The Pt-based catalyst tends to be poisoned by carbon monoxide(CO)-like intermediates produced in fuel cell reactions,which seriously deteriorates its catalytic performance.Herein,noble metal Au with the capacity of re...The Pt-based catalyst tends to be poisoned by carbon monoxide(CO)-like intermediates produced in fuel cell reactions,which seriously deteriorates its catalytic performance.Herein,noble metal Au with the capacity of resistance to CO-like intermediates poisoning was employed to construct multi-element Pt-based catalysts.Two trimetallic NiPtAu hollow nanocrystals(HNCs)with different surface Au contents were synthesized to explore the role of Au in electrocatalysis for alkaline methanol oxidation reaction(MOR).The trimetallic NiPtAu-SRAu HNCs catalyst with the relative rich Au content(15.17 at%)on surface exhibits a much lower CO oxidation peak potential than the other HNCs counterpart and 20 wt%Pt/C,which indicates the more exceptional CO-resisting performance.Besides,the MOR specific activity of NiPtAu-SRAu HNCs(31.52 mA cm^−2)is 7 times higher than that of 20wt%Pt/C(4.50 mA cm^−2).This enhancement in catalytic activity as well as anti-CO poisoning capability for NiPtAu-SRAu HNCs can be mainly ascribed to the weakened CO adsorption due to the exposure of Au atoms on NiPt surface evidenced by the experimental data and density functional theory calculations.This study not only investigates the role of Au in MOR catalysis but also could be helpful for designing and optimizing the electrocatalysts for high-active and robust fuel cell applications.展开更多
All inorganic metal halide perovskite nanocrystals(NCs)have attracted much attention for their outstanding optoelectronic properties,which can be tuned by the composition,surface,size and morphology in nanoscale.Herei...All inorganic metal halide perovskite nanocrystals(NCs)have attracted much attention for their outstanding optoelectronic properties,which can be tuned by the composition,surface,size and morphology in nanoscale.Herein,we report the microfluidic synthesis of hollow CsPbBr_(3)perovskite NCs through the nanoscale Kirkendall effect.The formation mechanism of the hollow structure(Kirkendall void)controlled by the temperature,flow rate,ratios of precursors and ligands was investigated.Compared with the solid CsPbBr_(3)NCs of the same size,the hollow CsPbBr_(3)NCs exhibit blue shifts in ultraviolet-visible(UV-vis)absorption and photoluminescence(PL)spectra,and remarkably longer PL average lifetime(~98.2 ns).Quantum confinement effect,inner surface induced additional trap states and lattice strain of the hollow CsPbBr_(3)NCs were discussed in understanding their unique optoelectronic properties.The hollow CsPbBr_(3)NC based photodetector exhibits an outstanding negative photoconductivity(NPC)detectivity of 8.9×10^(12)Jones.They also show potentials in perovskite NC based photovoltaic and light emitting diodes(LEDs).展开更多
基金the National Natural Science Foundation of China(91963113,51701139,51671143 and U1601216)。
文摘The Pt-based catalyst tends to be poisoned by carbon monoxide(CO)-like intermediates produced in fuel cell reactions,which seriously deteriorates its catalytic performance.Herein,noble metal Au with the capacity of resistance to CO-like intermediates poisoning was employed to construct multi-element Pt-based catalysts.Two trimetallic NiPtAu hollow nanocrystals(HNCs)with different surface Au contents were synthesized to explore the role of Au in electrocatalysis for alkaline methanol oxidation reaction(MOR).The trimetallic NiPtAu-SRAu HNCs catalyst with the relative rich Au content(15.17 at%)on surface exhibits a much lower CO oxidation peak potential than the other HNCs counterpart and 20 wt%Pt/C,which indicates the more exceptional CO-resisting performance.Besides,the MOR specific activity of NiPtAu-SRAu HNCs(31.52 mA cm^−2)is 7 times higher than that of 20wt%Pt/C(4.50 mA cm^−2).This enhancement in catalytic activity as well as anti-CO poisoning capability for NiPtAu-SRAu HNCs can be mainly ascribed to the weakened CO adsorption due to the exposure of Au atoms on NiPt surface evidenced by the experimental data and density functional theory calculations.This study not only investigates the role of Au in MOR catalysis but also could be helpful for designing and optimizing the electrocatalysts for high-active and robust fuel cell applications.
基金supported by the National Natural Science Foundation of China(Nos.22175095 and 62175112)the National Key R&D Program of China(No.2022YFA1204404).
文摘All inorganic metal halide perovskite nanocrystals(NCs)have attracted much attention for their outstanding optoelectronic properties,which can be tuned by the composition,surface,size and morphology in nanoscale.Herein,we report the microfluidic synthesis of hollow CsPbBr_(3)perovskite NCs through the nanoscale Kirkendall effect.The formation mechanism of the hollow structure(Kirkendall void)controlled by the temperature,flow rate,ratios of precursors and ligands was investigated.Compared with the solid CsPbBr_(3)NCs of the same size,the hollow CsPbBr_(3)NCs exhibit blue shifts in ultraviolet-visible(UV-vis)absorption and photoluminescence(PL)spectra,and remarkably longer PL average lifetime(~98.2 ns).Quantum confinement effect,inner surface induced additional trap states and lattice strain of the hollow CsPbBr_(3)NCs were discussed in understanding their unique optoelectronic properties.The hollow CsPbBr_(3)NC based photodetector exhibits an outstanding negative photoconductivity(NPC)detectivity of 8.9×10^(12)Jones.They also show potentials in perovskite NC based photovoltaic and light emitting diodes(LEDs).
