The local structudres of silver(I)ion catalysts anchored withiz zeolite cavities and their photocatalytic reactivities for the elimination of N_2O into N_2 and O_2

摘要

Ag~+/ZSM-5 catalysts were prepared by an ion-exachange 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_2O molecules leads to a shift in this band to 220 nm due to the adsorption of N_2O on the Ag~+ ions.The adsorption of N_2O on the Ag~+ ions could also be clarified by the appearance of charactgeristic FT-IR bands at 2251 cm~-1.UV irradiatin of th Ag~+/xsm-5 catalysts in the presence of N_2O led to hte photocatlytic decomposition of N_2O into N_2 and O_2 at temperataures as low as 298 K.It was found the UV light at around 200-250 nm is effective for the reaction,suggeting tha texcitation of the isolated Ag~+ in plays a significant role in the photocatlytic decomposition.of N_2O.