An X-NiCu/EXVTM-SiO2 (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 La2O3, CeO2, and ZrO2 promoters on the activity of the NiCu/EXVTM-SiO2 catalyst.
The study found that the addition of three different metal oxides
did not improve the activity of the NiCu/EXVTM-SiO2 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-SiO2. 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-SiO2, Ce-NiCu/EXVTM-SiO2 showed relatively high initial
catalytic activity, with the initial conversion rate of CH4 reaching 60.1% and the initial conversion rate of CO2 reaching 89.1%. This is mainly because the catalyst has a stronger
basic site on the surface to facilitate the adsorption of CO2 molecules, and the smaller metal particle size is also conducive
to the cleavage of C–H bonds.
Macroporous nanocast perovskites, LaFe1−xNixO3 (x = 0.3, 0.5, and 0.7), were synthesized by using a nanocasting technique with SBA-15 as a template and applied to methane dry reforming (MDR). The prepared catalysts were characterized by X-ray diffraction, transmission electron microscopy, specific-surface-area analysis, hydrogen temperature-programmed reduction, and thermogravimetric analysis. LaFe1−xNixO3 revealed a large specific surface area, which could enhance its catalytic activity. The catalysts were reduced to Ni/LaFeO3-La2O3 in the MDR reaction. The alkaline additive, La2O3, and perovskite oxide, LaFeO3, strongly interacted with the active component to reduce the surface energy of metal particles and prevent aggregation of active Ni. The results showed that LaFe0.5Ni0.5O3 and LaFe0.3Ni0.7O3 perform better than LaFe0.7Ni0.3O3. More importantly, LaFe0.5Ni0.5O3 had a very long lifetime (>80 h) in the MDR reaction. The LaFe0.5Ni0.5O3 catalyst showed excellent stability in the MDR reaction and has potential use in industrial applications.
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