Solar-promoted photo-thermal CH4 reforming with CO2 over Ni/CeO2 catalyst: Experimental and mechanism studies

Combining solar light and heat in dry reforming of methane (DRM) is a promising technology for reducing CO2 to a valuable syngas and increasing the utilization of solar light in the solar-to-fuel process. The reaction temperature is still high and the mechanism remains unclear in DRM. Clarifying the synergistic mechanism of solar light and heat is pivotal for industrial applications. To this end, a nanoscale Ni/CeO2 catalyst is prepared, and the synergistic effect of solar light and heat in DRM is experimentally investigated. The experimental results show that photo-thermochemistry leads to a 39.74% increase in relative conversion rate of CH4 compared to thermochemistry, while the reaction temperature is reduced by 45 °C. The syngas production rate and the selectivity of DRM are improved by solar light. The in-situ infrared study indicates that solar light enhances the dissociation process of CH4 and the production of HCOO⁎ on the surface of the Ni/CeO2 catalyst. The light response in the catalyst and microscopic enhancement of intermediate products are responsible for the increased DRM performance under photo-thermochemical conditions. These findings contribute to the understanding of the synergistic effects of solar light and heat, and guide the conversion of CO2 into fuel with the aid of solar energy.