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.