In-situ FTIR spectroscopic study of the mechanism of photocatalytic reduction of NO with methane over Pt/TiO2 photocatalysts

Photo-selective catalytic reduction of nitric oxide (NO) with methane (CH4) over TiO2 and Pt/TiO2 photocatalysts was studied at reaction temperatures of 25, 50, and 100 °C. The activity of Pt/TiO2 in NO reduction was better than that of TiO2. Conversion of NO by use of Pt/TiO2 and UV irradiation was up to 86.4 %. In-situ Fourier-transform infrared spectroscopy was successfully used to monitor the photoreaction process on TiO2 and Pt/TiO2 photocatalysts. During irradiation with UV light, bidentate nitrite disappeared and bidentate nitrate, monodentate nitrate, and isocyanate, an important intermediate, were generated. Adsorbed NH2 was found to be the final product of NO reduction after UV irradiation. We concluded that NO could be effectively reduced by CH4 under light irradiation at temperatures below 100 °C. A possible reaction mechanism is proposed on the basis of the intermediates and products generated by the photocatalyst under UV light irradiation.