Synergetic effect for highly efficient light-driven CO2 reduction by CH4 on Co/Mg-CoAl2O4 promoted by a photoactivation
Zhengyan Cui, Qianqian Hu, Yuanzhi Li, Jichun Wu, Xiaocui Yu, Huamin Cao, Lei Ji, Mengqi Zhong, Dongzhi Chen
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-CoAl 2 O 4 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 Mg 2+ doping (Co/CoAl 2 O 4 ). The improved photothermocatalytic activity and coking resistance of Co/Mg-CoAl 2 O 4 mainly comes from the synergetic effect, including Mg 2+ doping, the active lattice oxygen in CoAl 2 O 4 also participating in the oxidation of carbon species, and strong light absorption properties of the Mg-CoAl 2 O 4 . The photoactivation promotes DRM on Co nanoparticles while significantly facilitates the C* oxidation by strongly adsorbed CO 2 on doped Mg 2+ .