Influence of Calcium Addition on Catalytic Properties of PtSn/ZSM-5 Catalyst for Propane Dehydrogenation

Abstract

In this work the influence of the Ca addition to PtSn/ZSM-5 catalyst on its performance for propane dehydrogenation was investigated. The catalysts were characterized by X-ray diffraction, BET analysis, TEM, NH 3 -TPD, TPO and TG. Results showed that the addition of calcium could not only modify the characteristics and properties of both acid and metal function but also suppress coke deposits on the catalyst. The addition of 0.9 wt% Ca to PtSn/ZSM-5 prompted catalytic activity. However, the incorporation of excessive Ca resulted in catalyst deactivation. TPR results implied that excessive Ca promoted the reduction of oxidized tin species to Sn 0 . The Sn 0 probably could interact with Pt to produce a PtSn alloy which led to the diminution of catalytic activity.

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

“…The shift and increased intensity may be attributed to the reduction of Pt oxides that interacted with Ca species. Similar results were also revealed by Bai et al [30]. The peaks at about 524°C may be attributed to the reduction of Pt species in stronger interaction with the support and/or the reduction of the trimetallic system(Pt, Sn and In) of PtSnIn/xCa-Al catalysts [40].…”

“…The diffraction peaks of Pt, Sn and In species are not been detected due to their small particle size and/or low concentration below XRD detection limit. Part Ca species may enter into the channels of c-Al 2 O 3 in impregnation process because the average diameter of Ca 2+ (0.204 nm) is less than the average mouth of c-Al 2 O 3 [30]. However, the characteristic peaks of Ca-related crystalline phases are not detected since Ca species are highly dispersed or poorly crystallized on the surfaces of c-Al 2 O 3 [34].…”

“…Many studies were devoted to improving the catalytic performance of Pt-Sn catalysts in propane dehydrogenation reaction by doping additional promoters including rare earth metals (La, Ce, Y), alkali metals (Li, K, Na), alkaline earth metals (Mg, Ca,) and so on [22][23][24][25][26][27][28][29][30]. Among these promoters, Ca additive exhibited a decent ability to improve the stability and dispersion of metal particles, and thus promoted the catalytic performance.…”

Effect of K Addition on Catalytic Performance of PtSn/ZSM-5 Catalyst for Propane Dehydrogenation

“…In our previous study, many studies were carried out on the Pt/ZSM-5 [18][19][20][21][22][23][24]. Promoters such as Sn, Na, La, and Mg have been already added.…”

Dehydroaromatization of methane over Sn–Pt modified Mo/H-ZSM-5 zeolite catalysts: Effect of preparation method

“…The Sn/Pt catalyst exhibited lower conversions compared with other catalysts. This might be due to the formation of a tin oxide layer covering the active sites for the MDA reaction[60].…”