Influence of Phase Composition of Bulk Tungsten Vanadium Oxides on the Aerobic Transformation of Methanol and Glycerol

A series of W–V–O catalysts with different m‐WO 3 and h‐WO 3 phase contents were hydrothermally synthesized by employing different tungsten, vanadium, and ammonium precursors and characterized by powder XRD, N 2 adsorption, SEM, X‐ray energy‐dispersive spectroscopy, thermogravimetric analysis, Raman and FTIR spectroscopy, NH 3 temperature programmed desorption, H 2 temperature‐programmed reduction, and XPS. Finally, the acid/redox properties were analyzed by using aerobic transformation of methanol as a characterization reaction. A correlation between phase composition as well as acid and redox properties was observed, which were correlated to the catalytic performance of the title materials in a one‐pot oxydehydration reaction of glycerol. The hexagonal tungsten bronze (h‐WO 3 ) phase shows a significantly higher concentration of acid sites than monoclinic m‐WO 3 , so that the acid properties of W–V–O oxides are directly related to the presence of h‐WO 3 crystals. The presence of a higher concentration of acid sites in V‐containing h‐WO 3 crystals is a key factor to achieve high selectivity to both acrolein and acrylic acid during one‐pot glycerol oxydehydration. Also, V sites in h‐WO 3 show higher selectivity in the consecutive reaction (partial oxidation of acrolein to acrylic acid), while V sites in the m‐WO 3 phase fundamentally lead to the formation of carbon oxides.