Synergetic effect for highly efficient light-driven CO2 reduction by CH4 on Co/Mg-CoAl2O4 promoted by a photoactivation

Abstract

The utilization of photothermocatalytic dry reforming of methane is shown to be an up-and-coming technology. However, reaching high fuel productivity at a comparatively low light intensity and effectively suppressing the side reactions of coking in the DRM process are still two tough difficulties. Under focused UV–vis–IR irradiation at a relatively low light intensity of 80.5 kW m−2, a nanostructure of Co/Mg-CoAl2O4 possesses excellent photothermocatalytic activity and a light-to-fuel efficiency of 34.2 % and a low carbon deposition rate compared to its reference catalyst without Mg2+ doping (Co/CoAl2O4). The improved photothermocatalytic activity and coking resistance of Co/Mg-CoAl2O4 mainly comes from the synergetic effect, including Mg2+ doping, the active lattice oxygen in CoAl2O4 also participating in the oxidation of carbon species, and strong light absorption properties of the Mg-CoAl2O4. The photoactivation promotes DRM on Co nanoparticles while significantly facilitates the C* oxidation by strongly adsorbed CO2 on doped Mg2+.