Intermetallic Rhodium Alloy Nanoparticles for Electrocatalysis

The rational design and facile synthesis of highly activated and stable electrocatalysts toward the hydrogen evolution reaction (HER) and the oxygen reduction reaction (ORR) are extremely demanded but remain challenging. Herein, a highly efficient bifunctional electrocatalyst composed of rhodium (Rh), cobalt (Co), and iron (Fe) alloy nanoparticles embedded in nitrogen-doped graphene (RhFeCo@NG) is prepared through sequential annealing and the substitution reaction. The as-prepared Rh2.6Fe3Co2.6@NG electrocatalyst achieves an overpotential as low as 25 mV for reaching a current density of 10 mA cm(-2) and an ultralow Tafel slope of 29.8 mV dec(-1) in 1 M KOH solution for HER, which is even superior to the state-of-the-art platinum (Pt) catalyst. With regard to ORR, for the Rh2.6Fe3Co2.6@NG electrocatalyst, a half-wave potential (E-1(/)2) of 0.82 V versus reversible hydrogen electrode and excellent long-term stability are achieved. The experimental results illustrate that alloying the Rh atom with the FeCo nanoalloy is mainly responsible for the excellent HER and ORR performances. This study not only provides a robust and promising electrocatalyst for HER and ORR in alkaline media but also sheds light on the devising of efficient and multifunctional catalysts.

Automated summary

This study demonstrates the rational design and facile synthesis of a highly efficient bifunctional electrocatalyst composed of Rh, Co, and Fe alloy nanoparticles embedded in nitrogen-doped graphene. The RhFeCo@NG catalyst shows superior performance in the hydrogen evolution reaction and the oxygen reduction reaction compared to state-of-the-art Pt catalyst, highlighting the potential for developing efficient and multifunctional catalysts.