Abstract
Research on the photochemical reduction of CO 2 , initiated already 40 years ago, has with few exceptions been carried out using amines as sacrificial reductants. Hydrocarbons are high volume chemicals whose dehydrogenation is of interest, so the coupling of a CO 2 photoreduction to a hydrocarbon photo-dehydrogenation reaction seems a worthwhile concept to explore. A 3-component construct was prepared including graphitic carbon nitride (g-CN) as a visible light photoactive semiconductor; a polyoxometalate that functions as an electron acceptor to improve hole-electron charge separation and an electron donor to a rhenium-based CO 2 reduction catalyst. Upon photoactivation of g-CN, a cascade is initiated by dehydrogenation of hydrocarbons coupled to the reduction of the polyoxometalate. Visible light photoexcitation of the reduced polyoxometalate enables electron transfer to the rhenium-based catalyst active for the selective reduction of CO 2 to CO. The construct was characterized by zeta potential, IR, thermogravimetry and SEM/EDS. An experimental Z-scheme diagram is presented based on electrochemical measurements and UV-vis spectroscopy. The conceptual advance should promote study into more active systems.
Citation
ID:
81577
Ref Key:
neumann2020visibleangewandte