Pt-based catalysts are the typical industrial catalysts for propane dehydrogenation(PDH),which still suffer from insufficient lo ng-term durability due to the structu ral instability and coke deposition.A commercial ...Pt-based catalysts are the typical industrial catalysts for propane dehydrogenation(PDH),which still suffer from insufficient lo ng-term durability due to the structu ral instability and coke deposition.A commercial γ-Al_(2)O_(3) supported thermally robust sub-nanometer Pt2In3intermetallic catalyst with atomically ordered structure and rigorously separated Pt single atoms was fabricated,which showed outstanding robustness in 240 h long-term operation at 600℃ with the deactivation rate constant kdas low as0.00078 h^(-1), ranking among the lowest reported values.Based on various in situ characterizations and theoretical calculations,it was proved that the catalyst stability not only resulted from the separated Pt single-atom sites but also significantly affected by the distance of adjacent Pt atoms.An increasing distance to 3.25 A in the Pt_(2)In_(3)could induce a weak π-adsorption configuration of propylene on Pt sites,which facilitated the desorption of propylene and restrained the side reactions like coking.展开更多
The development of active yet stable catalysts for oxygen reduction reaction(ORR)is still a major issue for the extensive permeation of fuel cells into everyday technology.While nanostructured Pt catalysts are to date...The development of active yet stable catalysts for oxygen reduction reaction(ORR)is still a major issue for the extensive permeation of fuel cells into everyday technology.While nanostructured Pt catalysts are to date the best available systems in terms of activity,the same is not true for stability,particularly under operating conditions.In this work,Pt_(Х)Y alloy nanoparticles are proposed as active and durable electrocatalysts for ORR.Pt_(Х)Y nanoalloys are synthesized and further optimized by laser ablation in liquid followed by laser fragmentation in liquid.The novel integrated laser-assisted methodology succeeded in producing Pt_(Х)Y nanoparticles with the ideal size(<10 nm)of commercial Pt catalysts,yet resulting remarkably more active with E_(1/2)=0.943 V vs.RHE,specific activity=1095μA cm^(-2) and mass activity>1000 A g^(-1).At the same time,the nanoalloys are embedded in a fine Pt oxide matrix,which allows a greater stability of the catalyst than the commercial Pt reference,as directly verified on a gas diffusion electrode.展开更多
Heterogeneous nanocomposites comprising chemically distinct constituents are particularly promising in electrocatalysis.We herein report a synthetic strategy that combines the reduction of Pt and Co ionic precursors a...Heterogeneous nanocomposites comprising chemically distinct constituents are particularly promising in electrocatalysis.We herein report a synthetic strategy that combines the reduction of Pt and Co ionic precursors at an appropriate ratio with the subsequent phosphating at an elevated temperature for forming heterogeneous nanocomposites consisting of quasi-spherical Pt_(3)Co alloy domains and rod-like CoP_(2) domains for high-efficiency methanol electrooxidation.The strong electronic coupling between Pt_(3)Co and CoP_(2) domains in the nanocomposites render the electron density around Pt atoms to decrease,which is favorable for reducing the adsorption of poisoning CO-like intermediates on the catalyst surfaces.Accordingly,the as-prepared heterogeneous Pt_(3)Co–CoP_(2) nanocomposites show good performance for methanol electrooxidation both in acidic and alkaline media.In specific,at a Pt loading of only 6.4%on a common carbon substrate,the mass-based activity of Pt_(3)Co–CoP_(2) nanocomposites in an acidic medium is about 2 and 1.5 times as high as that of commercial Pt/C catalyst(20%mass loading)and home-made Pt_(3)Co alloy nanoparticles(8.0%mass loading),while in the alkaline medium,these values are 3 and 2,respectively.展开更多
基金financially supported by the DNL Cooperation Fund,CAS (DNL202002)the National Natural Science Foundation of China (22102180)+3 种基金the CAS Project for Young Scientists in Basic Research,(YSBR-022)the Key Research Program of Frontier Sciences,CAS (ZDBS-LY-7012)Liao Ning Revitalization Talents Program (XLYC2007070)the Fundamental Research Funds for the Central Universities (20720220009)。
文摘Pt-based catalysts are the typical industrial catalysts for propane dehydrogenation(PDH),which still suffer from insufficient lo ng-term durability due to the structu ral instability and coke deposition.A commercial γ-Al_(2)O_(3) supported thermally robust sub-nanometer Pt2In3intermetallic catalyst with atomically ordered structure and rigorously separated Pt single atoms was fabricated,which showed outstanding robustness in 240 h long-term operation at 600℃ with the deactivation rate constant kdas low as0.00078 h^(-1), ranking among the lowest reported values.Based on various in situ characterizations and theoretical calculations,it was proved that the catalyst stability not only resulted from the separated Pt single-atom sites but also significantly affected by the distance of adjacent Pt atoms.An increasing distance to 3.25 A in the Pt_(2)In_(3)could induce a weak π-adsorption configuration of propylene on Pt sites,which facilitated the desorption of propylene and restrained the side reactions like coking.
基金the P-DISC Grant PROMETEO(project number:P-DiSC#03NExuS_BIRD2021-UNIPD)DYNAMO(project number:P-P-DiSC#01BIRD2020-UNIPD)the financial support of the Fellowship in Applied Electrochemistry 2020。
文摘The development of active yet stable catalysts for oxygen reduction reaction(ORR)is still a major issue for the extensive permeation of fuel cells into everyday technology.While nanostructured Pt catalysts are to date the best available systems in terms of activity,the same is not true for stability,particularly under operating conditions.In this work,Pt_(Х)Y alloy nanoparticles are proposed as active and durable electrocatalysts for ORR.Pt_(Х)Y nanoalloys are synthesized and further optimized by laser ablation in liquid followed by laser fragmentation in liquid.The novel integrated laser-assisted methodology succeeded in producing Pt_(Х)Y nanoparticles with the ideal size(<10 nm)of commercial Pt catalysts,yet resulting remarkably more active with E_(1/2)=0.943 V vs.RHE,specific activity=1095μA cm^(-2) and mass activity>1000 A g^(-1).At the same time,the nanoalloys are embedded in a fine Pt oxide matrix,which allows a greater stability of the catalyst than the commercial Pt reference,as directly verified on a gas diffusion electrode.
基金supported by the Beijing Natural Science Foundation(Grant No.Z200012)National Natural Science Foundation of China(Grant Nos.22075290,21972068,21776292,21706265)+1 种基金State Key Laboratory of Multiphase Complex Systems,Institute of Process Engineering,Chinese Academy of Sciences(MPCS-2019-A-09)Nanjing IPE Institute of Green Manufacturing Industry are gratefully acknowledged.
文摘Heterogeneous nanocomposites comprising chemically distinct constituents are particularly promising in electrocatalysis.We herein report a synthetic strategy that combines the reduction of Pt and Co ionic precursors at an appropriate ratio with the subsequent phosphating at an elevated temperature for forming heterogeneous nanocomposites consisting of quasi-spherical Pt_(3)Co alloy domains and rod-like CoP_(2) domains for high-efficiency methanol electrooxidation.The strong electronic coupling between Pt_(3)Co and CoP_(2) domains in the nanocomposites render the electron density around Pt atoms to decrease,which is favorable for reducing the adsorption of poisoning CO-like intermediates on the catalyst surfaces.Accordingly,the as-prepared heterogeneous Pt_(3)Co–CoP_(2) nanocomposites show good performance for methanol electrooxidation both in acidic and alkaline media.In specific,at a Pt loading of only 6.4%on a common carbon substrate,the mass-based activity of Pt_(3)Co–CoP_(2) nanocomposites in an acidic medium is about 2 and 1.5 times as high as that of commercial Pt/C catalyst(20%mass loading)and home-made Pt_(3)Co alloy nanoparticles(8.0%mass loading),while in the alkaline medium,these values are 3 and 2,respectively.
