pt/MNA displayed significantly improved catalytic performance.For example,at 300℃,catalyst Pt/MNA demonstrated a notable catalytic activity with a maximum hydrogen evolution rate of 3057 mmol/gPt/min,even after a long-time reaction up to 100 h or regeneration,which is inspiringly superior to the state-of-the-art supported Ptbased catalysts.The obviously boosted catalytic reactivity of catalyst Pt/MNA can be attributed to the excellent structural and textural properties,the remarkably raised Pt utilization efficiency,and the synergic catalytic effect derived from the interface electron transfer from support MNA to metallic Pt active sites.Our results provided a rational design strategy for the development of promising Pt-based catalyst for methylcyclohexane dehydrogenation,which is vital in the utilization of methylcyclohexane-toluene system for hydrogen storage.
基金financially supported by the National Key Research and Development Program of China(No.2023YFB3809101)the National Natural Science Foundation of China(No.U23A20128)the Chongqing Science and Technology Commission of China(CSTC2024YCJHBGZXM0041).
文摘Magnesium-based hydrogen storage materials are promising candidates for hydrogen storage due to their high storage density and environmentally friendly properties.However,the high dehydrogenation enthalpy change(approximately 75 kJ/mol H_(2))and high dehydrogenation temperature(573 K at 0.1 MPa)of MgH_(2),limits the engineering application of Mg/MgH_(2) as a hydrogen storage material.This work reviews the prediction models and methods of enthalpy changes for hydriding/dehydriding(H/D)reactions in order to find out the ideas and ways to reduce them.The mechanism behind the improvement methods mainly includes two aspects,weakening Mg-H bond and compensating heat of reaction.Proceed from this,the experimental methods and enthalpy data as well as calculated values of enthalpy changes were compared systematically.Elements such as Ti,Nb,V,etc.,with a small electronegativity difference compared to Mg,can reduce the hydrogenation and dehydrogenation enthalpy changes by forming strong Metal-H or Metal-Mg bonds.In addition,this review concludes with an outlook on the remaining challenge issues and prospects.
文摘The selective activation of C-H bonds is pivotal in catalysis for converting hydrocarbons into value-added chemicals.Ethylbenzene dehydrogenation to styrene is crucial process to produce polystyrene and its derivatives used in synthetic materials.Herein,K-Cr@Y with zeolite-encaged isolated O=Cr(VI)=O species modified by extraframework potassium ions is constructed,showing remarkable performance in CO_(2)-promoted ethylbenzene dehydrogenation with initial ethylbenzene conversion of 66%and styrene selectivity of 96%,outperforming other M-Cr@Y catalysts(M=Li,Na,Rb,Cs).Extraframework potassium ions can modulate the electron density of zeolite-encaged Cr(VI)species and therefore facilitate C–H bond activation in ethylbenzene molecules.The gradual reduction of zeolite-encaged O=Cr(VI)=O to less active Cr(IV)=O species by dihydrogen during ethylbenzene dehydrogenation is evidenced by comprehensive characterization results,and Cr(IV)=O can be re-oxidized to O=Cr(VI)=O species upon simple calcination regeneration.The results from in situ DRIFT spectroscopy elucidate the critical promotion role of CO_(2)in ethylbenzene dehydrogenation over K-Cr@Y by retarding the over-reduction of zeolite-encaged Cr species to inactive Cr(III)species and suppressing coke deposition.This study advances the rational design of non-noble metal catalysts for CO_(2)-promoted ethylbenzene dehydrogenation with zeolite-encaged high valence transition metal ions modulated by extraframework cations.
