Author, as appears in the article.: Wang F; Neumann R; De Graaf C; Poblet JM
Department: Química Física i Inorgànica
URV's Author/s: De Graaf, Cornelis / Poblet Rius, Josep Maria / Wang, Fei
Keywords: Rhenium Polyoxometalates Hydrocarbon dehydrogenation Hybrid complexes Graphitic carbon nitride Dft Co2 photoreduction Co photoreduction 2
Abstract: © 2021 American Chemical Society. The mechanism of the photochemical reduction of carbon dioxide to carbon monoxide coupled to hydrocarbon dehydrogenation catalyzed by a three-component hybrid construct has been studied by combining density functional theory and complete active space self-consistent field/CASPT2 calculations. The electron and proton coupled transfer mechanism is summarized as follows. Graphitic carbon nitride (g-CN), as the photosensitive semiconductor, absorbs visible blue light and transfers electrons to polyoxometalate (POM), a process that is driven by the relative energy of the lowest unoccupied molecular orbital levels of the two species. Then, the hydrocarbon substrate (cyclohexene or cyclohexadiene) is dehydrogenated by the effect of holes formed during the photoexcitation of g-CN, which leads to the transfer of electrons to the oxidized g-CN and protons to the reduced POM. Under red light irradiation, the reduced POM transfers two electrons to the bimetallic rhenium [Re(I)] CO2 reduction catalyst {[Re1(bipyNNH2)(CO)3Cl-Re2(bipy)(CO)3Cl], bipy = 2,2′-bipyridine}. The activated catalyst reduces CO2 to CO, while the proton-rich POM transfers two protons to generate the reduction co-product, H2O. Acting as an electron/proton switch, POM promotes hydrocarbon dehydrogenation by increasing the electron/hole separation upon photoactivation of g-CN and facilitates the transfer of electrons and protons to the Re catalyst for CO2 reduction. The first electron transfer to the Re complex is to the bipyNNH2 ligand. The unpaired electron is then transferred to the Re 5dz2 orbital, activating the coordination of CO2. The combination of a strong interaction between the nearly degenerate d-π∗ orbitals of Re and the bipyNNH2 ligand, the low reduction potential of -0.85 V, and an extremely low free energy barrier of +2.4 kcal mol-1 for CO2 ligation makes the bimetallic Re compound one of the best catalysts for transforming CO2 to CO.
Thematic Areas: Química Materiais Interdisciplinar General chemistry Engenharias ii Ciências agrárias i Chemistry, physical Chemistry (miscellaneous) Chemistry (all) Catalysis Astronomia / física
licence for use: https://creativecommons.org/licenses/by/3.0/es/
Author's mail: coen.degraaf@urv.cat fei.wang@urv.cat josepmaria.poblet@urv.cat
Author identifier: 0000-0001-8114-6658 0000-0001-5106-5793 0000-0002-4533-0623
Record's date: 2024-07-27
Papper version: info:eu-repo/semantics/acceptedVersion
Licence document URL: https://repositori.urv.cat/ca/proteccio-de-dades/
Papper original source: Acs Catalysis. 11 (3): 1495-1504
APA: Wang F; Neumann R; De Graaf C; Poblet JM (2021). Photoreduction Mechanism of CO2to CO Catalyzed by a Three-Component Hybrid Construct with a Bimetallic Rhenium Catalyst. Acs Catalysis, 11(3), 1495-1504. DOI: 10.1021/acscatal.0c04366
Entity: Universitat Rovira i Virgili
Journal publication year: 2021
Publication Type: Journal Publications
Repositori URV