Fourier transform infrared spectroscopic study of surface acidity by pyridine adsorption on the M1 active phase of the MoVTe(Sb)NbO catalysts used in propane oxidation

The adsorption of pyridine on the surface of the M1 active phase of the MoVTe(Sb)O catalysts has been studied for the determination of the Brønsted and Lewis acid sites. The results obtained showed medium Lewis and Brønsted acidity for antimony containing phases and low Lewis and Brønsted acidity for tellurium ones. The incorporation of niobium in the M1 phases resulted in a decrease of both acidities. The samples characterized have been tested as catalysts in the oxidation of propane to acrylic acid. The results obtained allowed to propose correlations between the acidic properties and the catalytic selectivity.