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

Abstract

This work shows a novel artificial donor-catalyst-acceptor triad photosystem based on a mononuclear C5 H5 -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 C5 H5 -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 Ru(2+) 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.

Isolated Square‐Planar Copper Center in Boron Imidazolate Nanocages for Photocatalytic Reduction of CO2 to CO

“…Thes hortened lifetime reveals the rapid transfer of photogenerated electron from [Ru(bpy) 3 ]Cl 2 to BIF-29, and thereby suppresses the recombination of photogenerated electron and hole pair. [14,18] These results indicate that BIF-29 can effectively promote charge transfer and separation. To further elucidate the charge transfer property,p hotoelectrochemical measurements were performed on as-prepared samples in dark and light at ab ias of 0.7 Vv ersus RHE.…”

“…Thus,t he excited photosensitizer is quenched by BIF-29 via an oxidative quenching. [14,18] These results indicate that BIF-29 can effectively promote charge transfer and separation. Thee mission of photosensitizer in aqueous solution follows one exponential decay with al ifetime of 271 ns.A no bvious decay of the singlet excited state is observed when adding BIF-29 to the solution ( Figure S12c).…”

Coupling metal oxide nanoparticle catalysts for water oxidation to molecular light absorbers

“…The thermally relaxed low spin MMCT state so formed requires spin change upon back electron transfer to high spin ground state, a process that is sufficiently slow for hole transfer from the oxidized donor center to a catalyst to become competitive. In the case of the ZrOCo-IrOx assembly, once the Co is reduced, back transfer of the electron from Zr III is blocked, rendering the reduced Zr sufficiently long lived to activate CO2.A similar case of very slow back electron transfer of 9.8 µs upon visible light excitation of an oxo-bridged system consisting the complex C5H5-RuH covalently attached to a TiO2 nanoparticle surface (anatase) was recently reported by Long[30]. The long residence time of electrons on TiO2 uponphoto-induced Ru II -O-TiO2 metal-to-particle charge-transfer affords CO2 reduction to methane while water is oxidized to O2 at the Ru center, as demonstrated by 13 C and18 O isotopic labeling.…”

“…The long residence time of electrons on TiO2 uponphoto-induced Ru II -O-TiO2 metal-to-particle charge-transfer affords CO2 reduction to methane while water is oxidized to O2 at the Ru center, as demonstrated by 13 C and18 O isotopic labeling. Femtosecond infrared spectroscopy confirmed direct optical electron transfer from Ru center to TiO2 particle[30].The photodeposition method for coupling hetero binuclear light absorbers to metal oxide nanocluster catalysts has recently been expanded to the reduction (acceptor) side of these units.Spatially directed growth of a cuprous oxide nanocluster catalyst adjacent to the Zr center of ZrOCo II units in mesoporous silica was accomplished by photoexcitation of the MMCT absorption in the presence of Cu II (NCCH3)4 precursor. Conversion to Cu I (NCCH3)n (n < 3) by electron transfer from transient Zr III was observed by UV-vis and FT-IR spectroscopy, as shown in…”

The Pros and Cons of Polydopamine-Sensitized Titanium Oxide for the Photoreduction of CO2

“…Limited by its wide bandgap (e.g., 3.2 eV for anatase), however, TiO 2 can only absorb UV light of the solar spectrum which is only~4% of the total solar energy. Various methods, including impurity doping, surface sensitization, oxygen vacancies, and the localized surface plasmon resonance (SPR) effect have been developed to improve the light-harvesting ability of TiO 2 under visible light which accounts for 45% of energy in the solar spectrum [12][13][14][15][16][17][18][19][20]. Among them,…”