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

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 ms result in a long-lived D+-C-A(-) charge-separated state responsible for the solar-fuel production.