A Long-Lived Mononuclear Cyclopentadienyl Ruthenium Complex Grafted onto Anatase TiO2 for Efficient CO2 Photoreduction

• Published in: Angewandte Chemie International Edition 2016-07, Vol.55 (29), p.8314-8318
• Main Authors: Huang, Haowei, Lin, Jinjin, Zhu, Gangbei, Weng, Yuxiang, Wang, Xuxu, Fu, Xianzhi, Long, Jinlin
• Format: Article
• Language: English
• Subjects: Anatase; Carbon dioxide; Catalysts; Cations; charge-separated state; CO2 reduction; Fuel production; Grafting; Half-life; Injection; Irradiation; Light effects; Light irradiation; Methane; Nuclear fuels; Oxidation; photocatalysis; Photochemistry; Photoreduction; Photosystem; Quantum efficiency; Radiation; Recombination; Ruthenium; ruthenium complexes; Titanium dioxide; Titanium oxides
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201602796

This work shows a novel artificial donor–catalyst–acceptor triad photosystem based on a mononuclear C5H5‐RuH complex oxo‐bridged TiO2 hybrid for efficient CO2 photoreduction. An impressive quantum efficiency of 0.56 % for CH4 under visible‐light irradiation was achieved over the triad photocatalyst, in which TiO2 and C5H5‐RuH serve as the electron collector and CO2‐reduction site and the photon‐harvester and water‐oxidation site, respectively. The fast electron injection from the excited Ru2+ cation to TiO2 in ca. 0.5 ps and the slow backward charge recombination in half‐life of ca. 9.8 μs result in a long‐lived D+–C–A− charge‐separated state responsible for the solar‐fuel production. Injector seat: A Ru complex bound to a TiO2 surface can be locally excited by visible light to rapidly inject electrons into the TiO2 host, in approximately 0.5 ps. The resulting long‐lived charge‐separated state with a half‐life of 9.8 μs implements the CO2‐to‐CH4 reduction with H2O at a quantum yield of 0.56 % and almost 100 % selectivity.