In-situ UV-Visible Spectroscopic Study for Dynamic Analysis of Silver Catalyst

摘要

In-situ UV-visible apparatus was developed for dynamic analysis of solid catalysts under the working state. Ag species on Ag/Al_2O_3 catalysts exhibited high mobility depending on the reaction atmospheres. Isolated Ag~+ ions aggregated to Ag clusters within 30 s in the presence of 5000 ppm H_2. In a flow of NO+O_2, Ag clusters reversibly dispersed into Ag~+ ions within 90 s. The rates of the formation and dispersion of Ag clusters were significantly affected by Ag content. Dynamic analysis of Ag species rationalized the promotion effect of H_2 on the C_3H_8-SCR over Ag/Al_2O_3.