Improving the Electrocatalytic Activity of Pt Monolayer Catalysts for Electrooxidation of Methanol, Ethanol and Ammonia by Tailoring the Surface Morphology of the Supporting Core

Pt-monolayer-decorated Au particles with different surface morphologies were prepared by Au electrodeposition, followed by Cu under-potential deposition and a Pt replacement reaction. Spherical Au particles with relatively smooth surfaces and flower-like Au particles consisting of interconnecting thin nanosheets were obtained by controlling the deposition potential and electrolyte concentration. Pt-monolayer-decorated flower-like Au particles exhibit much higher specific activity and stability in the electrooxidation of methanol, ethanol and ammonia compared to Pt-monolayer-decorated spherical Au particles. Pt-monolayer-decorated flower-like Au particles also showed better poisoning-tolerance, especially in the electrooxidation of methanol. The improved electrocatalytic performance is attributed to the high density of catalytically active sites such as surface atomic steps, the edges at sharp tips and edges on the surface of the flower-like particles, which is revealed by spherical-aberration-corrected transmission electron microscopy with atomic resolution.