Catalytic performances and correlations with metal oxide band gaps of metal-tungsten mixed oxide catalysts in propane oxydehydrogenation

Summary

Tungsten-based catalysts of the form X wt.% Na₂WO₄/support (where X = 5, 10, 50 or 75 and the support is either γ-Al₂O₃ or SiO₂) were prepared by impregnation method and tested for oxidative dehydrogenation of propane. The effects of Na₂WO₄ loadings on catalyst performances were more pronounced on γ-Al₂O₃ - supported sample. Individual first-row transition metals (V, Cr, Mn, Co, Ni or Zn) were doped on NaWSi. CoWSi exhibited the best improvement, with conversion of 10.7% and selectivity to propylene of 52.9% at 450^oC. The metal oxide band gaps were correlated with catalyst performances. At a constant propane conversion, strong correlations were observed between the band gaps and respective CO and CO₂ yields. This offers insight into relationship between the species conductivities and the products distributions.