Rh–Cu alloy nano-dendrites with enhanced electrocatalytic ethanol oxidation activity

Abstract

The application of direct ethanol fuel cell (DEFC) has been bottlenecked by the sluggish ethanol oxidation reaction (EOR). Efficient electrocatalysts for the C−C bond cleavage are essential to promote EOR with high efficiency and C1 selectivity. Here, we prepared Rh–Cu alloy nano-dendrites (RhCu NDs) with abundant surface steps through controlled co-reduction, which exhibited significantly enhanced activity and C1 selectivity (0.47 mA cm−2(ECSA), 472.4 mA mgRh−1, and 38.9%) than Rh NDs (0.32 mA cm−2(ECSA), 322.1 mA mgRh−1, and 21.4%) and commercially available Rh/C (0.18 mA cm−2(ECSA), 265.4 mA mgRh−1, and 14.9%). Theoretical calculations and CO-stripping experiments revealed that alloying with Cu could modulate the surface electronic structures of Rh to resist CO-poisoning while strengthening ethanol adsorption. In situ Fourier transform infrared spectroscopy (FTIR) indicated that the surface steps on RhCu NDs further promoted the C−C bond cleavage to increase the C1 selectivity. Therefore, optimizing the surface geometric and electronic structures of nanocrystals by rational composition and morphology control can provide a promising strategy for developing practical DEFC devices.