Catalytic Combustion of Propane over MnNbOx Composite Oxides: The Promotional Role of Niobium

Metal-doping is an efficient strategy to develop high-activity composite metal oxides catalysts for VOCs abatement. Herein, MnNbOₓ composite oxides were prepared using niobium element as a modification additive, finding that niobium addition presented a promotional effect on boosting the catalytic activity of MnOₓ for propane combustion. It was demonstrated that niobium insertion into manganese oxides was in favor of the formation of Mn₃O₄ crystalline phase and concurrently caused higher redox ability, more abundant surface oxygen species, and acid sites. All these properties were considered to be crucial parameters for catalytic activity enhancement. Among all, the catalyst of Mn₀.₈₅Nb₀.₁₅Oₓ (simply designated as M₀.₈₅N₀.₁₅) showed the highest propane conversion efficiency and relatively good catalytic durability under CO₂-containing atmospheres. Moreover, the in situ DRIFTs analysis highlighted the important role of surface acidity in the surface catalytic pathways of propane adsorption, activation, and oxidation.