Platinum-Catalysed Selective Aerobic Oxidation of Methane to Formaldehyde in the Presence of Liquid Water.

Autor: Mahlaba SVL; Catalysis Institute, Department of Chemical Engineering, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa., Hytoolakhan Lal Mahomed N; Catalysis Institute, Department of Chemical Engineering, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa., Govender A; Group Technology, Sasol South Africa (Pty) Ltd., P.O. Box 1, Sasolburg, 1947, South Africa., Guo J; Catalysis Institute, Department of Chemical Engineering, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa., Leteba GM; Catalysis Institute, Department of Chemical Engineering, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa., Cilliers PL; Catalysis Institute, Department of Chemical Engineering, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa., van Steen E; Catalysis Institute, Department of Chemical Engineering, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa.
Jazyk: angličtina
Zdroj: Angewandte Chemie (International ed. in English) [Angew Chem Int Ed Engl] 2022 Sep 19; Vol. 61 (38), pp. e202206841. Date of Electronic Publication: 2022 Aug 16.
DOI: 10.1002/anie.202206841
Abstrakt: The aerobic, selective oxidation of methane to C 1 -oxygenates remains a challenge, due to the more facile, consecutive oxidation of formed products to CO 2 . Here, we report on the aerobic selective oxidation of methane under continuous flow conditions, over platinum-based catalysts yielding formaldehyde with a high selectivity (reaching 90 % for Pt/TiO 2 and 65 % over Pt/Al 2 O 3 ) upon co-feeding water. The presence of liquid water under reaction conditions increases the activity strongly attaining a methane conversion of 1-3 % over Pt/TiO 2 . Density-functional theory (DFT) calculations show that the preferential formation of formaldehyde is linked to the stability of the di-σ-hydroxy-methoxy species on platinum, the preferred carbon-containing species on Pt(111) at a high chemical potential of water. Our findings provide novel insights into the reaction pathway for the Pt-catalysed, aerobic selective oxidation of CH 4 .
(© 2022 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)
Databáze: MEDLINE
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