RhCuBi Trimetallenes with Composition Segregation Coupled Crystalline-Amorphous Heterostructure Toward Ethanol Electrooxidation

The inefficiency of Pt and Pd benchmark catalysts in achieving complete ethanol oxidation, coupled with their inherent susceptibility to poisoning, poses a significant obstacle to the advancement of direct ethanol fuel cells. In this study, the development of self-supported and ultrathin RhCuBi trimetallenes, demonstrating exceptional performance in ethanol electrooxidation through segregation and interface engineering is presented. The distinctive RhBi-rich crystalline/RhCu-rich amorphous heterostructure of RhCuBi trimetallenes creates a wealth of highly active interfacial sites for the ethanol oxidation reaction (EOR). This results in an impressive 43.3% Faradaic efficiency for the C1 pathway and a peak mass activity of 1.11 A mg(Rh)(-1) at 0.68 V versus reversible hydrogen electrode. Moreover, RhCuBi trimetallenes retain 60% of their initial mass activity after 8.5 h of constant potential electrolysis, outperforming commercial Pd and Pt catalysts (<3%). In/ex situ infrared spectroscopy directly reveals the generated C1 products and the key CH3CO* intermediates for EOR on RhCuBi trimetallenes. Theoretical calculations confirm that the RhBi alloy, particularly the lattice-stretched crystalline/amorphous interfacial sites, facilitates the adsorption/activation of ethanol and the dehydrogenation of CH3CO* toward the C1 pathway of EOR. This breakthrough offers promising prospects for enhancing the efficiency and stability of ethanol electrooxidation in fuel cell applications.