Spectroscopic studies of NO reduction on Pt/TiO2 catalysts

2 wt.% Pt/TiO2 catalyst was prepared by photochemical deposition (PCD) method with UV irradiation on an aqueous TiO2 suspension containing hexachloroplatinic acid. The prepared catalyst exhibits nano-particles of Pt (∼3 nm) uniformly dispersed on TiO2 surface as evidenced by TEM. In situ FT-IR spectroscopic studies indicated that the catalyst exhibits high capacity for chemisorption of NO that led to highly catalytic activity for NO reduction. The temperature programmed desorption profile of NO indicates that adsorption of NO was enhanced thermally and reduced to the major product of N2 with minor N2O on the prepared Pt/TiO2 catalyst. Photodecomposition of NO was investigated by in situ DRIFT and EPR spectroscopy. The photocatalytic activity of the catalyst is highly dependent on its pretreatment. The catalyst after reduction in hydrogen at 300 °C is highly active for NO photodecomposition to N2 and N2O. The XPS spectra indicated the mixed valence-states of Pt (Ptn+ and Pt0) presented on the catalyst surface that incorporated with reducible TiO2 support to present the super catalytic property of the PCD-prepared Pt/TiO2 catalyst.