Low-temp. solvent evaporation induced crystallization process for preparing crystallized titanium dioxide photocatalyst

A technology of titanium dioxide and photocatalyst, which is applied in the direction of catalyst activation/preparation, titanium dioxide, titanium oxide/hydroxide, etc., and can solve the problems of particle growth, specific surface area, decline, etc.

Inactive Publication Date: 2003-08-06
WUHAN UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

But on the other hand, the increase of heat treatment temperature will lead to the growth of particles and the decrease of specific surface area. Titanium dioxide photocatalysts, l...

Method used

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  • Low-temp. solvent evaporation induced crystallization process for preparing crystallized titanium dioxide photocatalyst
  • Low-temp. solvent evaporation induced crystallization process for preparing crystallized titanium dioxide photocatalyst
  • Low-temp. solvent evaporation induced crystallization process for preparing crystallized titanium dioxide photocatalyst

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Embodiment 1

[0020] The method for preparing nanocrystalline titanium dioxide powder photocatalyst by low-temperature solvent evaporation-induced crystallization is as follows: use isopropyl titanate as the titanium source, add 0.063 moles of isopropyl titanate to 113 ml of distilled water dropwise for hydrolysis, and stir vigorously at the same time. For 1 hour, the molar ratio of water to isopropyl titanate was 100:1. After aging the titanium dioxide sol sample obtained by hydrolysis at 25°C for 24 hours, the sample was placed in an oven and gradually evaporated at 100°C to remove water and organic solvent to obtain titanium dioxide xerogel powder. Finally, grind the xerogel finely to obtain titanium dioxide powder photocatalyst.

[0021] figure 1 shows the XRD pattern of titanium dioxide wet gel and xerogel, from figure 1 It can be seen that the titanium dioxide wet gel obtained by the direct hydrolysis of isopropyl titanate is amorphous, however, the titanium dioxide xerogel powder p...

Embodiment 2

[0026] Except that the titanium source used is n-butyl titanate, other reaction conditions such as the concentration of the titanium source, the amount of solvent water, the temperature and time of hydrolysis, aging and solvent evaporation, etc. are all exactly the same as in Example 1, and the obtained titanium dioxide The phase structure and composition of the powder photocatalyst are: anatase accounts for 67%, and brookite phase accounts for 33%. According to the Scherrer formula, the grain sizes of anatase and brookite phases were calculated to be 5.0 and 3.1 nm, respectively. The titanium dioxide photocatalyst prepared with n-butyl titanate as the titanium source also showed very high photocatalytic activity, with an apparent rate constant of 3.72×10 -3 (min -1 ), and the photocatalytic degradation rate constant of Degussa P25 is 4.19×10 -3 (min -1 )near.

Embodiment 3

[0028] The temperature at which the solvent evaporates is 140°C. Except that the temperature of solvent evaporation is different, other reaction conditions such as titanium source, the concentration of titanium source, the amount of solvent water, the temperature and time of hydrolysis and aging, the time of solvent evaporation etc. are all identical with embodiment 1, prepared TiO2 powder photocatalyst showed higher photocatalytic activity with an apparent rate constant of 3.91×10 -3 (min -1 ). This may be due to the better crystallinity of the prepared titanium dioxide powder photocatalyst.

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Abstract

The present invention provides a low-temp. solvent evaporation induced crystallization method for preparing nano crystal titanium dioxide. Said invention method includes the following steps: hydrolyzing alcohol salt of titanium in water, then ageing, finally progressively evaporating solvent at 80-180 deg.C, at the same time inducing titanium dioxide to crystallize so as to obtain the invented nano crystallized titanium dioxide photocatalyst material. By reducing phase-transition temperature the titanium dioxide photocatalyst obtained by said invention possesses high catalytic activity approaching to Degussa P25, large specific surface area (greater than 250 sq.m/g) and small grain size (less than 6nm).

Description

technical field [0001] The invention relates to the preparation technology of a semiconductor oxide nanocrystal material with high specific surface area and small particle size, in particular to a preparation method of a high light activity mesoporous titanium dioxide photocatalytic material. technical background [0002] In recent years, in order to solve the increasingly serious problem of environmental pollution, the research and development of highly active heterogeneous photocatalytic materials has attracted extensive attention from governments and researchers all over the world, because this kind of photocatalytic materials can be widely used in air purification, water purification, etc. Sterilization, degradation and removal of toxic and harmful pollutants in water, etc. Among all kinds of oxide semiconductor photocatalytic materials, practice has proved that titanium dioxide is the most suitable for a wide range of environmental applications, because titanium dioxide...

Claims

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Application Information

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IPC IPC(8): B01J21/06B01J37/03C01G23/053
Inventor 余家国余济美程蓓赵修建
Owner WUHAN UNIV OF TECH
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