Selective Photocatalytic Aerobic Oxidation of Methane to Methyl Hydroperoxide by ZnO-Loaded Single-Atomic Ruthenium Oxide Catalyst
Hantao Gong, Li Zhang, Caihao Deng, Mingjie Liu, X.L. Liu, Yongkang Huang, Kai Zhou, Peipei He, Jing Li, Yiwen Yang, Liang Wang, Qiwei Yang, Zongbi Bao, Qilong Ren, Ting Tan, Siyu Yao, Zhiguo Zhang
Abstract
Photooxidation of CH 4 to value-added chemicals with high selectivity offers a promising pathway to drive the rational utilization of natural gas resources with renewable energy under mild conditions. However, owing to the poor chemoselectivity of reactive oxygen radical formation and consecutive side reactions of primary products, the synthesis of peroxide directly from CH 4 oxidation remains challenging. Here, we report single-atom ruthenium oxide-doped ZnO as a highly selective photocatalyst for the aerobic oxidation of CH 4 to CH 3 OOH. Under optimal conditions, the CH 3 OOH formation rate over Ru 1 O x /ZnO reaches 321 μmol g cat –1 h –1 with a high selectivity of 90.9% under simulated solar irradiation. Mechanistic studies reveal that the selective generation of •OOH radicals via oxygen reduction and the ability to prevent secondary side reactions of CH 3 OOH are the main advantages of Ru 1 O x /ZnO, accounting for the remarkable selectivity of CH 3 OOH from CH 4 . The single-atom Ru oxide/ZnO catalyst also exhibits remarkable chemoselectivity to alkyl hydroperoxide in the photocatalytic oxidation of low paraffins, which provides a solution to prepare value-added peroxide from a single-step oxidation of hydrocarbon substrates.