Kao Chen-Rui | Academia Sinica | Taipei, Taiwan
Abstract
In this work, we demonstrate the one-step aqueous strategy for synthesis of bimetallic Au-Pd nanoicosahedra as the efficient photocatalysts for 4-nitrophenol (4-NP) reduction and fuel cell anodic ethanol oxidation reaction (EOR), by which we tried to examine the optimized nanostructure and composition through tuning [AuCl4−]/[PdCl4−] in the co-reduction process. By turning the molar ratio of Au and Pd precursors, the nanoicosahedra could be made with their cores in close Au-Pd compositions (Pd ~20%) yet their surfaces are largely flexible (Pd: 20-70%). In the model reactions, electrochemical ethanol oxidation and 4-NP reduction, the AuPd (1:1) sample with the surface of Au55Pd45 displayed the most superior activities. By XAS analysis, it brings to light the electronic structures of AuPd nanoicosahedra with Pd-poor surfaces (Au79Pd21 and Au60Pd40) keep Au characteristics while those with Pd-rich surfaces are more Pd-like. The AuPd (1:1) sample (Au83Pd17-Au55Pd45) hence plays a turnover line in-between them, suggesting the best Au-Pd interplay towards catalytic performances. Our findings in catalyst designs at atomic scale will bring deep insights into the fields of nanosynthesis and heterogeneous catalysis, which will be beneficial for further scientific breakthroughs.
