Morphology dependence of Nb2O5 Supported Cobalt oxide on Catalytic Toluene Oxidation

Abstract

The research described the preparation of cobalt-based catalysts supported on Nb2O5 substrates with various forms: rods (Nb2O5-R), grids (Nb2O5-G), and sphere-like structures (Nb2O5-S). These catalysts demonstrated diverse reactivity in toluene oxidation, which correlated with their individual physical and chemical traits and the interfacial interaction between the cobalt oxide and the Nb2O5 support. Notably, the catalyst with a spherical Nb2O5 support (CoOx/Nb2O5-S) outperformed and showed the best activity on oxidizing toluene. The investigation underscored the role of the Nb2O5 substrate's unique features in augmenting the catalyst's efficacy in toluene adsorption and activation. Density Functional Theory (DFT) revealed more facile toluene adsorption on CoOx/Nb2O5-S (-0.65 eV) and reduced energy requirements for oxygen vacancy creation and adsorption. This suggested that the CoOx/Nb2O5-S catalyst enhanced surface oxygen mobility and boosted catalytic efficiency.