Improved catalytic stability of PtSnIn/xCa–Al catalysts for propane dehydrogenation to propylene

•High catalytic stability of PtSnIn/xCa–Al catalysts for propane dehydrogenation.•PtSnIn/1.5Ca–Al catalyst exhibits the highest catalytic stability.•Propane conversion has little decline after 25 h for PtSnIn/1.5Ca–Al catalyst.

The catalytic stability of the trimetallic PtSnIn supported catalysts for propane dehydrogenation reaction is markedly improved by using Ca-doped γ-Al2O3 as support. The NH3-TPD measurements verify that the surface acidity of the synthesized PtSnIn/xCa–Al catalysts decreases with the addition of Ca. The TEM images reveal that PtSnIn/1.5Ca–Al catalyst has the smallest Pt particle size of 5 nm and satisfied particle distribution. The XPS and H2-TPR verify that the state of metal species and its interaction with support are influenced by Ca species. After adding 0.6–1.5 wt.% Ca species, the catalytic stability of the PtSnIn/xCa–Al catalysts is evidently improved. However, over high Ca loading leads to a decrease of propane conversion and catalytic stability. For PtSnIn/1.5Ca–Al catalyst, the propane conversion has little decline and keep at higher level above 58.0% until 25 h reaction time, and the final propane conversion of 34.0% is obtained even after 100 h reaction.