Multi‐functional high‐entropy alloys and oxides for self‐powered electrocatalytic nitrate reduction to ammonia

High‐entropy alloys (HEAs) show high activities toward oxygen reduction reaction (ORR), Zn‐air batteries (ZABs) and nitrate reduction reaction (NO3−RR). In this work, FeNiCoMnRh HEA supported by N‐doped carbon frameworks is prepared and showed excellent ORR performance with a half‐wave potential (E1/2) of 0.89 V vs. RHE, limiting diffusion current (jL) of 5.6 mA cm‐2 and better current stability. The HEA‐assembled ZAB exhibited a high‐power density of 103.8 mW cm‐2 with a specific capacity of 790 mAh gZn‐1. Also, its oxides presented 77% Faraday efficiency (FE) for ammonia production at ‐0.3 V vs. RHE. Accordingly, our designed ZAB was employed to drive NO3−RR to construct a self‐powered system, which provides an attractive route for low‐energy sewage treatment and environmentally friendly preparation of ammonia.