CO2 methanation activity of Ni-doped perovskites

•Ni-doped CaTiO3 (CTO) perovskites show remarkable stable activity during CO2 methanation.•These catalysts stabilize smaller NiO crystallites compared to traditional Ni supported catalysts.•Catalysts with NiO crystallite under 10 nm show highest CO2 conversion and 100% CH4 selectivity.•Oxygen vacancies on Ni-doped CTO favors CO2 adsorption and stable conversion to CH4. Nickel-doped CaTiO3 (Ni@CTO) perovskites were prepared by sol–gel synthesis and compared to traditional CTO-supported Ni catalysts during the CO2 methanation reaction. All the prepared materials were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, temperature programmed reduction and CO2 temperature programmed desorption. Both types of catalysts showed activity in the CO2 methanation, being the most active those that showed a particle size less than 10 nm. These samples showed a CO2 conversion around 80%, with 100% selectivity to CH4. In addition, the activity of doped catalyst began at lower temperature, possibly due to the enhanced CO2 adsorption sites related to the formation of oxygen vacancies in the perovskite after nickel doping, and to its higher specific surface area. In addition, the 10Ni@CTO catalyst shows a high stability at 40 h of reaction, with only a 1% decrease in CO2 conversion, while the selectivity remained constant. The results showed that Ni@CTO doped perovskites are promising catalysts for methanation.