Photocatalytic Decomposition of N₂O Over Ceramics Cordierite/CeO₂ Nanoparticles.

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.