The electron-rich [ZnH]⁺ species stabilized by titanium silicalite-1 zeolite for propane dehydrogenation

Propane dehydrogenation to propylene has broad application prospects, so it is of great significance to explore low-cost and environmentally friendly catalysts. Metal hydrides, as active sites, exhibit excellent dehydrogenation property. Herein, we report titanium modified [ZnH](+) ([ZnH](+)center dot center dot center dot TiO6) site with high activity (14.49 mmolC(3)H(6).g(cat)(-1).h(-1)) and regeneration performance, which is derived from the in-situ conversion of [ZnOH](+) in the dehydrogenation reaction. Combined with in-situ spectroscopic characterizations and ab initio molecular dynamics (AIMD) simulations, the unique [ZnH](+)center dot center dot center dot TiO6 moiety was confirmed, and the evolution process from [ZnOH]+ to [ZnH]+ was clarified. XPS and AIMD calculations show that Zn in the [ZnH](+)center dot center dot center dot TiO6 structure is in an electron-rich state with high H-affinity, which can effectively reduce the propyl C-H cleavage barriers based on slow-growth simulations. In general, titanium modification can effectively stabilize the [ZnH](+) species and enrich the electrons density of zinc, which contribute to the enhanced PDH performance.