Grafting TiO2 on MCM-41 as a TiO2 support for vanadia for catalytic oxidation of ethanol—EXAFS and XANES analyses of vanadium

Titanium oxide was grafted on the surface of MCM-41 to produce a mesoporous TiO2/MCM-41 composite to serve as a catalyst support. Vanadia was grafted on this titania support to produce V2O5/TiO2/MCM-41 and catalytic oxidation of ethanol by air was used as a probe reaction to study the influence of the support on the catalytic behavior of this catalyst. Catalyst V2O5/TiO2/MCM-41 has reactivity five times higher than the reactivity of vanadia on MCM-41. EXAFS analysis of vanadium indicates that vanadia on both supports have similar structures and polymeric morphologies. The enhancement of reactivity was due to the direct dispersion of vanadia on TiO2 in V2O5/TiO2/MCM-41 as indicated by the EXAFS and XANES studies. This TiO2-grafted MCM-41 mesoporous framework thus has high potential for use as a mesoporous TiO2 support. Such support is superior to traditional anatase TiO2, pure mesoporous TiO2, or TiO2/SiO2 supports owing to its much larger surface area and better thermal stability at elevated temperatures.