Carbon materials as template for the preparation of mixed oxides with controlled morphology and porous structure

• The synthesis and characterization of VPO mixed oxides with spherical morphology are described.
• This synthesis method is simple and low cost.
• These materials present catalytic properties for hydrocarbon activation.

VPO bulk catalysts with spherical morphology and high surface areas have been prepared by the use of a carbon material as template. The carbon material is an activated carbon prepared by the hydrothermal method, using cellulose as starting material. Thus, the synthesis method described is simple and low-cost. The morphology and porous structure of these materials have been characterized by SEM, TEM, N2 and CO2 adsorption isotherms. The chemical composition was analyzed by XPS, XRD and Raman spectroscopy, showing the presence of V2O5 and VPO phases on the surface of these spherical catalysts. Methanol oxidation reaction was used to characterize the active centers on the surface of these materials and showed that both acid and redox sites are present. These materials were also tested during the propane ODH reaction and the results demonstrated that they are able to activate the hydrocarbon selectively to propylene. The characterization of these materials after reaction demonstrated that the morphology and the chemical composition are quite stable under the reaction conditions studied, since both VPO and V2O5 phases are detected. It was also observed that the biggest spheres are not stable during reaction conditions.

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