In situ DRIFTS study on the catalytic oxidation of toluene over V2O5/TiO2 under mild conditions

In situ DRIFTS study of toluene oxidation over V–Ti–O catalyst at ambient temperature was presented. Physisorbed benzaldehyde, benzoic acid, benzoate, vanadyl species and carbon dioxide were detected. An analysis of the vanadyl species band and XPS characterization were used to illustrate the reaction route. A reaction mechanism is proposed: monomeric VOx is firstly reduced by the adsorbed species, then oxygen transfers from bulk V2O5 to monomeric VOx for compensation, and the oxygen-deficient bulk V2O5 replenishes oxygen from gas phase. The transference of oxygen from bulk V2O5 to reduced VOx is deemed as the rate determining step below 90 °C.

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► A negative band corresponds to the reduction of vanadyl species over V–Ti–O catalyst.
► Oxygen transfers from gas to bulk V2O5, then to monomeric VOx for toluene oxidation.
► The transfer of oxygen from bulk V2O5 to reduced VOx is determining step below 90 °C.