Enhanced activity of Pt-based electrocatalysts for oxygen reduction via a selective Pt deposition process

Carbon-supported Pt nanoparticles with various loading of Pt are prepared by a novel seed-mediated growth method using hydroquinone (HQ) assisted selective deposition. The structural and morphological dependence of the Pt nanoparticles on the catalytic activity in oxygen reduction reaction (ORR) is investigated. The analysis of core-level X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS) cannot elucidate the origin of the large enhancement of the ORR activity. In contrast, electrochemical measurements of the CO-displacement charge and the concomitant CO adlayer oxidation behavior prove that the selective deposition of additional Pt contributed to the decrease of surface defects and to the increase of the onset potential for OH adsorption.

► Hydroquinone assisted seed-mediated growth of Pt nanoparticles.
► The oxygen reduction activity increased together with the amount of extra Pt deposited.
► The increase of catalytic activity originated from the decrease of surface defects.