Ultrathin TiO_x Nanosheets Rich in Tetracoordinated Ti Sites for Propane Dehydrogenation

Propane dehydrogenation (PDH) exhibits promising potential for propylene production. However, the primary challenge of its application is the development of environmentally benign, low-cost, and high-performance catalysts as alternatives to CrOx- or Pt-based catalysts. This paper describes the design of highly dispersed, around 2-atomic-layer-thick TiOx ultrathin nanosheet catalysts with a high formation rate of propylene (0.175 mol·gTi–1·h–1) and steady-state selectivity toward propylene close to 93% with a low deactivation rate constant (kd) (0.0126 h–1) and robust regeneration performance at 600 °C. A combined study of ex/in situ characterization elucidated tetracoordinated titanium atoms (Ti4c) surrounding oxygen vacancies (Ovac) as the more reactive sites, which effectively promote C–H bond activation and/or H2 desorption by altering the binding state of propane molecules during dehydrogenation and recombining with the H extracted from propane to form H2, leading to more enhanced catalytic activity. This work gives enlightenment to strategy for designing highly efficient oxide catalysts by constructing coordinately unsaturated metal centers in the ultrathin nanosheet structure.