TiO2-supported rhenium oxide catalysts for methanol oxidation: Effect of support texture on the structure and reactivity evidenced by an operando Raman study

The methanol conversion to methylal over two TiO2-anatase supported oxorhenate catalysts was investigated using operando Raman spectroscopy and compared to the catalytic activities afforded by a classical test. In dehydrated catalysts, two distinct structures were clearly identified and correlated to different catalytic behavior upon CH3OH/He–CH3OH/He/O2–O2 cycling. Such differences, intimately linked to the rhenium surface coverage, are proposed to reflect different degrees of polymerization.