Ga3+-stabilized Pt in PtSn-Mg(Ga)(Al)O catalyst for promoting ethane dehydrogenation

Abstract

A series of catalysts [PtSn-Mg(Ga)(Al)O, Pt-Mg(Ga)(Al)O, PtSn-Mg(Al)O, Pt-Mg(Al)O, Sn-Mg(Ga)(Al)O, and Sn-Mg(Al)O] were prepared and investigated to understand the roles of Pt, Ga, and Sn in the ethane dehydrogenation reaction. In the catalytic dehydrogenation of ethane, PtSn–Mg(Ga)(Al)O displays excellent specific activity for ethene formation. It obtained 25% conversion of ethane in an ethane-poor feed (10% in nitrogen). This work relates the chemical and electronic properties of the catalysts to the chemical activity. Pt is the active site, and Ga has a promotion effect for ethane dehydrogenation. High-resolution transmission electron spectroscopy and Fourier transform infrared spectroscopic characterizations indicate that the addition of Sn and Ga can reduce the size of metal particles, and there is an electronic interaction between Pt and Ga. Further, we found that the calcined Mg(Ga)(Al)O layer double hydrotalcites contain a small amount of pentacoordinate Ga3+ ions, which are able to disperse and stabilize Pt clusters. The promotion of ethane dehydrogenation activity can be attributed to the electronic interactions between Pt and Ga. This insight may provide a new strategy for designing catalysts for light alkane dehydrogenation.