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- Title
Molecular oxygen enhances H<sub>2</sub>O<sub>2</sub> utilization for the photocatalytic conversion of methane to liquid-phase oxygenates.
- Authors
Sun, Xiao; Chen, Xuanye; Fu, Cong; Yu, Qingbo; Zheng, Xu-Sheng; Fang, Fei; Liu, Yuanxu; Zhu, Junfa; Zhang, Wenhua; Huang, Weixin
- Abstract
H2O2 is widely used as an oxidant for photocatalytic methane conversion to value-added chemicals over oxide-based photocatalysts under mild conditions, but suffers from low utilization efficiencies. Herein, we report that O2 is an efficient molecular additive to enhance the utilization efficiency of H2O2 by suppressing H2O2 adsorption on oxides and consequent photogenerated holes-mediated H2O2 dissociation into O2. In photocatalytic methane conversion over an anatase TiO2 nanocrystals predominantly enclosed by the {001} facets (denoted as TiO2{001})-C3N4 composite photocatalyst at room temperature and ambient pressure, O2 additive significantly enhances the utilization efficiency of H2O2 up to 93.3%, giving formic acid and liquid-phase oxygenates selectivities respectively of 69.8% and 97% and a formic acid yield of 486 μmolHCOOH·gcatalyst−1·h−1. Efficient charge separation within TiO2{001}-C3N4 heterojunctions, photogenerated holes-mediated activation of CH4 into ·CH3 radicals on TiO2{001} and photogenerated electrons-mediated activation of H2O2 into ·OOH radicals on C3N4, and preferential dissociative adsorption of methanol on TiO2{001} are responsible for the active and selective photocatalytic conversion of methane to formic acid over TiO2{001}-C3N4 composite photocatalyst. The oxidation of methane to formic acid or related oxygenates relies on efficient reaction with H2O2. Here, the authors report a TiO2-based catalyst to selectively form formic acid by using molecular O2 additives to avoid unwanted side reactions.
- Subjects
FORMIC acid; METHANE; OXYGEN; OXIDATION of formic acid
- Publication
Nature Communications, 2022, Vol 13, Issue 1, p1
- ISSN
2041-1723
- Publication type
Article
- DOI
10.1038/s41467-022-34563-4