Enhanced Stability and Propene Yield in Propane Dehydrogenation on PtIn/Mg(Al)O Catalysts with Various In Loadings

摘要

The dehydrogenation of propane on In-promoted Pt (0.3?wt% Pt) supported on hydrotalcite Mg(Al)O with different In loadings (0.2–1.0?wt% In) was investigated at 550?°C atmospheric pressure. All the bimetallic PtIn/Mg(Al)O showed higher propane conversion and propene selectivity than the Pt/Mg(Al)O with Pt0.8In exhibited the best catalytic performances with 97.5% propylene selectivity and 27.5% yield after 5?h time-on-stream. The addition of In to the monometallic Pt catalyst could reduce the acidity strength especially the strong acid site. As revealed by the H~(2)-TPR and XPS results, addition of In by impregnation on Pt/Mg(Al)O also led to the formation of metallic In and PtIn alloy, which greatly enhanced the catalyst activity and reduced coke formation on the support. Nevertheless, excessive In loading (i.e., Pt1.0In) resulted in a descending trend of catalyst activity compared to the Pt0.8In, due probably to the large amount of metallic In being formed, which was disadvantageous in propane dehydrogenation.