Effective thermocatalytic carbon dioxide methanation on Ca-inserted NiTiO3 perovskite

[Display omitted] •Enhanced CO2 adsorption on NiTiO3 by Ca insertion.•Improvement of the catalytic performance into CH4 production.•Proper oxygen defects self-inducing in the perovskite framework.•High catalytic performance maintained for 10 days without catalytic deterioration. 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.