CO2 laser promoted oxygen vacancy-active oxygen cycle in DRM on Ni/CeO2

[Display omitted] •DRM was driven by a mid-infrared CO2 laser at mild catalyst layer temperatures.•Better low-temp reactivity obtained under laser treatment than in thermocatalysis.•CO2 laser generated more active sites and oxygen vacancies in catalyst system.•CO2 laser enhanced the key oxygen vacancy-active oxygen cycle in DRM. The global climate change has led to great interest in dry reforming of methane (DRM) to produce syngas from two greenhouse gases, CO2 and CH4. In order to investigate the reaction characteristics and mechanism under mid-infrared light irradiation, a 10.6 µm CO2 laser was introduced as an energy source to perform the complete DRM process on Ni/CeO2 at mild temperature. This scheme was compared with the traditional thermal mode under similar catalyst layer temperature. The laser-driven mode yielded significantly better performance around the DRM light-off temperature of the catalytic system, due to several-fold higher reactant conversion and product selectivity than in thermocatalytic mode. Based on a series of characterizations, the CO2 laser not only generated more than twice the number of oxygen vacancies than that in thermal mode at pre-reduction stage, but also enhanced the dissociative adsorption of CO2 and the circulation of oxygen vacancy-reactive oxygen at methane reforming stage. This study provides insight into the mechanism of CeO2 materials for DRM under mid-infrared illumination.