Pivotal Role of Holes in Photocatalytic CO 2 Reduction on TiO 2 .

Autor: Moustakas NG; Department of Heterogeneous Photocatalysis, Leibniz-Institute for Catalysis (LIKAT), Albert-Einstein-Str. 29a, 18059, Rostock, Germany., Lorenz F; Department of Heterogeneous Photocatalysis, Leibniz-Institute for Catalysis (LIKAT), Albert-Einstein-Str. 29a, 18059, Rostock, Germany., Dilla M; Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470, Mülheim an der Ruhr, Germany., Peppel T; Department of Heterogeneous Photocatalysis, Leibniz-Institute for Catalysis (LIKAT), Albert-Einstein-Str. 29a, 18059, Rostock, Germany., Strunk J; Department of Heterogeneous Photocatalysis, Leibniz-Institute for Catalysis (LIKAT), Albert-Einstein-Str. 29a, 18059, Rostock, Germany.
Jazyk: angličtina
Zdroj: Chemistry (Weinheim an der Bergstrasse, Germany) [Chemistry] 2021 Dec 06; Vol. 27 (68), pp. 17213-17219. Date of Electronic Publication: 2021 Nov 24.
DOI: 10.1002/chem.202103070
Abstrakt: Evidence is provided that in a gas-solid photocatalytic reaction the removal of photogenerated holes from a titania (TiO 2 ) photocatalyst is always detrimental for photocatalytic CO 2 reduction. The coupling of the reaction to a sacrificial oxidation reaction hinders or entirely prohibits the formation of CH 4 as a reduction product. This agrees with earlier work in which the detrimental effect of oxygen-evolving cocatalysts was demonstrated. Photocatalytic alcohol oxidation or even overall water splitting proceeds in these reaction systems, but carbon-containing products from CO 2 reduction are no longer observed. H 2 addition is also detrimental, either because it scavenges holes or because it is not an efficient proton donor on TiO 2 . The results are discussed in light of previously suggested reaction mechanisms for photocatalytic CO 2 reduction. The formation of CH 4 from CO 2 is likely not a linear sequence of reduction steps but includes oxidative elementary steps. Furthermore, new hypotheses on the origin of the required protons are suggested.
(© 2021 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)
Databáze: MEDLINE
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