Highly active Ni/Al 2 O 3 catalyst for CO 2 methanation by the decomposition of Ni-MOF@Al 2 O 3 precursor via cold plasma

In this work, a novel Ni/Al 2 O 3 -P catalyst for CO 2 methanation was prepared via an oxygen plasma decomposition of the Ni-MOF@Al 2 O 3 core–shell precursor. The obtained catalyst showed a higher Ni dispersion (26.5%) and contained less NiAl 2 O 4 spinel when compared with the Ni/Al 2 O 3 prepared by the traditional method. The Ni/Al 2 O 3 -P catalyst showed significantly enhanced efficiency toward CO 2 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 (STY CH4 ) of the Ni/Al 2 O 3 -P catalyst was as high as 21103.6 mg∙g Ni -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∙g Ni -1 ∙h −1 ) with a similar nickel loading under similar reaction conditions. Moreover, Density Functional Theory (DFT) studies together with the CO 2 -TPD results revealed that both nickel surface and Ni-Al 2 O 3 interface could activate CO 2, while the NiAl 2 O 4 surface could not.