Effect of Rutile Content on the Catalytic Performance of Ru/TiO₂ Catalyst for Low-Temperature CO₂ Methanation

Abstract

Hydrogenation of carbon dioxide (CO2) to methane (CH4) bears the potential not only to alleviate excessive emission of CO2 but to produce clean energy for direct use. However, due to the high temperature required for the activation of CO2, it is necessary to develop a catalyst with high activity and high CH4 selectivity at low reaction temperature for CO2 methanation. In this study, we synthesized titanium dioxide (TiO2) supports with different rutile contents by calcination and investigated the relationship between the rutile content of TiO2 supports in Ru/TiO2 catalysts and their performance for low-temperature CO2 methanation. The characterization results indicated that Ru species grew preferentially on the rutile phase of the support TiO2, and the interaction between Ru species and TiO2 became stronger with increasing rutile content. In addition, the concentration of oxygen vacancies on the support, which would provide more adsorption sites for CO2, increased with the decreasing rutile content. The best reactivity was achieved with a rutile content between 15% and 30%. This work included a thorough investigation on the effect of rutile content on the performance of low-temperature CO2 methanation and provided guidance for the preparation of Ru/TiO2 catalyst with high activity.