Efficient and Selective Photocatalytic Oxidation of CH₄ over Fe Single-Atom-Incorporated MOFs under Visible Light

Photocatalytic CH4 oxidation to liquid products under room temperature is a promising way for maximizing the value of CH4. However, the selective oxidation of CH4 is a big challenge due to the high dissociation energy of CH4 and the high reactivity of liquid products. Here, we report the Fe single-atom-incorporated metal-organic framework (Fe@PCN-222) as an effective and selective photocatalyst for photocatalytic oxidation of CH4 to liquid oxygenates (CH3OH and HCHO) under visible light at room temperature. Fe@PCN-222 exhibits a liquid oxygenate yield of 19.0 mu mol in 2 h and a selectivity of 88.4% in the presence of 400 mu mol H2O2 and 2 MPa CH4, far exceeding that of the bare PCN-222 photocatalyst. The Fe single-atoms in PCN-222 not only promote the photogenerated electron transfer but also facilitate the activation of H2O2 to produce active OH, which synergistically results in a substantial improvement of selectivity and activity of liquid oxygenate production.