Plasma-Assisted Photocatalysis of CH₄ and CO₂ into Ethylene

Oxidative coupling of methane (OCM) using CO₂ as the oxidant is a potential advancement for methane conversion and greenhouse gases reduction. However, the reaction is usually limited by both high energy consumption and strict reaction condition. Here, we report, for the first time, photoinduced efficient ethylene (C₂H₄) and CO production by OCM over TiO₂-supported Ag nanoparticles at mild conditions. The success relies on a synergy coupling visible-light-induced strong surface plasma resonance (SPR) effect localized on Ag(0), ultraviolet-light-induced photoelectric effect on TiO₂, and the separated adsorption of CO₂ and CH₄ on TiO₂ and Ag. The yields of CO and C₂H₄ reach 1149 and 686 μmol·g^-1·h^-1, respectively, under simulated solar irradiation. The origination of carbon-based gas products from CO₂ and CH₄ is also certified by a ¹³C isotope-labeled experiment. This work presents a new and ideal route of photocatalytic OCM reaction for C₂H₄ and CO production by coupling both SPR and photoelectric effects.