Photocatalytic Decomposition of N2O Over Ceramics Cordierite/CeO2 Nanoparticles

Abstract

The study is focused on the testing of the photocatalytic ability to decompose nitrous oxide (N2O) over cordierite/CeO2 nanoparticles ceramic photocatalysts. The activity of ceramic materials was compared with the activity of industrially produced TiO2 (Evonik photocatalyst). Photocatalytic decomposition of N2O over the ceramic samples and the TiO2 Evonik was performed in annular batch reactor illuminated with 8 W Hg lamp (λ ═ 254 nm wavelength). Reaction kinetics was well described by pseudo 1st rate law. Photocatalytic activity of cordierite/CeO2 was better in comparison with TiO2 Evonik P25. The highest N2O conversion (56%) after 20 h of irradiation in inert gas was achieved over the sample with higher amount of CeO2. This photocatalyst sample was examined for photocatalytic activity in the decomposition of N2O in the three various gaseous feed mixtures. The gaseous feed mixtures were: N2O enriched with O2 (6.5 mol.%); N2O enriched with H2O(25 mol.%) and N2O enriched with mixture of O2 and H2O(6.5 mol.% and 25 mol.%, respectively). It is assumed that the reduced conversion of N2O (47%) observed in the flow of the mixture of N2O and H2Ocould be affected by the sorption of water vapor on/onto the photocatalyst “active sites” causing less penetration of light and thus reducing the efficiency of photocatalytic decomposition of N2O. The presence of oxygen in the N2O mixture had only little effect to photocatalytic decomposition of N2O.