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

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 PdNi_0.49/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.