Understanding the Reactivity of the Tetrahedrally Coordinated High-Valence d⁰ Transition Metal Oxides toward the C−H Bond Activation of Alkanes:  A Cluster Model Study

Abstract

We have carried out a theoretical study on the structure-function relationship for the selective oxidation of lower alkanes (C1-C4). The H abstraction mechanism has been examined over the model catalysts of high-valence d0 transition metal oxides in the tetrahedral coordination. The intrinsic connections among the H abstraction barrier, the strengths of the O-H and the M-O bonds, the ability of electron transfer, as well as the energy gap of frontier orbitals of the oxides have been rationalized in terms of thermodynamics cycles and the frontier orbital analysis. In particular, we emphasize the role that the O-H bond strength plays in determining the reactivity of a metal oxide.

Synergetic effect of VOx and TeOx species in mesoporous SiO2 on selective oxidation of propane to acrolein

“…Extensive studies have concluded that the initial methylene CAH bond breaking is the rate-determining step in the propane oxidation reaction, and the surface V 5+ @O site is generally considered to be the active center [51][52][53][54][55]. In the case of 3%VTe z O x -MS catalysts, vanadium species existed predominantly as tetrahedral V 5+ sites with a terminal V@O bond.…”

Understanding trends in C–H bond activation in heterogeneous catalysis

“…Hydrogen affinity (E " ) has previously been shown to be a suitable descriptor of reactivity for radical hydrocarbon activation [23][24][25] . However, these analyses have traditionally been limited to trends within groups of certain transition metal oxides.…”

“…Traditionally, most of the reported descriptor approaches have been limited to describing one reaction within a single class of catalyst materials 2,[23][24][25][26] . In this work, we have shown that hydrocarbon activation provides a unique opportunity for the development of a universal scaling relationship that accurately describes a vast library of catalyst materials and reactions, which has not been previously demonstrated.…”

Conversion of Methane into Liquid Fuels—Bridging Thermal Catalysis with Electrocatalysis

“…Hydrogen affinity or hydrogen adsorption energy (E H ), defined as the energy difference between hydrogenated and bare active sites, is an activity descriptor for CH bond activation on transition metal oxides that undergoes radical-like transition states. [67,68] Nørskov and co-workers further demonstrated that E H is a universal descriptor for predicting CH activation barriers of methane over a wide range of catalysts that proceed via similar radical transition states. [69] Their calculations covered certain types of metals, metal oxides, metal-exchanged zeolites, metal-organic frameworks (MOFs), and metal-embedded graphene.…”