Ternary CoPtAu Nanoparticles as a General Catalyst for Highly Efficient Electro-oxidation of Liquid Fuels

Abstract

Efficient electro-oxidation of formic acid, methanol, and ethanol is challenging owing to the multiple chemical reaction steps required to accomplish full oxidation to CO₂ . Herein, a ternary CoPtAu nanoparticle catalyst system is reported in which Co and Pt form an intermetallic L1₀ -structure and Au segregates on the surface to alloy with Pt. The L1₀ -structure stabilizes Co and significantly enhances the catalysis of the PtAu surface towards electro-oxidation of ethanol, methanol, and formic acid, with mass activities of 1.55 A/mg_Pt , 1.49 A/mg_Pt , and 11.97 A/mg_Pt , respectively in 0.1 m HClO₄ . The L1₀ -CoPtAu catalyst is also stable, with negligible degradation in mass activities and no obvious Co/Pt/Au composition changes after 10 000 potential cycles. The in situ surface-enhanced infrared absorption spectroscopy study indicates that the ternary catalyst activates the C-C bond more efficiently for ethanol oxidation.

Keywords: C−C bond cleavage; electro-oxidation; in situ studies; intermetallic structures; nanoparticles; ternary nanoparticles.