Carbon supported PtNiCu nanostructured particles for the electro-oxidation of ethanol in acid environment

Abstract

Four carbon supported trimetallic PtNiCu nanostructured catalysts have been successfully synthesized by a two-step chemical/electrochemical reduction route. Nanoparticles with average sizes in the range of 2.2–3.5 nm with mixed alloy, pseudo core-shell and core-shell patterns were obtained. All as-prepared electrocatalysts exhibited high electroactive surface areas, ranging from 93 to 117 m2 g−1. The electrocatalytic activity of the trimetallic materials towards the ethanol oxidation reaction (EOR) was studied by cyclic voltammetry and chronoamperometry at temperatures between 20 and 60 °C. Among the studied catalysts, the alloy nanomaterial with a Pt:Cu:Ni surface atomic ratio of 36.8:57.0:6.2 and the pseudo core-shell material with a Pt:Cu:Ni surface atomic ratio of 18.0:43.6:38.4 exhibited the best performance for the EOR. These nanostructured catalysts presented lower onset potentials, four times higher mass activities, and 8–10 times higher specific activities than a commercial PtRu/C catalyst. The kinetic parameters (i.e., Tafel slope and apparent activation energy) indicated that the electro-oxidation of ethanol on the as-prepared catalysts was faster than on PtRu/C.