Preparation of Pt-skin PtRhNi Nanoframes Decorated with Small SnO2 Nanoparticles as an Efficient Catalyst for Ethanol Oxidation Reaction

Abstract

Pt-based nanoframes are one of the most promising catalysts for ethanol oxidation reaction in direct ethanol fuel cells. It is important to understand the mechanisms responsible for creating these hollow nanoframe-based catalysts. Herein, for the first time, Pt-skin PtRhNi rhombic dodecahedral nanoframes were decorated with small SnO2 nanoparticles and were used as an efficient catalyst for the ethanol oxidation reaction. Moreover, by combining the ex situ scanning transmission electron microscopy and energy-dispersive X-ray spectroscopy observations at various stages of synthesis, along with density functional theory calculations, it was possible to track the synthesis route of solid rhombic dodecahedral PtRhNi nanoparticles, which are the precursors of PtRhNi nanoframes. After the chemical etching of the Ni core from solid PtRhNi nanoparticles, the obtained nanoframes were decorated with SnO2 nanoparticles. The resulting SnO2@PtRhNi heteroaggregates were deposited on high-surface-area carbon and electrochemically tested, showing a 6-fold higher mass activity and 10-fold higher specific activity toward ethanol oxidation reaction than commercially available Pt catalysts.