Pt based materials are the most efficient electrocatalysts for the oxygen reduction reaction(ORR)and methanol oxidation reaction(MOR)in fuel cells.Maximizing the utilization of Pt based materials by modulating their m...Pt based materials are the most efficient electrocatalysts for the oxygen reduction reaction(ORR)and methanol oxidation reaction(MOR)in fuel cells.Maximizing the utilization of Pt based materials by modulating their morphologies to expose more active sites is a fundamental objective for the practical application of fuel cells.Herein,we report a new class of hierarchically skeletal Pt-Ni nanocrystals(HSNs)with a multi-layered structure,prepared by an inorganic acid-induced solvothermal method.The addition of H_(2)SO_(4)to the synthetic protocol provides a critical trigger for the successful growth of Pt-Ni nanocrystals with the desired structure.The Pt-Ni HSNs synthesized by this method exhibit enhanced mass activity of 1.25 A mgpt−1 at 0.9 V(versus the reversible hydrogen electrode)towards ORR in 0.1-M HClO_(4),which is superior to that of Pt-Ni multi-branched nanocrystals obtained by the same method in the absence of inorganic acid;it is additionally 8.9-fold higher than that of the commercial Pt/C catalyst.Meanwhile,it displays enhanced stability,with only 21.6%mass activity loss after 10,000 cycles(0.6–1.0 V)for ORR.Furthermore,the Pt-Ni HSNs show enhanced activity and anti-toxic ability in CO for MOR.The superb activity of the Pt-Ni HSNs for ORR and MOR is fully attributed to an extensively exposed electrochemical surface area and high intrinsic activity,induced by strain effects,provided by the unique hierarchically skeletal alloy structure.The novel open and hierarchical structure of Pt-Ni alloy provides a promising approach for significant improvements of the activity of Pt based alloy electrocatalysts.展开更多
Methyl 2-furoate(FAME2)is a model for the potential renewable biofuel of dimethyl furan-2,5-dicarboxylate,with the development of its new synthesis method.The potential energy surfaces of H-abstractions and OHaddition...Methyl 2-furoate(FAME2)is a model for the potential renewable biofuel of dimethyl furan-2,5-dicarboxylate,with the development of its new synthesis method.The potential energy surfaces of H-abstractions and OHadditions between FAME2 and hydroxyl radical(OH)were studied using CCSD(T)/CBS//M062X/ccpVTZ.The subsequent isomerization and decomposition reactions were also determined for the primary radicals produced.The results showed that H-abstraction on the branched methyl group was the dominant channel and that the OH-addition reactions on the furan ring had a significant pressure dependency.The rate coefficients presented here provide important kinetic data to support future improvement of the combustion mechanism of FAME2,and present a sound basis for further research into practical fuels.展开更多
文摘Pt based materials are the most efficient electrocatalysts for the oxygen reduction reaction(ORR)and methanol oxidation reaction(MOR)in fuel cells.Maximizing the utilization of Pt based materials by modulating their morphologies to expose more active sites is a fundamental objective for the practical application of fuel cells.Herein,we report a new class of hierarchically skeletal Pt-Ni nanocrystals(HSNs)with a multi-layered structure,prepared by an inorganic acid-induced solvothermal method.The addition of H_(2)SO_(4)to the synthetic protocol provides a critical trigger for the successful growth of Pt-Ni nanocrystals with the desired structure.The Pt-Ni HSNs synthesized by this method exhibit enhanced mass activity of 1.25 A mgpt−1 at 0.9 V(versus the reversible hydrogen electrode)towards ORR in 0.1-M HClO_(4),which is superior to that of Pt-Ni multi-branched nanocrystals obtained by the same method in the absence of inorganic acid;it is additionally 8.9-fold higher than that of the commercial Pt/C catalyst.Meanwhile,it displays enhanced stability,with only 21.6%mass activity loss after 10,000 cycles(0.6–1.0 V)for ORR.Furthermore,the Pt-Ni HSNs show enhanced activity and anti-toxic ability in CO for MOR.The superb activity of the Pt-Ni HSNs for ORR and MOR is fully attributed to an extensively exposed electrochemical surface area and high intrinsic activity,induced by strain effects,provided by the unique hierarchically skeletal alloy structure.The novel open and hierarchical structure of Pt-Ni alloy provides a promising approach for significant improvements of the activity of Pt based alloy electrocatalysts.
基金This work was supported by the National Natural Science Foundation of China(No.51776045,No.51676176 and No.51976207)the Project was also sponsored by the Scientific Research Foundation of Guangxi University(No.XGZ170074)the Foundation of State Key Laboratory of Coal Combustion(No.FSKLCCA1908).The numerical calculations in this work were performed on the supercomputing system in the Supercomputing Center of the University of Science and Technology of China.
文摘Methyl 2-furoate(FAME2)is a model for the potential renewable biofuel of dimethyl furan-2,5-dicarboxylate,with the development of its new synthesis method.The potential energy surfaces of H-abstractions and OHadditions between FAME2 and hydroxyl radical(OH)were studied using CCSD(T)/CBS//M062X/ccpVTZ.The subsequent isomerization and decomposition reactions were also determined for the primary radicals produced.The results showed that H-abstraction on the branched methyl group was the dominant channel and that the OH-addition reactions on the furan ring had a significant pressure dependency.The rate coefficients presented here provide important kinetic data to support future improvement of the combustion mechanism of FAME2,and present a sound basis for further research into practical fuels.
