Ozone decomposition on Ag/SiO₂ and Ag/clinoptilolite catalysts at ambient temperature

Silver modified zeolite (Bulgarian natural clinoptilolite) and Ag/silica catalysts were synthesized by ion exchange and incipient wet impregnation method respectively and characterized by different techniques. DC arc-AES was used for Ag detection. XRD spectra show that Ag is loaded over the surface of the SiO₂ sample and that after the ion-exchange process the HEU type structure of clinoptilolite is retained. UV-VIS (specific reflection at 310nm) and IR (band at 695cm^-1) spectroscopy analysis proved that silver is loaded as a T-atom into zeolite channels as Ag⁺, instead of Na⁺, Ca²⁺, or K⁺ ions, existing in the natural clinoptilolite form. The samples Ag/SiO₂ and Ag-clinoptilolite were tested as catalysts for decomposition of gas phase ozone. Very high catalytic activity (up to 99%) was observed and at the same time the catalysts remained active over time at room temperature.