The Effect of Different Promoters (La2O3, CeO2, and ZrO2) on the Catalytic Activity of the Modified Vermiculite-Based Bimetallic NiCu/EXVTM-SiO2 Catalyst in Methane Dry Reforming

An X-NiCu/EXVTM-SiO 2 (X = La, Ce, and Zr) catalyst was successfully prepared by using modified vermiculite as a support by the impregnation method. This experiment investigated the effects of La 2 O 3 , CeO 2 , and ZrO 2 promoters on the activity of the NiCu/EXVTM-SiO 2 catalyst. The study found that the addition of three different metal oxides did not improve the activity of the NiCu/EXVTM-SiO 2 catalyst. On the contrary, some Ni active sites were covered by the promoter, which reduced the number of active sites, resulting in its catalytic activity lower than NiCu/EXVTM-SiO 2 . In addition, the promoted catalysts that were repeatedly calcined two times can significantly reduce the textural property as well as active sites of the catalyst, resulting in the lower activity. However, in X-NiCu/EXVTM-SiO 2 , Ce-NiCu/EXVTM-SiO 2 showed relatively high initial catalytic activity, with the initial conversion rate of CH 4 reaching 60.1% and the initial conversion rate of CO 2 reaching 89.1%. This is mainly because the catalyst has a stronger basic site on the surface to facilitate the adsorption of CO 2 molecules, and the smaller metal particle size is also conducive to the cleavage of C–H bonds.