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Verfahren zur Abscheidung von Titanoxid-Schichten unter Verwendung von loeslichen Pulvern

Titanium oxide layer preparation, e.g. for use in photocatalytic waste water purification, by sol-gel method using titanium-containing soluble powder obtained from alcoholate and complexing agent.
 
: Loebmann, P.; Jahn, R.; Merklein, S.

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DE 1998-19845291 A: 19981001
DE 1998-19845291 A: 19981001
EP 1999-946067 AW: 19990830
WO 1999-EP6374 A: 19990830
DE 19845291 A1: 20000413
EP 1045815 B1: 20031029
C01G0023
C01G0023
Deutsch
Patent, Elektronische Publikation
Fraunhofer ISC ()

Abstract
Beschrieben wird ein Sol-Gel-Verfahren zur Herstellung von Titanoxid-Schichten, das die folgenden Stufen umfasst: (i) Herstellung eines loeslichen, titanhaltigen Pulvers durch: (a) Umsetzung eines Titanalkoholats der allgemeinen Formel Ti(OR)4, in der die Reste R gleich oder verschieden sind und geradkettige, verzweigte oder cyclische Alkyl- oder Alkenylreste mit 1 bis 10 Kohlenstoffatomen darstellen, die gegebenenfalls ein oder mehrere Carbonyl- und/oder Ester- und/oder Carboxylfunktionen aufweisen, mit einer oder mehreren polaren Verbindungen mit komplexierenden, chelatisierenden Eigenschaften, (b) Erhitzen der Loesung, (c) Versetzen der Loesung mit Wasser, gegebenenfalls in Anwesenheit eines Katalysators, (d) Einengen der Loesung bis zum Erhalten eines Pulvers, (ii) Loesen des Pulvers unter Bildung eines Sols, (iii) Beschichtung eines Substrats mit dem Sol und (iv) Tempern des beschichteten Substrats.

 

DE 19845291 A UPAB: 20000613 NOVELTY - A sol-gel method for preparing titanium oxide layers involves preparing a soluble powder (I) containing titanium, dissolving (I), coating a substrate with the obtained sol and tempering, where (I) is prepared by reacting a titanium alcoholate with a polar complexing and chelating agent, heating the solution, treating with water and concentrating. DETAILED DESCRIPTION - A sol-gel method for preparing titanium oxide layers involves preparing a soluble powder (I) containing titanium, dissolving the powder to form a sol, coating a substrate with the sol and tempering the coated substrate. Preparation of (I) is carried out by: (a) reacting a titanium alcoholate of formula Ti(OR)4 (II) with at least one polar compound (III) having complexing and chelating properties; (b) heating the solution; (c) treating the solution with water, optionally in presence of a catalyst; and (d) concentrating the solution. R = linear, branched or cyclic alkyl or alkenyl of 1-10C, optionally having one or more carbonyl, ester and/or carboxy functions. INDEPENDENT CLAIMS are included for: (i) a titanium-containing powder (I') for the deposition of titanium oxide layers, obtained by steps (a)-(d) as above except that the titanium alcoholate is not restricted to formula (II) and (ii) a coating solution for the preparation of titanium oxide layers, comprising a colloidal solution of (I') in an alcohol, diol, amine and/or water. USE - The method is specifically used for applying titanium oxide layers to substrates of glass (especially borate glass), ceramic and/or metal, particularly in tubular or flat form (all claimed). The use of (I') or its collodial solution is claimed in: (i) preparation of electrochromic imaging screens, optical reflection layers or photo-anodes; (ii) preparation of microstructured layers; or (iii) photocatalytic purification of waste waters. ADVANTAGE - The process allows TiO2 layers of relatively high thickness (e.g. above 150 nm) to be deposited in a single stage. The coatings can be applied to large areas of substrates of a wide range of materials and geometries. Drying of wet films before pyrolysis is unnecessary. The layers have good adhesion, even to borosilicate glass. The method can be used to prepare e.g. layers more than 0.4 mu m thick having a net-like fissure structure, finely structured layers (using additives such as polyethylene glycol) and/or layers doped with other materials such as transition or rare earth metals. (I)/(I') can be used to prepare solutions having a high TiO2 solids content, dissolve without residue formation in a wide range of solvents and can be stored in air indefinitely.

: http://publica.fraunhofer.de/dokumente/PX-63476.html