Photocatalytic Decomposition of N2O on Highly Dispersed Ag+ Ions on TiO2 Prepared by Photodeposition

Nitrous oxide (N2O) was photocatalytically decomposed on Ag-photodeposited TiO2 in the presence of methanol vapor. The N2O decomposition activity of Ag-photodeposited TiO2 was much higher than that of Ag-loaded TiO2 prepared by deposition–precipitation or impregnation methods. The difference in the N2O decomposition activity between the preparation methods was discussed in terms of the surface conditions observed by transmittance electron microscopy and X-ray photoelectron spectroscopy. The N2O decomposition activity depended on the amount of photodeposited Ag, and the TiO2 loaded with only 0.16 wt% Ag has revealed the highest level of activity. Highly dispersed Ag+ ions prepared by photodeposition were effective for the photocatalytic decomposition of N2O. In the deposition–precipitation or impregnation methods, Ag+ ions aggregated to form Ag particles and the N2O decomposition activity of these catalysts showed a low level of efficiency. Nitrogen of N2O was reduced into N2 gas, whereas oxygen was released as CO or CO2 by the reaction with methanol or its derivatives.