Titanium-containing materials

Abstract

The invention relates to a method of preparing a solution containing colloidal particles which contain crystalline titanium dioxide wherein one or more hydrolysable titanium-containing compound(s) is stabilised by oxalic acid in a reaction medium. The reaction further relates to the preparation of titania materials (including particulate materials, coating solutions and films) which comprise or include anatase phase titania, and so are suitable in photocatalytic applications. The invention also deals with a method of preparing B-phase titania.

Description

[0001] This invention relates to processes for preparing titanium-containing materials. More particularly, it relates to processes of preparing solutions containing colloidal particles containing titanium ions, and to processes for preparing titanium dioxide containing materials from such solutions. This invention also relates to application of these titanium-containing materials.[0002] Titanium-containing composite materials have a range of applications. These include applications that depend on the ability of these materials to function as photocatalysts, constituents of film electrodes, hydrophilic surfaces, and to prevent the growth of micro-organisms.[0003] Photocatalysts[0004] Photocatalysis using titania and titania-based materials have been widely described in recent years for water treatment and air purification (Hoffmann, Martin, Choi and Bahnemann, Chem. Rev. 1995, 95, 69). Anatase was reported to be the most active phase of TiO.sub.2 with a band gap of 3.2 eV (387 nm). T...

AI Technical Summary

Benefits of technology

[0083] ii) curing of the gel (a curing step) to remove or reduce the quantity of the oxalic acid and / or any one or more additives.

[0188] Alternatively addition of substantially up to 50% by weight silica results in stabilisation of the anatase and / or TiO.sub.2--B phase thereby requiring heating to over 600.degree. C. to initiate and / or complete the transformation to rutile phase.

Problems solved by technology

Building surfaces like windows and tiles, automobile screens and mirrors, etc. may attract all sorts of contaminants such as oil deposits, smoke and dust.

Windows, mirrors and other surfaces are fogged when cold due to the condensation of moisture droplets.

Many VOCs such as formaldehyde, toluene trichloroethylene (TCE), ethylene, etc. are considered toxic, carcinogenic, irritant or harmful to a different extent.

Some of these are considered easy to photodegrade such as formaldehyde, while others, such as toluene and ethylene, are considered difficult to decompose.

This can create problems in storing or transporting different produce in the same cold store or container.

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