Thermally Regulated Methanol Selectivity in Photo-Thermo Methane Oxidation Through Interfacial Methyl Transfer

The direct oxidation of methane to methanol has long been pursued as a low-carbon alternative to syngas-based production routes. However, its practical implementation remains constrained by low methanol selectivity in thermocatalysis and limited productivity in photocatalysis. Although temperature is intrinsic to catalytic systems, its role in photocatalysis has largely been regarded as secondary and predominantly kinetic. Here, we demonstrate that mild thermal input serves as an effective mechanistic lever to regulate reaction selectivity in a photo-thermo cascade catalytic system based on Au nanoparticle-decorated ZnO. This system achieves a methanol production rate of ∼800 µmol h^-1 with 86% selectivity at 150°C, corresponding to an approximately tenfold increase in productivity and a 150% increase in selectivity relative to photocatalysis alone. While light irradiation enables methane C-H activation, thermal excitation reshapes the reaction network by promoting interfacial transfer of surface-bound methyl species from oxide sites toward Au domains, thereby redirecting reaction flux toward methanol formation. Mechanistic studies support thermally promoted interfacial methyl transfer as a key contributor to the temperature-regulated selectivity. This thermally tunable selectivity is further demonstrated across a series of Au-loaded metal-oxide semiconductors, highlighting interfacial pathway regulation as a general design principle for efficient and selective methane-to-methanol conversion.