Mahlaba Sinqobile V L, Hytoolakhan Lal Mahomed Nasseela, Govender Alisa, Guo Junfeng, Leteba Gerard M, Cilliers Pierre L, van Steen Eric
Catalysis Institute, Department of Chemical Engineering, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa.
Group Technology, Sasol South Africa (Pty) Ltd., P.O. Box 1, Sasolburg, 1947, South Africa.
Angew Chem Int Ed Engl. 2022 Sep 19;61(38):e202206841. doi: 10.1002/anie.202206841. Epub 2022 Aug 16.
The aerobic, selective oxidation of methane to C -oxygenates remains a challenge, due to the more facile, consecutive oxidation of formed products to CO . 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 and 65 % over Pt/Al O ) 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 . 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 .
将甲烷进行有氧选择性氧化生成含碳含氧化合物仍然是一项挑战，因为生成的产物更容易连续氧化为二氧化碳。在此，我们报道了在连续流动条件下，以铂基催化剂对甲烷进行有氧选择性氧化，在共进料水的情况下，可高选择性地生成甲醛（Pt/TiO₂的选择性达到90%，Pt/Al₂O₃的选择性超过65%）。反应条件下液态水的存在极大地提高了活性，在Pt/TiO₂上甲烷转化率达到1%-3%。密度泛函理论（DFT）计算表明，甲醛的优先形成与二σ-羟基甲氧基物种在铂上的稳定性有关，在高水化学势下，该物种是Pt(111)上优选的含碳物种。我们的研究结果为铂催化甲烷有氧选择性氧化的反应途径提供了新的见解。
