Role of synergies of Cu/Fe3O4 electrocatalyst for nitric oxide reduction to ammonia

The electrochemical nitric oxide reduction reaction (NORR) is a promising green process for nitric oxide (NO) removal and ammonia (NH 3 ) synthesis. Among existing catalysts, copper (Cu) exhibits relatively high activity but is less stable and does not provide enough *H to further increase the NH 3 yield. In this study, a Cu/Fe 3 O 4 electrocatalyst with synergistic catalysis was synthesized. Cu contributes to NO activation and sequential hydrogenation, while Fe 3 O 4 promotes the decomposition of H 2 O to provide more *H and jointly promote NH 3 synthesis. The Cu/Fe 3 O 4 shows a high NH 3 yield of 347.5 ± 5.9 μmol h −1 cm −2 at −0.5 V vs. RHE and high Faraday efficiency (FE) of 95.8 ± 0.4 %, superior to most reported non-precious metal catalysts. Moreover, the catalyst activity was not attenuate after the 100 h stability test. The aqueous Zn-NO battery system demonstrates concurrent energy generation and ammonia synthesis capabilities, delivering a peak power output of 9.53 mW cm −2 alongside efficient NH 3 production with a yield of 595.7 ± 5.1 μg h −1 cm −2 .