Microstructure-performance study of cerium-doped TiO2 prepared by using pressurized fluids in photocatalytic mitigation of N2O

Parent TiO 2 and cerium-doped TiO 2 photocatalysts with various Ce molar loadings (Ce 0.05 Ti 0.95 O 2 , Ce 0.30 Ti 0.70 O 2 ) were prepared unconventionally using the sol–gel process controlled within the reverse micelles and the processing by pressurized hot fluids as an alternative to standard calcination. Purity, textural, micro/structural and optical properties of prepared photocatalysts were characterized by organic elementary analysis, nitrogen physisorption, powder X-ray diffraction, and DRS UV–Vis spectroscopy. The activity of developed cerium-doped TiO 2 catalysts was investigated in the photocatalytic decomposition of N 2 O for the first time. It was revealed that photocatalysts processed by pressurized hot fluids show significantly improved textural properties and different crystallinity compared to their calcined analogues. Ce loading as well as the processing procedure had a key effect on the crystallization of Ce x Ti 1−x O 2 materials. The maximum N 2 O conversion (77 % after 20 h of illumination) in inert gas was reached over the Ce 0.05 Ti 0.95 O 2 photocatalyst and it can be attributed to the simultaneous N 2 O photocatalytic decomposition and N 2 O photolysis. Reaction kinetics of N 2 O photocatalytic decomposition was described well by the pseudo-first-rate law. The lower photocatalytic activity of the Ce 0.30 Ti 0.70 O 2 photocatalyst compared to the Ce 0.05 Ti 0.95 O 2 photocatalyst can be correlated with two factors; the lower disorder within anatase crystal structure and possible presence of some cerium-containing amorphous phase (e.g., CeO 2 or CeTi 2 O 6 ), which can partially block the surface active sites within the anatase crystal structure.