Nanocrystalline N-doped ceria porous thin films as efficient visible-active photocatalysts

Nanocrystalline porous N-doped ceria films have been prepared by combining sol-gel chemistry, evaporation-induced self-assembly (EISA), flash crystallization and treatment in NH sub(3) gas between 550 and 700 degree C at flow rates of 270 and 670 cm super(3) min super(-1). The maximum nitrogen uptake is 0.06 moles per Ce, observed for the sample treated at 600 degree C and NH sub(3) flow rate of 670 cm super(3) min super(-1). Nitrogen bonding to cerium is proved by XPS, through the observation of the characteristic Ce-N feature at similar to 397 eV. Microstructural characterization shows that the mesostructure of the films is lost for treatment temperatures in ammonia higher than 550 degree C but the porous fraction remains between 35 and 40% after ammonolysis for all the samples. The nitrided films show photocatalytic activity under visible light in the acetaldehyde decomposition, with the best results obtained for the films treated at 550 degree C under NH sub(3) flow rate of 670 cm super(3) min super(-1).