Electronic Asymmetric Distribution of RhCu Bimetallic Nanocrystals for Enhancing Trifunctional Electrocatalysis

Developing efficient and durable multifunctional electrocatalysts for oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and oxygen reduction reaction (ORR) is of significant importance for many electrochemical energy devices, such as water electrolyzers, metal-air batteries, and fuel cells. Herein, the Rh-Cu alloy nanocrystals (NCs) are prepared with a simple wet-chemical approach. The tuning of morphology and the asymmetric electron distribution provide more efficient Rh-Cu bimetallic sites. Meanwhile, the incorporation of Cu into the Rh lattice could reduce the oxidation of Rh-Cu bimetallic sites and increase the catalytic stability. Under the tuning of the composition, the drastically enhanced electrocatalytic activities of HER, OER, and ORR are achieved in the Rh₆Cu₁ NCs with the cell voltage required to be as low as 1.55 V to accomplish an overall water splitting of 10 mA cm^-2 and a maximum power density of 142.58 mW cm^-2 for a zinc-air battery with good stability, representing the best trifunctional electrocatalysts for all we know. This work highlights the design and control of Rh-Cu NCs, which could be a potential alternative approach to trifunctional catalysis and further boosts the development of the bimetallic electrocatalysts in the energy conversion system.