Structure and Catalytic Properties of the NaSn/ZSM-5 Catalyst for Propane Dehydrogenation

In this study, ZSM-5 was used as the carrier of the Sn-based catalyst. As for the bare ZSM-5 sample, it exhibits a high conversion of propane, but high selectivities to light hydrocarbons (such as methane and ethene) and a poor selectivity to propene indicate that ZSM-5 tends to catalyze side reactions, such as cracking reactions, rather than dehydrogenation reaction. The systematic characterizations illustrate that added Sn species exist in the external and internal surfaces of the main channels and catalyze propane dehydrogenation to propene. In addition, the introduced Sn species also decrease the acidity of the carrier and weaken the interaction between propene and carrier, resulting in an improved propene selectivity. Besides, Na was also introduced to enhance the propene selectivity. It is proven that appropriate Na can inhibit cracking reactions of propane and prevent propene from further reaction.