Ni–CaZrO₃ with perovskite phase loaded on ZrO₂ for CO₂ methanation

CO₂ methanation has emerged as a promising strategy for the greenhouse gas CO₂ utilization and storage of hydrogen. However, achieving low temperature activity and high temperature stability remains challenging due to the sintering of Ni-based catalysts. To address these limitations, this study introduces a Ni–CaZrO₃ catalyst featuring a perovskite phase supported on ZrO₂, prepared via citrate complexation and impregnation methods. In this approach, a perovskite-type oxide (PTO) of CaZrO₃ forms through a solid reaction on the surface of ZrO₂ with impregnated CaO. The formation of CaZrO₃ on Ni/ZrO₂ restrains the ZrO₂ support aggregation and reduces the particle size of Ni nanoparticles (NPs), thereby enhancing the activity for CO₂ methanation. The interaction between Ni–CaZrO₃, and ZrO₂ effectively confines the Ni NPs and CaZrO₃, enhancing the sintering resistance of Ni–CaZrO₃. This leads to excellent stability of the resulting catalyst for CO₂ methanation. The Ni–CaZrO₃/ZrO₂ catalyst achieves 85% CO₂ conversion and maintains 100% methane selectivity at 300 °C, demonstrating the prolonged stability over 100 h at 550 °C. Notably, the loading of CaZrO₃ in a perovskite phase on ZrO₂ via solid surface reaction represents an interesting and valuable route, which could be extended to loading other PTOs for industrial applications.