Raman spectroscopy, monolayer dispersion

The nature of supported oxides and of the support plays a critical role in the partial oxidation of hydrocarbons since the support is not only providing a high surface area, but also dispersing the oxide. The interaction between the metal oxide overlayer and the imderlying support similarly determines the performance of the catalyst, which may also be affected by the exposed sites of the support. To fully understand these effects, a series of supported vanadium oxide catalysts at monolayer and submonolayer coverage have been prepared. The monolayer coverage was determined hy Raman spectroscopy and X -ray photoelectron spectroscopy. The activity of the supported vanadium oxide catalysts is determined by the specific support and surface vanadia coverage. 

Raman spectroscopy demonstrated 100% dispersion of the supported vanadia phase. The number of molecules reacted was determined by the conversion of the reactants, under differential reaction conditions and the absence of heat and mass transfer limitations, in fixed-bed reactor studies. The TOFs for several oxidation reactions over V205n i02 catalysts, monolayer coverage for this Ti02 support (Degussa P-25, 55 m /g) corresponds to 6% V20s/Ti02, are presented in Figure 1. 

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