A Mo2-ZnP molecular device that mimics photosystem I for solar-chemical energy conversion

• Published in: Applied catalysis. B, Environmental Environmental, 2021-06, Vol.286, p.119836, Article 119836
• Main Authors: Liu, Xiao, Zhou, Junpeng, Meng, Miao, Zhu, Guang Yuan, Tan, Yingning, Chen, Xiaoli, Wei, Junhua, Kuang, Dai-Bin, Wu, Yi Yang, Su, Shaoyang, Cheng, Tao, Zhou, Yuli, Liu, Chun Y.
• Format: Article
• Language: English
• Subjects: Adenine; Anions; Carbon dioxide; Chemical energy; Chemists; Dimolybdenum complex; Energy conversion; Flavin; Flavin-adenine dinucleotide; Fuel production; Hydrogen evolution; Hydrogent production; Hydroquinone; Intermediates; NAD; NADH; Nicotinamide; Nicotinamide adenine dinucleotide; Photocatalysis; Photocatalyst; Photocatalysts; Photoreduction; Photosynthesis; Photosystem I; Porphyrins; Protons; Reduction; Solar energy; Solar energy conversion; Substrates; Zinc; Zinc porphyrin
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2020.119836

[Display omitted] •A small Mo2-ZnP molecule catalyzes efficient photoreduction of H2O to H2.•Multi electron transfer pathways broaden the energy thresholds of photoreaction.•Coupling two one-electron transfers to two-electron reduction for hydride transfer.•Single molecular photosystems mimicking Photosystem I for conversion of NAD+ to NADH. Bioinspired solar-chemical energy conversion has long been challenged by chemists with searching for effective synthetic photocatalysts. Herein we show that powered by visible light, molecular photocatalysts developed by integrating zinc porphyrin (ZnP) with a quadruply-bonded Mo2 unit enables hydrogen evolution from water in high yields up to 200 mmol g−1 with TON = 640. Remarkably, this unimolecular Mo2-ZnP device catalyzes efficiently photoreduction of nicotinamide adenine dinucleotide (NAD+) to NADH, the reducing equivalent for enzymatic reduction of CO2 in natural photosynthesis. Evidently, this Mo2-ZnP photosystem has the capability of accumulating up to four electrons and two protons for two-electron reduction. Mechanistic investigations reveal that the photoreduced zinc phlorin and chlorin-phlorin anions are the catalytic intermediates for hydride transfer to the substrates, which mimics functionally the hydroquinone state of flavin adenine dinucleotide in photosystem I. The understandings gained in this study are valuable for engineering photocatalysts for solar fuel production.