RESUMO
It is desirable to unravel the correlation between the geometric and electronic structures and the activity and further prepare high-performance electrocatalysts. Here in this paper, trimetallic Ru@Au-Pt core-shell nanoparticles were prepared by sequential ethanol reduction method, and further subject to characterization of X-ray diffraction, high angle annular dark field transmission electron microscopy, X-ray photoelectron spectroscopy and electrochemical CO stripping. Further analysis based on Williamson-Hall method revealed that the Au/Pt atomic ratio and shell thickness result in apparent variation of micro-strain and CO binding energy of Ru@AuPt nanoparticles, where the CO oxidation peak potential showed an inverted volcano-shape dependence on the microstrain of the metal nanoparticles while the catalytic activity towards electrooxidation of formic acid is linearly dependent on the micro-strain. The best Ru@Au-Pt catalyst delivers a specific activity of 4.14 mA cm-2, which is 52 times that of Pt/C, respectively. This study indicated that the microstrain and stacking fault of metal nanoparticles might be a good descriptor for the catalytic activity and may shed light the rational design, synthesis and surface engineering towards the high-performance electrocatalyst.
RESUMO
Localized surface plasmon resonance (LSPR) excitation of noble metal nanoparticles has been shown to accelerate and drive photochemical reactions. Here, LSPR excitation is shown to enhance the electrocatalysis of a fuel-cell-relevant reaction. The electrocatalyst consists of Pdx Ag alloy nanotubes (NTs), which combine the catalytic activity of Pd toward the methanol oxidation reaction (MOR) and the visible-light plasmonic response of Ag. The alloy electrocatalyst exhibits enhanced MOR activity under LSPR excitation with significantly higher current densities and a shift to more positive potentials. The modulation of MOR activity is ascribed primarily to hot holes generated by LSPR excitation of the Pdx Ag NTs.