Anti-coke behavior of an alumina nanosheet supported Pt–Sn catalyst for isobutane dehydrogenation

Abstract

In heterogeneous catalysis, carbon deposition on catalysts during the operating conditions of a reaction can be a disastrous problem, especially when using widely adopted acidic alumina as a support. Designing anti-coke catalysts, with the aim of improving the coking tolerance, and achieving a high catalytic reactivity is highly desirable but always remains challenging. Here, the excellent anti-coke capacity of a laboratory-made catalyst of alumina nanosheets supporting Pt–Sn for isobutane dehydrogenation is reported. The prepared alumina nanosheets showed abundant defect sites and less acidity compared to the commercial product. The results of the CO-DRIFT spectra showed that the electron density of platinum was increased with the stronger electronic interactions between platinum and tin on the alumina nanosheets. The alumina nanosheet supported Pt–Sn catalyst showed an improved stability, selectivity and activity when compared to previously studied alumina supported Pt-based catalysts reported in the literature, under the dehydrogenation of isobutane reaction conditions of over 24 h at 560 °C. The detailed characterization confirmed that coke species were mainly located on the surface of the alumina nanosheets instead of on the metal particles or in the vicinity of the metal particles, thus ensuring good exposure of active sites. The coke species contained more aliphatics with a higher degree of disorder, which facilitated the elimination of coke during the regeneration process. This study demonstrated that rational design of the support structure could be an efficient strategy to govern the coke behaviors of supported catalysts, and thus could be used to provide guidelines for future catalyst design with high reactivity and stability for a variety of catalytic applications.