Effective thermocatalytic carbon dioxide methanation on Ca-inserted NiTiO₃ perovskite

The thermocatalytic methanation of carbon dioxide has been established to be more efficient than photocatalytic methanation, and the throughput of the former is also incomparably high. Because the products can be selectively controlled by adjusting the reaction temperature or the type of catalyst, thermocatalytic methanation is extremely dependable for simultaneously resolving environmental and energy problems. Herein, to improve CO₂ adsorption, the nickel component of NiTiO₃ perovskites was partially substituted with calcium ions. The Ca insertion generated oxygen vacancies around NiO in Ca-NiTiO₃ with an improved catalytic performance for methane production. The CO₂ conversion, CH₄ yield, and selectivity for CH₄ achieved during CO₂ methanation for 10 day on 5.0 mol.% Ca-NiTiO₃/γ-Al₂O₃ was 84.73, 78.84, and 99.95%, respectively. The reaction conditions were optimized (GHSV = 2000 h⁻¹, reaction temperature = 350 °C, and CO₂/H₂ feed gas ratio = 1/4) and a high catalytic performance was maintained for 10 days without catalyst deterioration. Overall, the adequate self-induced oxygen defects in the perovskite framework that were formed by Ca insertion increased the H₂, CO, and CO₂ adsorption; further, it ultimately improved CO₂ methanation.