The Effect of Coating TiO2 on the CO Oxidation of the Pt/γ-Alumina Catalysts

The effect of coating TiO 2 on the CO oxidation of the Pt/γ-alumina catalysts was observed through activity tests and surface characterization spectroscopy by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) experiments. XPS results evidenced the occurrence of different Pt 2+ species and metallic Pt 0 at the surface which suggest electron transfer of titanium (cation) to the platinum atom and the reduction of titanium (Ti 4+ → Ti 3+ ). FTIR analyses suggested oxygen spillover mechanism at the interface between titanium dioxide and platinum that may explain the catalytic activity of the platinum titania-supported catalysts. The apparent activation energy for the CO oxidation was 52.5 kJ/mol and similar for all catalysts. However, the frequency factor changed significantly, indicating interfacial phenomena caused by CO and oxygen adsorptions over TiO x species and Al 2 O 3 support with similar dispersions. Graphical Abstract