Peptization–Hydrothermal Method as a Surfactant‐Free Process toward Nanorod‐Like Anatase TiO₂Nanocrystals

Abstract

The transparent TiO 2 sol contained of anatase crystallites was prepared by peptization of anatase TiO 2 precipitates. With the hydrothermal treatment of TiO 2 sol at 150°C, the dispersible and nanorod-like TiO 2 nanocrystals were formed by an oriented attachment mechanism. After further hydrothermal treatment of the mixture of nanorod-like TiO 2 nanocrystals and the original sol, branched and nanoring-like nanostructures in the anatase phase were obtained. The asprepared TiO 2 nanocrystals were characterized by X-ray diffraction, FT-Raman spectrometry, UV/Vis absorption spectrometry, and transmission electron microscopy (TEM). TEM results indicated that TiO 2 nanocrystals were nanorod-like,

TiO2 Nanorods: A Facile Size- and Shape-Tunable Synthesis and Effective Improvement of Charge Collection Kinetics for Dye-Sensitized Solar Cells

“…In this paper, we present a novel, high-yield, and costeffective hydrothermal method for preparing single crystalline anatase TiO 2 NRs laterally bounded by the {101} crystal planes and preferentially grown in the [001] direction, which was achieved by taking advantage of an "oriented attachment" mechanism. Though, similar morphologies have been reported in the literature variously, 29,30,32,33 several differences of our strategy from others are noteworthy: (1) the whole oriented attachment process was accomplished by a one-pot hydrothermal reaction in one run, (2) the process avoided using expensive solvents or additives, (3) size parameters of the NRs could be finely tuned in the range of 15-25 nm (diameter) × 50−150 nm (length), very suitable for high-performance DSSCs, (4) the NRs are highly dispersible unlike aggregates reported previously which may make it difficult to fully excavate the NRs' potential. The successful synthesis of TiO 2 NRs with tunable diameter and aspect ratio, easily accomplished with our strategy by adjusting the solvent compositions, has allowed us for the first time to conduct comparative studies with nanorods of different size/shape/surface parameters and thereby optimize cell performance while monitoring their charge collection kinetics.…”

Photoanode Based on Chain‐Shaped Anatase TiO2 Nanorods for High‐Efficiency Dye‐Sensitized Solar Cells

“…Consequently, the energy conversion efficiency of 15024 DSSC was increased by 58 % compared with both that of the P25 DSSC and that of a DSSC with nanoparticles derived from peptization and hydrothermal treatment. The DSSC with the photoanode from TiO 2 nanoparticles, referred to as Ti20012h in our previous work, [26] which were peptized and hydrothermally treated at 200 8C for 12 h and possessed a specific surface area of 126 m 2 g À1 but in a cuboid or spherical shape, resulted in a conversion efficiency of 6.12 %. This result suggested that the network con-sisting of chain-shaped nanorods had a crucial effect on the improvement of the conversion efficiency of DSSCs, which also threw light on the fabrication of high-performance DSSCs based on more connected TiO 2 nanorods.…”

Anatase TiO2 sols derived from peroxotitanium acid and to form transparent TiO2 compact film for dye-sensitized solar cells

“…Ammonia (2.0 M) was slowly dropped into a vigorously stirred titanium sulfate solution, which was heated in advance to 70 • C, until the solution pH value was 7. As we reported previously, the precipitates at 70 • C from a titanium salt contained mainly anatase TiO2 in the presence of sulfate ions [39,40]. A white precipitate was formed instantaneously, and a large amount of precipitate was obtained after the ammonia solution was used up.…”