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Mineralogical and Optical Characterization of SiO 2 ‐, N‐, and SiO 2 /N‐Co‐Doped Titania Nanopowders
Author(s) -
Tobaldi David M.,
Gao Lian,
Gualtieri Alessandro F.,
Škapin Andrijana Sever,
Tucci Antonella,
Giacobbe Carlotta
Publication year - 2012
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2012.05135.x
Subject(s) - anatase , materials science , rutile , doping , rietveld refinement , diffuse reflectance infrared fourier transform , visible spectrum , photocatalysis , analytical chemistry (journal) , high resolution transmission electron microscopy , amorphous solid , crystal structure , mineralogy , chemical engineering , crystallography , nanotechnology , chemistry , transmission electron microscopy , organic chemistry , optoelectronics , engineering , catalysis
Silica, nitrogen, and nitrogen‐plus‐silica co‐doped titania powders were synthesized via sol–gel method. The products of the synthesis were thermally treated in air and under ammonia flow. The determination of S i and/or N into the T i O 2 lattice, and the doped samples' crystal structure, was made by means of X ‐ray powder diffraction, whilst the occurrence of amorphous phase was obtained using the combined Rietveld‐ RIR method. The optical properties of the powders were obtained by diffuse reflectance spectroscopy and their energy band gaps were calculated using the differential reflectance method. The photocatalytic activity of the doped samples was assessed in gas phase under UV ‐light and visible‐light irradiation, monitoring the degradation of an organic compound. In addition, the morphology of the samples was further on characterized by means of HRTEM . Nitrogen, silica, and co‐doping shifted the anatase‐to‐rutile (A → R) phase transition toward higher temperatures. Silica was found to enter the anatase lattice, and nitrogen was presumed to enter the titania crystal structure as well. Nitrogen doping and S i O 2 / N ‐co‐doping shifted the light absorption toward the visible region.