Improving the complete ethanol electrooxidation on Pd-based catalysts in alkaline media has drawn widely attention due to the high mass energy density.However,the weak adsorption energy of CH_(3)CO^(*) on Pd restricts...Improving the complete ethanol electrooxidation on Pd-based catalysts in alkaline media has drawn widely attention due to the high mass energy density.However,the weak adsorption energy of CH_(3)CO^(*) on Pd restricts the C–C bond cleavage.Inspired by the molecular orbital theory,we proposed the d-state-editing strategy to construct more unoccupied d-states of Pd for the enhanced interaction with CH_(3)CO^(*) to break C–C bonds.As expected,the reduced number of e_g electrons and more unoccupied d-states of Pd successfully formed on as-prepared porous Rh Au–Pd Cu nanosheets(PNSs).Theoretical calculations show that the optimized d-states of Rh Au–Pd Cu PNS can effectively improve the adsorption of CH_(3)CO^(*) and drastically reduce the energy barrier of C–C bond cleavage,thus boosting the complete oxidation of ethanol.The charge ratio of C_1 pathway on Rh Au–Pd Cu PNSs is 51.5%,more than 2 times higher than that of Pd NSs.Our finding provides an innovative perspective for the design of highly-efficient noble-based electrocatalysts.展开更多
Developing a catalyst to break the tradeoff relation-ship between the catalytic activity and antipoisoning property toward the ethanol oxidation reaction(EOR)is of critical importance to the development of direct etha...Developing a catalyst to break the tradeoff relation-ship between the catalytic activity and antipoisoning property toward the ethanol oxidation reaction(EOR)is of critical importance to the development of direct ethanol fuel cells(DEFCs),but remains challenging.Here,we developed a unique class of single-site Cu-doped PdSn wavy nanowires(denoted as SS Cu−PdSn WNWs)with promoted activity and durability toward alkaline EOR.Detailed characterizations reveal the atomic isolation of Cu species dispersed on the surface of the PdSn WNWs with distinct wavy structure and grain boundaries.The created SS Cu−PdSn WNWs exhibit an enhanced EOR performance in terms of mass activity,which is higher than those of PdSn WNWs,commercial Pd black,and commercial Pd/C,respectively.Moreover,the SS Cu−PdSn WNWs can also show improved stability as compared to other catalysts due to the improved antipoisoning property from the unique surface anchoring structure.Further investigations demonstrate that the doped SS Cu can strongly inhibit the adsorption of CO and promote the reaction process of EOR.DFT results reveal that the doped Cu shifts down the d-band center of PdSn,thereby modifying the adsorption of intermediates and reducing the reaction barrier of EOR.This work maps a pathway for optimally boosting EOR performance with surface engineering via atomic doping.展开更多
Porous carbon materials were prepared by hydrothermal carbonization(HTC) and KOH activation of camphor leaves and camellia leaves. The morphology, pore structure, chemical properties and CO2 capture ability of the por...Porous carbon materials were prepared by hydrothermal carbonization(HTC) and KOH activation of camphor leaves and camellia leaves. The morphology, pore structure, chemical properties and CO2 capture ability of the porous carbon prepared from the two leaves were compared. The effect of HTC temperature on the structure and CO2 adsorption properties was especially investigated. It was found that HTC temperature had a major effect on the structure of the product and the ability to capture CO2. The porous carbon materials prepared from camellia leaves at the HTC temperature of 240℃ had the highest proportion of microporous structure, the largest specific surface area(up to 1823.77m^2/g) and the maximum CO2 adsorption capacity of 8.30mmol/g at 25℃ under 0.4 MPa. For all prepared porous carbons, simulation results of isothermal adsorption model showed that Langmuir isotherm model described the adsorption equilibrium data better than Freundlich isotherm model. For porous carbons prepared from camphor leaves, pseudo-first order kinetic model was well fitted with the experimental data. However,for porous carbons prepared from camellia leaves, both pseudo-first and pseudo-second order kinetics model adsorption behaviors were present. The porous carbon materials prepared from tree leaves provided a feasible option for CO2 capture with low cost, environmental friendship and high capture capability.展开更多
Heteroatom-doped Pt-based nanocrystals have generated considerable interest and hold great prospects in heterocatalysis. However, engineering the superficial atomic configurations of these nanocrystals via in situ sur...Heteroatom-doped Pt-based nanocrystals have generated considerable interest and hold great prospects in heterocatalysis. However, engineering the superficial atomic configurations of these nanocrystals via in situ surface doping remains exceedingly challenging. Herein, we propose a onepot, in situ surface doping chemical synthesis protocol to prepare quatermetallic Pt Ni Co Rh dendritic nanocrystals as versatile and active catalysts for the electrooxidation of C_(1) fuels. Leveraging the selective coordination effect between ascorbic acid and Rh^(3+)ions, the doping of trace Rh atoms can be guided specifically at the near-surface of Pt Ni Co Rh nanocatalysts. Electrocatalytic tests indicate that Pt_(67)Ni_(16)Co_(16)Rh_(1) nanocrystals with in situ trace Rh-doped surface exhibit substantially enhanced activity, durability, and CO tolerance for the electrooxidation of methanol, formaldehyde, and formic acid. In situ Fourier transform infrared spectroscopy provides molecular-level insight into the exceptional performance of these nanocatalysts. The surface incorporation of anticorrosive Rh atoms enables the transfer of CO intermediates from the atop Pt sites to the bridged Rh–Pt surface sites,thereby facilitating the elimination of these poisoning species from the catalyst surface. This study presents an effective in situ surface doping strategy which can enable the design of more atom-economic heterocatalysts.展开更多
Among all CO2 electroreduction products,methane(CH4)and ethylene(C_(2)H_(4))are two typical and valuable hydrocarbon products which are formed in two different pathways:hydrogenation and dimerization reactions of the ...Among all CO2 electroreduction products,methane(CH4)and ethylene(C_(2)H_(4))are two typical and valuable hydrocarbon products which are formed in two different pathways:hydrogenation and dimerization reactions of the same CO intermediate.Theoretical studies show that the adsorption configurations of CO intermediate determine the reaction pathways towards CH4/C_(2)H_(4).However,it is challenging to experimentally control the CO adsorption configurations at the catalyst surface,and thus the hydrocarbon selectivity is still limited.Herein,we seek to synthesize two well-defined copper nanocatalysts with controllable surface structures.The two model catalysts exhibit a high hydrocarbon selectivity toward either CH4(83%)or C_(2)H_(4)(93%)under identical reduction conditions.Scanning transmission electron microscopy and X-ray absorption spectroscopy characterizations reveal the low-coordination Cu^(0)sites and local Cu^(0)/Cu^(+)sites of the two catalysts,respectively.CO-temperature programed desorption,in-situ attenuated total reflection Fourier transform infrared spectroscopy and density functional theory studies unveil that the bridge-adsorbed CO(CO_(B))on the low-coordination Cu^(0)sites is apt to be hydrogenated to CH4,whereas the bridge-adsorbed CO plus linear-adsorbed CO(CO_(B)+CO_(L))on the local Cu^(0)/Cu^(+)sites are apt to be coupled to C_(2)H_(4).Our findings pave a new way to design catalysts with controllable CO adsorption configurations for high hydrocarbon product selectivity.展开更多
基金supported by the National Natural Science Foundation of China (22322902,U22A20396,22102052,22309050,and 22211540385)the National Key Research and Development Program of China (2021YFA1502000)+3 种基金the Science and Technology Innovation Program of Hunan Province (2021RC3065)Jiebang Guashuai Project of Changsha City (kq2301009)Shenzhen Science and Technology Program (JCYJ20210324120800002,JCYJ20220818100012025,and JCYJ20230807122007015)China Postdoctoral Science Foundation (2023T160205)。
基金financially supported by the National Natural Science Foundation of China (22209039)Top-notch Personnel Fund of Henan Agricultural University (30500682)。
文摘Improving the complete ethanol electrooxidation on Pd-based catalysts in alkaline media has drawn widely attention due to the high mass energy density.However,the weak adsorption energy of CH_(3)CO^(*) on Pd restricts the C–C bond cleavage.Inspired by the molecular orbital theory,we proposed the d-state-editing strategy to construct more unoccupied d-states of Pd for the enhanced interaction with CH_(3)CO^(*) to break C–C bonds.As expected,the reduced number of e_g electrons and more unoccupied d-states of Pd successfully formed on as-prepared porous Rh Au–Pd Cu nanosheets(PNSs).Theoretical calculations show that the optimized d-states of Rh Au–Pd Cu PNS can effectively improve the adsorption of CH_(3)CO^(*) and drastically reduce the energy barrier of C–C bond cleavage,thus boosting the complete oxidation of ethanol.The charge ratio of C_1 pathway on Rh Au–Pd Cu PNSs is 51.5%,more than 2 times higher than that of Pd NSs.Our finding provides an innovative perspective for the design of highly-efficient noble-based electrocatalysts.
基金the National Natural Science Foundation of China(21905188)the major project of Basic Science(natural science)of Jiangsu Province(21KJA430001)+2 种基金the Jiangsu Provincial Natural Science Foundation(BK20211316)the Suzhou Municipal Science and Technology Bureau(SYG202125)the State Key Laboratory of Physical Chemistry of Solid Surfaces,Xiamen University(202113)。
文摘Developing a catalyst to break the tradeoff relation-ship between the catalytic activity and antipoisoning property toward the ethanol oxidation reaction(EOR)is of critical importance to the development of direct ethanol fuel cells(DEFCs),but remains challenging.Here,we developed a unique class of single-site Cu-doped PdSn wavy nanowires(denoted as SS Cu−PdSn WNWs)with promoted activity and durability toward alkaline EOR.Detailed characterizations reveal the atomic isolation of Cu species dispersed on the surface of the PdSn WNWs with distinct wavy structure and grain boundaries.The created SS Cu−PdSn WNWs exhibit an enhanced EOR performance in terms of mass activity,which is higher than those of PdSn WNWs,commercial Pd black,and commercial Pd/C,respectively.Moreover,the SS Cu−PdSn WNWs can also show improved stability as compared to other catalysts due to the improved antipoisoning property from the unique surface anchoring structure.Further investigations demonstrate that the doped SS Cu can strongly inhibit the adsorption of CO and promote the reaction process of EOR.DFT results reveal that the doped Cu shifts down the d-band center of PdSn,thereby modifying the adsorption of intermediates and reducing the reaction barrier of EOR.This work maps a pathway for optimally boosting EOR performance with surface engineering via atomic doping.
基金financially supported by the National Natural Science Foundation of China (Nos. U1760119, 51472160 and U1560108)the Shanghai Nature Science Foundation (No. 16ZR1423400)the Science and Technology Commission of Shanghai Municipality (Nos. 15JC1490700 and 16JC1402200)
文摘Porous carbon materials were prepared by hydrothermal carbonization(HTC) and KOH activation of camphor leaves and camellia leaves. The morphology, pore structure, chemical properties and CO2 capture ability of the porous carbon prepared from the two leaves were compared. The effect of HTC temperature on the structure and CO2 adsorption properties was especially investigated. It was found that HTC temperature had a major effect on the structure of the product and the ability to capture CO2. The porous carbon materials prepared from camellia leaves at the HTC temperature of 240℃ had the highest proportion of microporous structure, the largest specific surface area(up to 1823.77m^2/g) and the maximum CO2 adsorption capacity of 8.30mmol/g at 25℃ under 0.4 MPa. For all prepared porous carbons, simulation results of isothermal adsorption model showed that Langmuir isotherm model described the adsorption equilibrium data better than Freundlich isotherm model. For porous carbons prepared from camphor leaves, pseudo-first order kinetic model was well fitted with the experimental data. However,for porous carbons prepared from camellia leaves, both pseudo-first and pseudo-second order kinetics model adsorption behaviors were present. The porous carbon materials prepared from tree leaves provided a feasible option for CO2 capture with low cost, environmental friendship and high capture capability.
基金supported by the National Natural Science Foundation of China (21771067)the Natural Science Foundation of Fujian Province (2017J06005 and 2019J01058)+3 种基金the Program for New Century Excellent Talents in Fujian Province Universitythe Promotion Program for Young and Middle-aged Teacher in Science and Technology Research of Huaqiao University (ZQN-PY507)the Scientific Research Funds of Huaqiao Universitythe Instrumental Analysis Center of Huaqiao University for the analysis support。
文摘Heteroatom-doped Pt-based nanocrystals have generated considerable interest and hold great prospects in heterocatalysis. However, engineering the superficial atomic configurations of these nanocrystals via in situ surface doping remains exceedingly challenging. Herein, we propose a onepot, in situ surface doping chemical synthesis protocol to prepare quatermetallic Pt Ni Co Rh dendritic nanocrystals as versatile and active catalysts for the electrooxidation of C_(1) fuels. Leveraging the selective coordination effect between ascorbic acid and Rh^(3+)ions, the doping of trace Rh atoms can be guided specifically at the near-surface of Pt Ni Co Rh nanocatalysts. Electrocatalytic tests indicate that Pt_(67)Ni_(16)Co_(16)Rh_(1) nanocrystals with in situ trace Rh-doped surface exhibit substantially enhanced activity, durability, and CO tolerance for the electrooxidation of methanol, formaldehyde, and formic acid. In situ Fourier transform infrared spectroscopy provides molecular-level insight into the exceptional performance of these nanocatalysts. The surface incorporation of anticorrosive Rh atoms enables the transfer of CO intermediates from the atop Pt sites to the bridged Rh–Pt surface sites,thereby facilitating the elimination of these poisoning species from the catalyst surface. This study presents an effective in situ surface doping strategy which can enable the design of more atom-economic heterocatalysts.
基金supported by the National Natural Science Foundation of China (21875042)Shanghai Science and Technology Committee (18QA1400800)+1 种基金the Program of Eastern Scholar at Shanghai Institutions and Yanchang Petroleum Groupsupported by the Frontier Research Center for Materials Structure, School of Materials Science and Engineering of Shanghai Jiao Tong University
文摘Among all CO2 electroreduction products,methane(CH4)and ethylene(C_(2)H_(4))are two typical and valuable hydrocarbon products which are formed in two different pathways:hydrogenation and dimerization reactions of the same CO intermediate.Theoretical studies show that the adsorption configurations of CO intermediate determine the reaction pathways towards CH4/C_(2)H_(4).However,it is challenging to experimentally control the CO adsorption configurations at the catalyst surface,and thus the hydrocarbon selectivity is still limited.Herein,we seek to synthesize two well-defined copper nanocatalysts with controllable surface structures.The two model catalysts exhibit a high hydrocarbon selectivity toward either CH4(83%)or C_(2)H_(4)(93%)under identical reduction conditions.Scanning transmission electron microscopy and X-ray absorption spectroscopy characterizations reveal the low-coordination Cu^(0)sites and local Cu^(0)/Cu^(+)sites of the two catalysts,respectively.CO-temperature programed desorption,in-situ attenuated total reflection Fourier transform infrared spectroscopy and density functional theory studies unveil that the bridge-adsorbed CO(CO_(B))on the low-coordination Cu^(0)sites is apt to be hydrogenated to CH4,whereas the bridge-adsorbed CO plus linear-adsorbed CO(CO_(B)+CO_(L))on the local Cu^(0)/Cu^(+)sites are apt to be coupled to C_(2)H_(4).Our findings pave a new way to design catalysts with controllable CO adsorption configurations for high hydrocarbon product selectivity.
