Interfacial charge‐regulated peroxide pathway enables visible‐light‐driven oxidative coupling of methane to ethane

Abstract

Controlling oxygen activation while suppressing overoxidation remains a central challenge in photocatalytic oxidative coupling of methane (OCM) under mild conditions. Herein, we report an interfacial charge‐regulated strategy for selective visible‐light‐driven methane coupling to ethane over an In ₂ O ₃ ‐synergized Au/TiO _2−x photocatalyst. The introduction of In ₂ O ₃ establishes a built‐in electric field at the In ₂ O ₃ /Au/TiO _2−x heterointerface, enhancing charge separation and driving directional photogenerated electron migration along the pathway of In ₂ O ₃  → TiO _2−x  → Au and resulting in electron‐enriched Au sites under irradiation. These sites fundamentally alter the oxygen activation pathway by promoting the formation of mild peroxide species (O ₂ ²⁻ ) while suppressing highly oxidative oxygen species. The resulting O ₂ ²⁻ species activate CH ₄ to form *CH ₃ intermediates, which undergo selective C–C coupling on Au. As a result, the catalyst achieves an ethane formation rate of 304.6 ± 7.6 μmol·g ⁻¹ ·h ⁻¹ with 99.4% selectivity under visible‐light irradiation. The rate increases to 32.9 ± 0.5 mmol·g ⁻¹ ·h ⁻¹ under full‐spectrum irradiation.