Ni/Al2O3-ZrO2 catalyst for CO2 methanation: The role of γ-(Al, Zr)2O3 formation

CO2 methanation could offer significant energy and environment benefits if efficient catalyst is developed. Ni-based catalyst is the most promising catalyst for this reaction. Herein, a series of ZrO2 doped Ni/Al2O3 catalysts were fabricated by a co-precipitation method, and their reactivities with respect to the CO2 methanation were evaluated. Catalytic activities of the ZrO2-doped Ni/Al2O3 catalysts for CO2 methanation are superior to the undoped one. Characterization results suggest that γ-(Al, Zr)2O3 solid solution is formed after the introduction of ZrO2, which results in weakening the NiO-Al2O3 interaction and inhibits the formation of spinel NiAl2O4. After activated by hydrogen reduction, those ZrO2-doped NiO/Al2O3 catalysts show smaller Ni nanoparticles sizes, and the one doped with 16 wt% ZrO2 (Ni/AZ16) possesses the smallest sizes of Ni nanoparticles and shows the highest reactivity in the CO2 methanation.