Research progress in single-atom catalysts for the selective oxidation of methane

Single-atom catalysts exhibit significant advantages in terms of exceptional atomic utilization and tunable coordination environments. The unique atomic structure of the material enhances the reaction rate of methane under mild conditions by inducing electrostatic polarization in C–H bonds, leading to a significant reduction in activation energy. Additionally, it stabilizes intermediates and prevents excessive oxidation of reaction products. In this review, we critically summariz the recent advancements in single-atom catalyst research for the direct selective oxidation of methane to C1–C2 oxygenates under low temperature-liquid-phase conditions. In particular, the design and preparation methods of atomically dispersed active site catalysts on different supports (carbon-based materials, molecular sieves, metal oxides, metal-organic frameworks), the reaction mechanism of activated methane, and the structure-activity relationship between the support and the catalytic performance were discussed. Finally, the advantages and challenges of various atomic-level-dispersed catalysts for the selective oxidation of methane are briefly discussed, and the development of single-atom catalysts is prospected.