Promoted Effect of Zinc and Sulfur on the Structural and Catalytic Properties of Bimetallic Nickel–Zinc Catalysts for the Dehydrogenation of Propane.

Autor: Tahier, Tayyibah, Mohiuddin, Ebrahim, Botes, Alicia, Frazenburg, Madelaine, Botha, Subelia, Mdleleni, Masikana M.
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Zdroj: Catalysis Letters; Aug2023, Vol. 153 Issue 8, p2527-2542, 16p
Abstrakt: Propane dehydrogenation catalysts, containing Ni and Zn were synthesised with the following wt% (13:0, 11:2, 9:4, 6.5:6.5, 4:9, 2:11 and 0:13) ratios. Structural and textural properties showed that when Zn increased to > 4wt%, a NiZn alloy was formed. The improved catalytic activity for 6.5Ni–6.5Zn/SiO2, 4Ni–9Zn/SiO2 and 2Ni–11Zn/SiO2 was attributed to the formation of the NiZn alloy, with smaller particle size and blocked hydrogenolysis sites due to strong Ni–Zn interactions. Propene selectivity equalled 49%, 54% and 64% for the 6.5Ni–6.5Zn/SiO2, 4Ni–9Zn/SiO2 and 2Ni–11Zn/SiO2 catalysts compared to 0% for the monometallic 13Ni/SiO2 catalyst. In the Ni–Zn bimetallic system, zinc had a higher affinity for sulfur and inhibited the formation of a Ni–S phase. Propene selectivity increased from 8% for 9Ni–4Zn/SiO2 to 64% for 9Ni–4Zn/SiO2–S in three minutes of reaction time. Zinc and sulfur exhibited beneficial geometric and electronic effects, which affect particle size and olefin desorption for improved dehydrogenation activity. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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