Photo‐driven Ammonia Synthesis via a Proton‐mediated Photoelectrochemical Device

N2 reduction reaction (NRR) by light is an energy‐saving and sustainable ammonia (NH3) synthesis technology. However, it faces significant challenges, including high energy barriers of N2 activation and unclear catalytic active sites. Herein, we propose a strategy of photo‐driven ammonia synthesis via a proton‐mediated photoelectrochemical device. We used redox‐catalysis covalent organic framework (COF), with a redox site (‐C=O) for H+ reversible storage and a catalytic site (porphyrin Au) for NRR. In the proton‐mediated photoelectrochemical device, the COF can successfully store e‐ and H+ generated by hydrogen oxidation reaction, forming COF‐H. Then, these stored e‐ and H+ can be used for photo‐driven NRR (108.97 umol g‐1) under low proton concentration promoted by the H‐bond network formed between ‐OH in COF‐H and N2 on Au, which enabled N2 hydrogenation and NH3 production, establishing basis for advancing artificial photosynthesis and enhancing ammonia synthesis technology.