Construction of highly stable and efficient Zn-based catalyst via Mg modification for propane dehydrogenation

Zn-based catalysts are considered a kind of efficient catalysts for propane dehydrogenation (PDH) because of their low price and non-toxicity. However, Zn-based catalysts still face problems such as the limited diffusion of reaction gas, non-uniform distribution of Zn species, and easy coking. Here, a novel double-layered silicalite-1 (DS-1) support with high specific surface area was synthesized by a crystal growth method, and an alkaline additive modification strategy has been adopted to prepare the Mg-modified Zn-based catalyst (0.1Mg5Zn@DS-1) in order to improve the catalytic activity and stability. The physical characterization results reveal that the Mg modification induces the enhanced electronic interactions between Zn sites and Mg species. Besides, the modified Mg species also reduce the Lewis acidity, allowing easier desorption of propylene and improving the propylene selectivity with anti-coking property. Furthermore, PDH evaluation results demonstrate that the optimal 0.1Mg5Zn@DS-1 catalyst achieves the propylene yield of ∼44 %, propylene selectivity of ∼95 % as well as outstanding stability and regeneration ability. This work provides a novel insight into the design of Zn-based catalysts with high activity and excellent stability.