Isobutane Dehydrogenation over InPtSn/ZnAl₂O₄ Catalysts: Effect of Indium Promoter

Abstract

Dehydrogenation of saturated isobutane provides an alternative process to produce isobutene from nonpetroleum resources. InPtSn/ZnAl 2 O 4 catalysts with various In contents were prepared by sequential impregnation for the isobutane dehydrogenation. The catalysts were investigated by several characterizations such as X-ray diffraction, N 2 adsorption, H 2 chemisorption, NH 3 temperature programmed desorption, pyridine-adsorbed Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, and temperature-programmed oxidation. We reveal that with the suitable addition of In component in the PtSn/ZnAl 2 O 4 catalysts, the Pt dispersion increases, and the surface acidity decreases. The presence of In improves the stability of the reaction greatly because it is beneficial to stabilize the oxidation states of SnO x . The excessive addition of In will lead to decrease of the Pt dispersion and increase of the surface acidity, which cause the decline in the catalytic activity. The addition of 0.4 wt % In on PtSn/ZnAl 2 O 4 catalyst shows the optimized catalytic performance. The isobutane conversion decreases from 54.7 to 40.5% within 8 h, and the isobutene selectivity is above 95% even after 20 reaction−regeneration cycles.

Silica-supported, narrowly distributed, subnanometric Pt–Zn particles from single sites with high propane dehydrogenation performance

“…beneficially influenced the catalyst performance as compared to monometallic Pt catalysts. 4–9 While the selectivity for most of the systems reaches high levels, all of them suffer from deactivation. Zn, a highly abundant and non-toxic metal, is of special interest as the second component in bimetallic systems for PDH but has been studied less extensively when compared to more prominent post-transition-metals Sn and Ga. 3,10 …”

Recent Progress in Commercial and Novel Catalysts for Catalytic Dehydrogenation of Light Alkanes

“…The introduction of In has been reported to improve the dispersion of the Pt particles and cover the low‐coordinated step Pt atoms, thus suppressing the undesired hydrogenolysis reaction . The surface acidity was reduced, the oxidation state of Sn was stabilized, and coke formation was suppressed consequently . Searles et al .…”

A Robust and Efficient Propane Dehydrogenation Catalyst from Unexpectedly Segregated Pt2Mn Nanoparticles

“…In order to find suitable materials, research efforts have concentrated on the use of post transition metal or main group element promoters like Zn [6][7][8][9][10][11][12][13] , B 14,15 , Ga [16][17][18][19][20] , In [21][22][23] and Sn 1,5,24 in combination with varying supports. All these promoters are known to drastically increase the PDH performance compared to monometallic Pt by increasing both selectivity and stability.…”