The promotion effects of Ni on the properties of Cr/Al catalysts for propane dehydrogenation reaction

•Promotion effects of Ni on Cr/Al catalysts are experimental presented.•Propane conversion of 2.5Cr-Ni/Al is 20% higher than that of 2.5Cr/Al catalyst.•The interactions between Ni and Cr species of Cr-Ni/Al catalysts are discussed.•The doped Ni promotes the formation of oligomeric chromium species.•The doped Ni affects the valence of surface Cr species on supports.

The Cr/Al and Cr-Ni/Al catalysts were prepared and contrastively studied for propane dehydrogenation reaction. The results verify that the catalytic performances of Cr-Ni/Al catalysts are evidently higher than those of Cr/Al catalysts due to the impregnation of Ni species. Especially, the propane conversion of 2.5Cr-Ni/Al catalyst attains ∼43%; while it is only ∼24% for 2.5Cr/Al catalyst without Ni species. The promotion effects of Ni on the properties of Cr/Al catalysts for propane dehydrogenation reaction are elaborated upon several state-of-art physico-chemical characterizations including UV–vis, XPS, H2-TPR, NH3-TPD and so on. These characterizations fully confirm the existence of interaction between Ni and Cr species on the surfaces of Cr-Ni/Al catalysts. In addition, the introduction of Ni promotes the formation of oligomeric chromium species and affects the valence of surface Cr species on supports, which would have crucial influences on the improvement of catalytic activity for propane dehydrogenation reaction.

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