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Effect of Acidic Peptization on Formation of Highly Photoactive TiO 2 Films Prepared without Heat Treatment
Author(s) -
Vinogradov Alexandr Valentinovich,
Vinogradov Vladimir Valentinovich
Publication year - 2014
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/jace.12560
Subject(s) - peptization , chemical engineering , aqueous solution , photocatalysis , dynamic light scattering , materials science , colloid , crystallite , nanoparticle , rutile , chemistry , nanotechnology , organic chemistry , catalysis , crystallography , engineering
Nowadays, it is a great challenge to synthesize crystalline TiO 2 nanostructures using low‐temperature methods without annealing stage. Such an approach allows to perform functional and structural modification in the formed crystalline phase by thermally unstable compounds, such as biomaterials, MOF s, dye sets in situ , which was previously considered impossible. In this work, we have developed and analyzed the effect of acidic peptization on formation of highly photoactive titania crystallites in an aqueous solution using titanium tetraisopropylate as a precursor. Acids with different dissociation degrees in water were used as peptizing mediators to determine the effect of protonation on sol formation. The dip‐coating films were obtained with consequent drying of the sols via evaporation of the solvent. The as‐prepared catalysts were characterized by X‐ray diffraction, AFM microscopy, UV –V is spectroscopy, Brunauer–Emmett–Teller surface area. The aggregate size of TiO 2 in the colloidal suspension solution was measured by dynamic light scattering. Photocatalytic activity of films was studied by decomposition of Rhodamine B dye. It is found that the size of colloids in an aqueous solution is proportional to the protonation degree of the surface of particles and does not depend on the [ Ti 4+ ]/[ H + ] ratio, and peptization under weakly acidic conditions leads to anisotropic rod‐like nanoparticles. The highest photocatalytic activity was exhibited by the TiO 2 – HCl ‐based coatings, ~3.5 times higher than that of the Acet.‐prepared sample.