High-Temperature Formation of Titanate Nanotubes and the Transformation Mechanism of Nanotubes into Nanowires

Abstract

Large-scale pure titanate nanotubes were synthesized through the hydrothermal reaction between TiO 2 powders and concentrated NaOH under an unexpected high temperature of 240 °C, while it was generally claimed that it is impossible to form nanotubes at temperatures higher than 180 °C. The titanate nanotube was found to be an inevitable intermediate product, which finally transformed into a nanowire upon increasing the hydrothermal treatment duration. It was proven that the successive appearance of nanosheets, nanotubes, and nanowires are three unavoidable kinetic products of the reaction. Increasing the temperature could only accelerate the nanotube-nanowire transformation process but could not affect the sequence of the reaction events. The transformation kinetics from nanotubes to nanowires under different reaction temperatures was studied. Detailed studies indicate that this transformation process was accompanied by a coarsening process induced by both oriented attachment (OA) and Ostwald ripening (OR) mechanisms simultaneously; thereafter, the OA-OR cooperative mechanism was proposed.

Titanate Nanotubes Produced From Microwave-Assisted Hydrothermal Synthesis: Characterization, Adsorption and Photocatalytic Activity

“…These also show the presence of unreacted TiO2 nanoparticles. For CH 130-48, we noted the presence of non-tubular or nanoribbon structures (Figure 4b) as reported in other studies (Bavykin et al, 2004;Huang et al, 2009). This explains the low surface area and pore volume presented for this sample.…”

“…This explains the low surface area and pore volume presented for this sample. According to Huang et al (2009), higher reaction times favor the formation of nanoribbons. This is due to dissolution of the nanotube by precipitation of Ti (IV) in the inner and outer surface of the nanotubes, which fills the tube and pores.…”

A Study of Low-Temperature CO Oxidation over Mesoporous CuO-TiO2 Nanotube Catalysts

“…Of particular interest, the hydrothermal treatment method has received great attention owing to the fairly simple synthesis, low cost processing, chemical versatility, and scalability [19][20][21][22][23]. Anil et al [9] have shown that Cu-doping increases the catalytic activity of Mn3O4 for CO oxidation.…”

Synthesis and Growth Mechanism of Net-like Titanate Nanowire Films via Low-temperature and Low-alkali-concentration Route

“…• (indicated by stars), which can be attributed to trititanate [9,11], are also be observed in the XRD pattern of the nanowire film.…”

“…As one of the most effective methods for preparation of 1D titanate nanostructures, the method of hydrothermal treatment of TiO 2 in concentrated alkali solutions has gained great attention [8][9][10][11][12][13] since the pioneering work of Kasuga et al [14]. In general, under relatively lower temperature (e.g.…”