Effects of adding Al2O3 on the crystal structure of TiO2 and the performance of Pd-based catalysts supported on the composite for the total oxidation of ethanol

TiO2, Al2O3–TiO2 composites, and Pd-based catalysts have been prepared by sol–gel and wet-impregnation methods. N2 absorption, XRD, Pd dispersion, DRIFTS, XPS, 27Al MAS NMR, and ethanol oxidation experiments have been performed to assess the properties of the TiO2 oxides and catalysts. The results showed that the addition of 5 wt.% Al2O3 to TiO2 plays an important role in stabilizing the anatase structure and preventing phase transformation of TiO2. This is ascribed to the formation of Al–O–Ti chemical bonds in Al2O3–TiO2 crystals. Meanwhile, Pd dispersion on the surface of the Al2O3–TiO2 composites is effectively promoted. The activity of Pd/Al2O3–TiO2 for the total oxidation of ethanol is distinctly higher than that of Pd/TiO2.