Ag–Co Dual Sites-Decorated TiO2 Enabling Accelerated Electron Transfer for Selective Photocatalytic Oxidative Coupling of Methane

Photocatalytic oxidative coupling of methane (OCM) offers a sustainable pathway for direct conversion of methane into value-added hydrocarbons, yet faces persistent challenges in balancing efficient methane activation with suppression of overoxidation. Here, we present a TiO2-based photocatalyst decorated with highly dispersed Ag–Co dual sites that achieves superior performance in continuous-flow OCM. The optimized AgCo–TiO2 system demonstrates a remarkable C2 hydrocarbon production rate of 1.7 mmol g–1 h–1 with 91% selectivity while maintaining stable operation for over 30 h. In situ spectroscopic analyses indicate that the introduced Co species induce mobile-charge imbalances, driving the directional transfer of photogenerated electrons and effectively suppressing electron–hole recombination. Coupled with Ag serving as a catalytic center, these effects synergistically enhance O2 activation, C–H bond cleavage, and selective C–C coupling, thereby contributing to the superior catalytic performance. This work provides valuable mechanistic insights into the photocatalytic OCM process, highlighting the pivotal role of precisely engineered charge transfer pathways in enabling efficient methane-to-C2 conversion.