Precisely Modulating the Interfacial Oxygen Radicals for Selective Photocatalytic Methane Partial Oxidation to Methanol.

Selective photocatalytic partial oxidation of methane (CH4) under ambient conditions offers a sustainable route for direct methanol (CH3OH) production while reducing greenhouse gases. However, achieving both high yield and selectivity remains challenging due to the uncontrolled generation of reactive oxygen species (ROS), particularly hydroxyl radicals (•OH), which readily overoxidize CH3OH. Here, we report a PdNi alloy cocatalyst supported on TiO2 that enables fine-tuning of interfacial ROS dynamics via electronic and structural modulation. Mechanistic studies reveal that the PdNi interface couples moderate kinetic barriers for *O protonation with thermodynamic enhancement of *OH adsorption via d-band center modulation. This cooperative effect suppresses the transition of O2 into reactive •OH species, thereby mitigating CH3OH overoxidation. As a result, the optimized PdNi0.49/TiO2 photocatalyst achieves a CH3OH yield of 9557.4 µmol g-1 h-1 with 87.5% selectivity using molecular O2 as the sole oxidant. Beyond regulating ROS dynamics, Ni incorporation also optimizes the desorption behavior of CH3OH, further contributing to the high selectivity of the target product. This work establishes a rational interfacial design strategy for steering photocatalytic oxidation pathways and advancing selective methane conversion technologies.