The effect of Ce, Zn and Co on Pt-based catalysts in propane dehydrogenation

Abstract

The effect of the addition of different promoters, such as, Ce, Zn and Co (0.3, 0.5 and 0.7 wt%) to the trimetallic Pt–Sn–K/Al2O3 catalyst in order to enhance performance of propane dehydrogenation was investigated and characterized with several analytic techniques, including, TPR, XRF, UV analysis, SEM and TGA–DTA. The catalysts were prepared by sequential impregnation of γ-Al2O3 technique. It was found that suitable addition of Zn (0.7 wt%), Ce (0.5 wt%) and Co (0.3 wt%) to the Pt–Sn–K/γ-Al2O3 catalyst can improve the catalytic performance more than the commercial Pt–Sn/γ-Al2O3 catalyst. The best results on Sn reduction was obtained by adding Zn (0.7 wt%) and Co (0.3 wt%) to the trimetallic Pt–Sn–K/Al2O3 catalyst. Ce (0.5 wt%) due to its ability on Pt reduction peak temperature was able to reveal better result. The performance of Pt–Sn–K–Ce0.5–Zn0.7/γ-Al2O3 and Pt–Sn–K–Co0.3–Zn0.7/γ-Al2O3 catalysts were improved by a suitable amount of Ce, Zn and Co Pt–Sn–K–Co0.3–Zn0.7/γ-Al2O3 showed better performance in terms of conversion and propylene selectivity. The synergic effect of Co and Zn can enlarge the Pt reduction peak areas than Pt–Sn–K–Co0.3/γ-Al2O3 and Pt–Sn–K–Zn0.7/γ-Al2O3, so can suppress the coke formation and improve the catalyst performance.