Visible‐Light Photochemical Reduction of CO2 to CO Coupled to Hydrocarbon Dehydrogenation. (12th February 2020)

• Record Type: Journal Article
• Authors: Yu, Huijun; Haviv, Eynat; Neumann, Ronny
• Is Part Of: Angewandte Chemie. Volume 132:Number 15(2020)
• Page Start: 6278
• Page End: 6282
• Publication Date: 2020-02-12
• Subjects: Kohlenstoffnitrid -- CO2-Reduktion -- Kohlenwasserstoffdehydrierung -- Polyoxometallate; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201915733
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: Research on the photochemical reduction of CO2, initiated already 40 years ago, has with few exceptions been performed by using amines as sacrificial reductants. Hydrocarbons are high‐volume chemicals whose dehydrogenation is of interest, so the coupling of a CO2 photoreduction to a hydrocarbon‐photodehydrogenation reaction seems a worthwhile concept to explore. A three‐component construct was prepared including graphitic carbon nitride (g‐CN) as a visible‐light photoactive semiconductor, a polyoxometalate (POM) that functions as an electron acceptor to improve hole–electron charge separation, and an electron donor to a rhenium‐based CO2 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 CO2 to CO. The construct was characterized by zeta potential, IR spectroscopy, thermogravimetry, scanning electron microscopy (SEM) and energy dispersive X‐ray spectroscopy (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. Abstract : Die Kopplung von CO2 ‐Photoreduktion und Photodehydrierung von Cyclohexen gelang mithilfe eines Drei‐Komponenten‐Konstrukts bestehend aus graphitischem Kohlenstoffnitrid als photoaktiver Halbleiter und einem Polyoxometallat, das als Elektronenakzeptor die Loch‐Elektron‐Trennung verstärkt und außerdem als Elektronendonor für einen CO2 ‐Reduktionskatalysator auf Rheniumbasis dient.