The development of robust and active oxygen evolution reaction(OER)electrocatalysts is urgently desirable for the widespread implementation of proton exchange membrane water electrolyzers(PEMWE),yet remains a critical...The development of robust and active oxygen evolution reaction(OER)electrocatalysts is urgently desirable for the widespread implementation of proton exchange membrane water electrolyzers(PEMWE),yet remains a critical challenge.We propose a catalyst named U-IrRuO_(x)@IrRu(where“U”denotes“ultrathin”),which features a spontaneously formed amorphous oxide shell that synergistically optimizes the electronic structure and corrosion resistance.Combined experimental and theoretical studies reveal that the oxyphilic Ru-induced electronic modulation weakens Ir-O binding strength,thereby accelerating the rate-determining step of ^(*)OOH formation.In addition,the metallic alloy core functions as an electron reservoir,suppressing excessive oxidation of active sites while ensuring high conductivity.Due to these attributes,the U-IrRuO_(x)@IrRu demonstrates a low overpotential of 230 mV at 10 mA cm^(-2),outperforming commercial IrO_(2)(CM)by 65 mV.When integrated into a PEMWE with an ultra-low Ir loading of 0.25 mg_(Ir)cm^(-2),it delivers an industrial current density of 2 A cm^(-2)at 1.74 V and 3 A cm^(-2)at 1.836 V,surpassing the U.S.Department of Energy(DOE)2025 target.More impressively,the U-IrRuOx@IrRubased electrolyzer can stably operate for over 550 h,with an extremely low decay rate of 7.52μV h^(-1),corresponding to a predicted lifespan of 23,000 h with 90%performance retention.展开更多
Pd catalyst with high activity and selectivity for O_(2)reduction to H_(2)O_(2)is highly desirable.However,metallic Pd catalyst suffers from limited activity and selectivity in H_(2)O_(2)photosynthesis due to intrinsi...Pd catalyst with high activity and selectivity for O_(2)reduction to H_(2)O_(2)is highly desirable.However,metallic Pd catalyst suffers from limited activity and selectivity in H_(2)O_(2)photosynthesis due to intrinsically strong O_(2)adsorption at Pd atom sites.Herein,a strategy is proposed to modulate the electronic structure,aiming to weaken O_(2)adsorption and further enhance O_(2)-reduction selectivity through the creation of highly dispersed and electron-enriched Pd^(δ-)atom sites.To achieve this,a novel photochemical plating approach is employed to selectively grow vertical Bi nanosheets on the(010)facet of BiVO_(4).This process confines highly dispersed Pd atoms within the Bi nanosheets,forming a PdBi cocatalyst that significantly boosts H_(2)O_(2)photosynthesis.Notably,the optimized PdBi/BiVO_(4)photocatalyst achieves a high H_(2)O_(2)production concentration of 2246.43μmol L−1,with an apparent quantum efficiency(AQE)of 11.16%,realizing a 1.74-fold enhancement in activity compared to Pd/BiVO_(4)(1289.28μmol L^(−1)).Theoretical calculation and experimental results confirm that the vertical-growth Bi nanosheets induce the formation of well-dispersed and electron-enriched Pd^(δ−)atom sites.This accordingly increases the antibonding-orbital occupancy of Pd-O_(ads),thereby weakening O_(2)adsorption and ultimately facilitating selective O_(2)reduction for photocatalytic H_(2)O_(2)production.This rational design of Pd-based catalysts provides a promising strategy for modulating the electronic structure of active atoms to advance artificial photosynthesis.展开更多
Light alkanes non-oxidative dehydrogenation is an attractive non-oil route for olefins production.The alkane dehydrogenation reaction is limited by thermodynamic equilibrium,and the C-H bond cleavage is commonly consi...Light alkanes non-oxidative dehydrogenation is an attractive non-oil route for olefins production.The alkane dehydrogenation reaction is limited by thermodynamic equilibrium,and the C-H bond cleavage is commonly considered as the rate-determined step.The valence state of metal sites in catalysts will influence the stabilization of the vital intermediate(i.e.,C_(x)H_(y)...M^(δ+)...H)during the C-H bond cleavage process,which in turn affects the catalytic reactivity.Herein,we explicitly investigated the effect of different valence states of framework-Fe in silicate-1 zeolite on ethane dehydrogenation reaction through the combination of experimental and theoretical study.Fe(Ⅱ)-S-1 and Fe(Ⅲ)-S-1 catalysts are successfully synthesized by ligand-assisted in situ crystallization method,In-situ C_(2)H_6-FTIR shows the higher coverage of hydrocarbon intermediates on Fe(Ⅱ)-S-1,Under the same evaluation co nditio n,Fe(Ⅱ)-S-1 exhibits a higher space time yield of ethylene.Density functional theory(DFT)results reveal that the more coordinate-unsaturated and electron-enriched Fe(Ⅱ)sites boost the first C-H bond activation by slight deformation and efficient electron donation with C_(2)H_(5)^(*)species.Remarkably,the second C-H bond cleavage on Fe(Ⅱ)-S-1 undergoes a spin-crossing process from quintet state to triplet state,which involves a two-electro n-two-orbital interaction,further promoting the formation of ethylene.Microkinetic analysis is consistent with the experimental and DFT results.This work could provide methodology for elucidating the effect of metal valence states on catalytic performance as well as offer guidance for designing more efficient Fe-zeolite catalysts.展开更多
基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA 0400301)the National Key R&D Program of China(No.2022YFB4002000)+3 种基金the National Natural Science Foundation of China(No.22232004)the Instrument Developing Project of the Chinese Academy of Sciencesthe Jilin Province Development and Reform Commission Program(2023C032-6)the Jilin Province Science and Technology Development Program(No.20240302002ZD,20240101019JC and 20210502002ZP)for financial support。
文摘The development of robust and active oxygen evolution reaction(OER)electrocatalysts is urgently desirable for the widespread implementation of proton exchange membrane water electrolyzers(PEMWE),yet remains a critical challenge.We propose a catalyst named U-IrRuO_(x)@IrRu(where“U”denotes“ultrathin”),which features a spontaneously formed amorphous oxide shell that synergistically optimizes the electronic structure and corrosion resistance.Combined experimental and theoretical studies reveal that the oxyphilic Ru-induced electronic modulation weakens Ir-O binding strength,thereby accelerating the rate-determining step of ^(*)OOH formation.In addition,the metallic alloy core functions as an electron reservoir,suppressing excessive oxidation of active sites while ensuring high conductivity.Due to these attributes,the U-IrRuO_(x)@IrRu demonstrates a low overpotential of 230 mV at 10 mA cm^(-2),outperforming commercial IrO_(2)(CM)by 65 mV.When integrated into a PEMWE with an ultra-low Ir loading of 0.25 mg_(Ir)cm^(-2),it delivers an industrial current density of 2 A cm^(-2)at 1.74 V and 3 A cm^(-2)at 1.836 V,surpassing the U.S.Department of Energy(DOE)2025 target.More impressively,the U-IrRuOx@IrRubased electrolyzer can stably operate for over 550 h,with an extremely low decay rate of 7.52μV h^(-1),corresponding to a predicted lifespan of 23,000 h with 90%performance retention.
基金supported by the National Natural Science Foundation of China(22178276,221760110,22178275)the Postdoctoral Fellowship Program of CPSF(GZC20240888)the Postdoctoral Project of Hubei Province(2024HBBHCXB053).
文摘Pd catalyst with high activity and selectivity for O_(2)reduction to H_(2)O_(2)is highly desirable.However,metallic Pd catalyst suffers from limited activity and selectivity in H_(2)O_(2)photosynthesis due to intrinsically strong O_(2)adsorption at Pd atom sites.Herein,a strategy is proposed to modulate the electronic structure,aiming to weaken O_(2)adsorption and further enhance O_(2)-reduction selectivity through the creation of highly dispersed and electron-enriched Pd^(δ-)atom sites.To achieve this,a novel photochemical plating approach is employed to selectively grow vertical Bi nanosheets on the(010)facet of BiVO_(4).This process confines highly dispersed Pd atoms within the Bi nanosheets,forming a PdBi cocatalyst that significantly boosts H_(2)O_(2)photosynthesis.Notably,the optimized PdBi/BiVO_(4)photocatalyst achieves a high H_(2)O_(2)production concentration of 2246.43μmol L−1,with an apparent quantum efficiency(AQE)of 11.16%,realizing a 1.74-fold enhancement in activity compared to Pd/BiVO_(4)(1289.28μmol L^(−1)).Theoretical calculation and experimental results confirm that the vertical-growth Bi nanosheets induce the formation of well-dispersed and electron-enriched Pd^(δ−)atom sites.This accordingly increases the antibonding-orbital occupancy of Pd-O_(ads),thereby weakening O_(2)adsorption and ultimately facilitating selective O_(2)reduction for photocatalytic H_(2)O_(2)production.This rational design of Pd-based catalysts provides a promising strategy for modulating the electronic structure of active atoms to advance artificial photosynthesis.
基金the financial support from the National Natural Science Foundation of China (22035009,22178381)the National Key R&D Program of China (2021YFA1501301,2021YFC2901100)。
文摘Light alkanes non-oxidative dehydrogenation is an attractive non-oil route for olefins production.The alkane dehydrogenation reaction is limited by thermodynamic equilibrium,and the C-H bond cleavage is commonly considered as the rate-determined step.The valence state of metal sites in catalysts will influence the stabilization of the vital intermediate(i.e.,C_(x)H_(y)...M^(δ+)...H)during the C-H bond cleavage process,which in turn affects the catalytic reactivity.Herein,we explicitly investigated the effect of different valence states of framework-Fe in silicate-1 zeolite on ethane dehydrogenation reaction through the combination of experimental and theoretical study.Fe(Ⅱ)-S-1 and Fe(Ⅲ)-S-1 catalysts are successfully synthesized by ligand-assisted in situ crystallization method,In-situ C_(2)H_6-FTIR shows the higher coverage of hydrocarbon intermediates on Fe(Ⅱ)-S-1,Under the same evaluation co nditio n,Fe(Ⅱ)-S-1 exhibits a higher space time yield of ethylene.Density functional theory(DFT)results reveal that the more coordinate-unsaturated and electron-enriched Fe(Ⅱ)sites boost the first C-H bond activation by slight deformation and efficient electron donation with C_(2)H_(5)^(*)species.Remarkably,the second C-H bond cleavage on Fe(Ⅱ)-S-1 undergoes a spin-crossing process from quintet state to triplet state,which involves a two-electro n-two-orbital interaction,further promoting the formation of ethylene.Microkinetic analysis is consistent with the experimental and DFT results.This work could provide methodology for elucidating the effect of metal valence states on catalytic performance as well as offer guidance for designing more efficient Fe-zeolite catalysts.
