In this work, a novel Ni/Al2O3-P catalyst for CO2 methanation was prepared via an oxygen plasma decomposition of the Ni-MOF@Al2O3 core–shell precursor. The obtained catalyst showed a higher Ni dispersion (26.5%) and contained less NiAl2O4 spinel when compared with the Ni/Al2O3 prepared by the traditional method. The Ni/Al2O3-P catalyst showed significantly enhanced efficiency toward CO2 methanation as compared with those catalysts with a similar nickel loading but are prepared using the traditional method. For example, the space time yield of methane (STYCH4) of the Ni/Al2O3-P catalyst was as high as 21103.6 mg?gNi-1?h- 1 at 400 ?C and GHSV as 12000 ml?g- 1?h- 1, which is 3.4 times higher than that of the reported catalyst (6190.5 mg?gNi-1?h- 1) with a similar nickel loading under similar reaction conditions. Moreover, Density Functional Theory (DFT) studies together with the CO2-TPD results revealed that both nickel surface and Ni-Al2O3 interface could activate CO2, while the NiAl2O4 surface could not.