·H effectively enhance electrocatalytic nitrogen fixation.

Nowadays, most reported ammonia (NH) yields and Faradaic efficiency (FE) of electrocatalysts are very low in the field of electrocatalytic nitrogen reduction reactions (NRR). Here, we are reported ·H for the first time in the field of electrocatalytic NRR, which are generated by sulfite (SO) and HO in electrolyte solutions upon exposure to UV light. The high NH yields can achieve 100.7 μg h mg, while stability can achieve 64 h and the FE can achieve 27.1% at -0.3 V (vs. RHE) with UV irradiation. In situ Fourier transform infrared spectroscopy (FTIR), electron spin resonance (ESR), density functional theory (DFT) and H nuclear magnetic resonance (NMR) tests showed that the ∙H effectively lowered the reaction energy barrier at each step of the NRR process and inhibits the occurrence of competitive hydrogen evolution reaction (HER). This explores the path and provides ideas for the field of electrocatalysis involving water.