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.