Photoconversion of nitrogen to ammonia by peptidophotocatalyst

Self-assembling peptides are promising in biomedical field; however, they are rarely used in the field of catalysis, let alone for catalytic nitrogen fixation, which has a high energy demand. Here, we demonstrate that a nitrogen coassembling N3y peptide displays highly selective catalytic performance for photoconversion of nitrogen to ammonia in aqueous solutions. Even under natural light conditions, the coassembly system reaches a turnover number of 43.9 based on one molar of N3y within 6 h (61.8 mg gcat-1 h-1) for ammonia formation. This process of nitrogen photoreduction is coupled with water oxidation without the need for sacrificial molecules. Hydrazine, another product of nitrogen reduction, is detected in this photocatalytic system, suggesting that protonation symmetrically occurs on both nitrogen atoms of nitrogen in an alternating fashion.