Atomically dispersed zinc sites confined in a layered silicalite-2 zeolite with enhanced stability for propane dehydrogenation

The goal of obtaining non-oxidative propane dehydrogenation (PDH) catalysts with low cost and environmental friendliness as alternatives to Pt and Cr-based catalysts, has been pursued for years. Zn-based catalysts have demonstrated great potential in the PDH process, but their activity and stability still need to be improved. Herein, we report a Zn-based zeolite catalyst with atomic Zn active sites that are highly dispersed and confined in a layered-like pure silica zeolite (Silicalite-2), via one-pot hydrothermal synthesis using a ligand-protection method. The atomic dispersion of isolated Zn²⁺ species and their successful trapping and stabilizing by Si−OH in pure-silica LS-2-150 zeolite are unambiguously corroborated using complementary characterization techniques. In PDH reaction (550 °C, WHSV = 2.4 h⁻¹), the optimized Zn_2.65 %@LS-2 exhibits excellent initial activity (the propane conversion at 32.2 % and the propene selectivity at 90.1 %) and good catalytic stability after 6 cycles for 60 h on stream (the deactivation rate of 0.0087 h⁻¹). Thus, this work presents a highly active and more durable Zn-based zeolite catalyst that is promising for PDH applications.