▎ 摘　　要

Direct conversion of CH4 to CH3OH in an economical and environmentally friendly way is a highly desirable process, and the development of easily accessible activity descriptors can promote the design of high-performance catalysts for the achievement of this on the gas-phase selective oxidation of CH4 to CH3OH with oxidants N2O and O-2 on the transition-metal (TM)-atom-embedded N-doped graphene (TM-N-4/C) single-atom catalysts (SACs) were performed to shed light on the detailed reaction mechanism and the scaling relationship for the catalytic activity. Computational screening reveals that the adsorption energy of O (?E-O) has strong correlation with the reactivity toward the direct conversion of CH4 to CH3OH with the oxidant N2O on a wide range of TM-N-4/C catalysts. More instructively, the presence of one water molecule in the active domain may facilitate the selective oxidation of methane to methanol remarkably, suggesting that the noncovalent interaction as the catalyst cofactor may judiciously manipulate the catalytic activity. In addition, ?E-O is also a promising catalytic descriptor for the selective oxidation of CH(4 )with the atmospheric O-2 as an oxidant. Among these TM-N-4/C SACs, Fe-N-4/C is identified as an ideal material for the direct conversion of CH4 to CH3OH. The present results and established scaling relationships may be used for predicting graphene-based SACs for the catalytic oxidation of CH4 to CH3OH more efficiently under mild conditions.