Highly efficient Bi-promoted ZrO₂-based materials for non-oxidative propane dehydrogenation

Abstract

Surface or bulk promotion of ZrO2-based catalysts with Bi2O3 facilitates removal of lattice oxygen from ZrO2 under reductive conditions resulting in formation of coordinatively unsaturated Zr cations. The catalysts demonstrated...

Morphology Effect of ZrO2 on Tuning the C–H Bond Activation in Propane Dehydrogenation

“…Two coordinatively unsaturated Zr cations situated near an oxygen vacancy (Zr cus –Zr cus ) are determined as the active site over ZrO 2 -based catalysts in the PDH reaction from density functional theory calculations, and the rate-determining step is H 2 formation, which is different from most other PDH catalysts where C–H bond activation shows the highest reaction barrier . The concentration of Zr cus sites and catalytic performance of ZrO 2 -based materials in PDH reaction could be tuned by (1) crystallite size and phase composition ,, (monoclinic, tetragonal, or mixed phase), (2) doped metals − (Y, La, Ga, Cr, Bi), (3) supported metal nanoparticles, − and (4) reducing agents, reduction temperature, and time. Although the above different modification methods have been proven effective in increasing propene formation rate and regulating C–H bond activation in PDH reaction, more elaborate control of the coordination state of zirconium cations, such as their location on certain facets and/or the morphology of ZrO 2 crystallites, is still not systematically investigated.…”