Nano-intermetallic AuCu₃ catalyst for oxygen reduction reaction: performance and mechanism

This paper introduces a new approach for catalyst design using the non-precious metal Cu as one of the catalytic active centers. This differs from previous studies that considered precious metals to be responsible for the catalytic reaction in precious alloys. Intermetallic AuCu3/C nanoparticles with a diameter of 3 nm were developed for the first time, with uniform dispersion and a narrow size distribution. The ca. 3 nm as-synthesised AuCu3/C showed superior catalytic performance for oxygen reduction reactions (ORR) in alkaline solutions, with comparable half-wave potential and 1.5 times mass current density of commercial Pt/C at 0.80 V (vs. reversible hydrogen electrode (RHE)). The advanced catalytic activities are mainly attributed to the synergetic effects of electro-active atomic Au and Cu on the particle surface, in which Cu helps to activate the O2 molecule and Au benefits OH(-) desorption. The excellent durability and methanol tolerance exhibited in alkaline solutions provide another advantage for AuCu3/C to be considered as a potential alternative cathode catalyst in alkaline fuel cells.