Selective Oxidation of Methane to Formaldehyde over a Silica-Supported Cobalt Single-Atom Catalyst

作者：Junya Ohyama, Daiki Abe, Airi Hirayama, Hiroki Iwai, Yuka Tsuchimura, Kazuki Sakamoto, Momoka Irikura, Yuri Nakamura, Hiroshi Yoshida, Masato Machida, Shun Nishimura, Tomokazu Yamamoto, Syo Matsumura, Keisuke Takahashi · 发表于：The Journal of Physical Chemistry C · 年份：2022 · DOI：10.1021/acs.jpcc.1c08739 · 被引用次数：40 · 研究领域：Catalytic Processes in Materials Science、Catalysis and Oxidation Reactions、Catalysts for Methane Reforming

Catalytic oxidation of methane to formaldehyde and methanol has attracted attention because of its advantage in energy efficiency over the conventional multistep reaction process involving endothermic steam reforming of CH 4; however, it is challenging to selectively obtain the partial oxidation products in the direct oxidation of CH 4 . In the present study, Co/SiO 2 with various Co loadings was tested for the CH 4 /O 2 /H 2 O gas flow reaction. As a result, Co/SiO 2 with a low loading of ≤0.1 wt % showed high selectivity for the partial oxidation reaction and mainly produced HCHO, while Co/SiO 2 with high Co loadings proceeded to complete oxidation. Structural analysis using X-ray absorption fine-structure spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and scanning transmission electron microscopy suggested that single Co atoms generated at low Co loadings were effective in the selective oxidation of CH 4 to HCHO, while Co 3 O 4 nanoparticles generated at high Co loadings promoted the complete oxidation.