Synthesis of mesoporous titania in rutile phase with pore-stable structure

Abstract

-Metastable-to-stable transformation in oxides is always associated with drastic reduction in surface area and/or porosity. Therefore, all earlier efforts to stabilize the pore structure of oxides undergoing a metastable-to-stable phase transformation are interesting for both scientific and technological concerns. This work presents a new experimental technique for catalytic oxide production through sonication in acid solution for attainment of the anatase-rutile transformation. Mesoporous structure of titania and surface area were stabilized in the rutile phase after calcinations at 430 and 730 o C. Analysis by scanning electron microscopy (SEM) and nitrogen isotherms showed that the mesoporous structure was preserved after calcinations. After the sonication of titania for 32 hours, rutile phase was obtained at 730 o C and still kept a surface area of 28m 2 /g. When sonicated for 64 h, rutile was obtained at 430 o C, still preserving an area of 52m 2 /g.

Influence of elevated surface texture hydrated titania on Ce-doped Mn/TiO2 catalysts for the low-temperature SCR of NO under oxygen-rich conditions

“…Hydrated titania-based catalysts have been used for a diversity of applications, such as support for catalysts, pigment, ceramics, paper industry, cosmetics, and staple fibers that are some of the wide variety of commercial applications. Thermal stability of mesoporous structures is a critical parameter for catalysis applications [17]. The mesoporous TiO 2 offers better performance as catalyst, due to easier accessibility of bigger molecules to the internal channels.…”

Nanocrystalline TiO2 preparation by microwave route and nature of anatase–rutile phase transition in nano TiO2

“…Transformation of ionic layers which undergo excitation could be assisted by the presence of aliovalent impurities which give rise to oxygen vacancies but tend to retain layer integrity. This is evidenced in many reported studies (dos Santos et al 2009). This aspect has not been examined fully in the A → R transformation of nano-TiO 2 .…”

“…In their extensive and insightful investigations of phase transition of TiO 2 , Lee Penn and Banfield (1998) observed that brookite is a polytype of anatase and its inter-conversion only involves the displacement of titanium atoms into adjacent octahedral sites. In somewhat related work on the preparation of mesoporus titania, Correa and co-workers (dos Santos et al 2009) have shown that creation of defects by sonication can bring about anatase-to-rutile transformation at lower temperatures. Banfield and Veblen (1992) have proposed a very attractive transformation mechanism based on a structural concept of 'fundamental building blocks'.…”

Microstructural and optical properties of rare earth ions doped TiO2 for potential white LED applications

“…Further increase in the concentration of dopant above the solubility limit it shows a decrease in both the strain and the lattice constant [27,28]. This may be due to the arrangement of Dy 3+ materials made were of non-stoichiometric with oxygen vacancy that indicates the enhanced photocatalytic activity [29]. This may be due to the incorporation of Dy 3+ , Eu 3+ and Tb 3+ ions which suppresses the growth of TiO 2 nanocrystals to a greater extent.…”

“…It is also observed that the positions are almost invariant and is around 25.22° for all RE doped TiO 2 . This indicates that the incorporation of the RE dopants is responsible for shifting in peak positions[29]. The amalgamation of RE in TiO 2 lattice results in deformation of the lattice arrangement by dislocating Ti 4+ ion due to mismatch in the ionic radii between RE and Ti 4+[30].…”