The Local Structures of Silver(I) Ion Catalysts Anchored within Zeolite Cavities and Their Photocatalytic Reactivities for the Elimination of N2O into N2 and O2

Ag + /ZSM-5 catalysts were prepared by an ion-exchange method and characterized by in-situ XPS, XAFS (XANES and EXAFS), UV−Vis, photoluminescence, and FT-IR investigations. These Ag + /ZSM-5 catalysts were found to exhibit an UV absorption band at around 190 nm due to the isolated Ag + ions. The addition of N 2 O molecules leads to a shift in this band to 220 nm due to the adsorption of N 2 O on the Ag + ions. The adsorption of N 2 O on the Ag + ions could also be clarified by the appearance of characteristic FT-IR bands at 2251 cm -1 . UV irradiation of the Ag + /ZSM-5 catalysts in the presence of N 2 O led to the photocatalytic decomposition of N 2 O into N 2 and O 2 at temperatures as low as 298 K. It was found that UV light at around 200−250 nm is effective for the reaction, suggesting that excitation of the isolated Ag + ion plays a significant role in the photocatalytic decomposition of N 2 O.