Cost-effective and dynamic carbon dioxide conversion into methane using a CaTiO3@Ni-Pt catalyst in a photo-thermal hybrid system

This research focuses on the synergy of converting carbon dioxide (CO2) into methane (CH4) by simultaneously introducing light and heat as dynamic sources to activate the catalyst. A CaTiO3@Ni-Pt catalyst, loaded with 30.0 wt.% Ni and 1.0 wt.% Pt on a perovskite CaTiO3 support was introduced. The photo-thermal catalytic hybrid system has two features that distinguish it from other photo- or thermal-catalytic systems. First, unlike the CO2 thermal-methanation reaction where CO2 and H-2 react at a molar ratio of 1:4, 2.0 mol of H-2 was replaced with 2.0 mol H2O in the photo-thermal catalytic hybrid system compared to the thermal-methanation reaction requiring 4.0 mol of H-2. Second, by loading Ni and Pt, which are catalytic active species with excellent CO2 and H-2 adsorption abilities, the CO2 reduction (46.48%) was promoted and the CH4 selectivity (99.46%) in the product was increased compared to the photo-methanation reaction. The CaTiO3@Ni-Pt not only inhibited the recombination of the photo-generated charges, but also facilitated the adsorption of the reactants in the photo-thermal hybrid system. The quantum efficiency of the CaTiO3@Ni-Pt catalyst measured for the photo thermal hybrid system steadily increased to 180 degrees C. Nevertheless, this study implies that a photo-thermal hybrid system can be useful to photo-reducing CO2 by adding a small amount of heat. From a thermal reaction standpoint, a photo-thermal hybrid system can be used to reduce, the reaction temperature during CO2 thermal-methanation and to reduce the consumption of H-2 in half.