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Method for forming oxygen vacancies of metal oxide through oxygen-free catalysis combustion of dichloromethane

A dichloromethane, catalytic combustion technology, applied in the direction of metal/metal oxide/metal hydroxide catalysts, chemical instruments and methods, inorganic chemistry, etc., can solve the problem of poor universal applicability, difficulty in clearly revealing the formation mechanism and reaction conditions Harsh and other issues

Active Publication Date: 2019-11-26
SHAANXI NORMAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, these reaction conditions for forming oxygen vacancies are usually harsh, and it is difficult to reveal the formation mechanism clearly, which leads to the poor general applicability of constructing oxygen vacancies on common metal oxides.
Moreover, other defects may also be generated in the semiconductor during the fabrication process
The type and concentration of material defects generated cannot be well controlled
These are not conducive to a clear understanding of the role of oxygen vacancy defects

Method used

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  • Method for forming oxygen vacancies of metal oxide through oxygen-free catalysis combustion of dichloromethane
  • Method for forming oxygen vacancies of metal oxide through oxygen-free catalysis combustion of dichloromethane
  • Method for forming oxygen vacancies of metal oxide through oxygen-free catalysis combustion of dichloromethane

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Experimental program
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Effect test

Embodiment 1

[0033] 1. Weigh 1.0g anatase TiO 2 Placed in the reaction tube, under dynamic vacuum (continuous vacuuming, keep the vacuum degree at 1.0×10 -2 Pa) at 400°C for 2 hours to remove TiO 2 The adsorbed water is then naturally cooled to room temperature under dynamic vacuum conditions.

[0034] 2. Seal the reaction tube, keep the reaction tube in a vacuum state, put the reaction tube into a Dewar bottle filled with liquid nitrogen, and inject 20 mL of anhydrous and oxygen-free dichloromethane into the TiO through the septum with a syringe 2 Then remove the Dewar bottle, let it stand for adsorption at room temperature for 30 minutes, then dynamically vacuum at room temperature (continuous vacuuming, keep the vacuum degree of 1.0×10 -2 Pa) Treat for 1 hour, pump away the unadsorbed TiO 2 on dichloromethane.

[0035] 3. Seal the reaction tube to keep the vacuum in the reaction tube, heat treatment at 50°C for 4 hours, then vacuum in dynamic vacuum (continuous vacuuming, keep the v...

Embodiment 2

[0037] In the step 3 of embodiment 1, the reaction tube is sealed to still keep a vacuum state in the reaction tube, heat treatment at 100 ° C for 4 hours, and then under dynamic vacuum (continuous vacuuming, keep a vacuum degree of 1.0 × 10 -2 Pa) at 100°C for 2 hours to remove TiO 2 Surface species and some generated gases, other steps are the same as in Example 1, and TiO with oxygen vacancies is obtained 2 (denoted as TiO 2 -100).

Embodiment 3

[0039] In the step 3 of embodiment 1, the reaction tube is sealed to still keep a vacuum state in the reaction tube, heat treatment at 200 ° C for 4 hours, and then in a dynamic vacuum (continuous vacuuming, keep a vacuum degree of 1.0 × 10 -2 Pa) at 200°C for 2 hours to remove TiO 2 Surface species and some generated gases, other steps are the same as in Example 1, and TiO with oxygen vacancies is obtained 2 (denoted as TiO 2 -200). Depend on Figure 1-7 It can be seen that the obtained TiO 2 There is a disordered layer on the surface of -200, and it is confirmed that the surface disordered layer is disordered TiO by dark field TEM with elemental analysis 2 , rather than condensed carbon deposits or polymer chains from surface organic species.

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Abstract

The invention discloses a method for forming oxygen vacancies of a metal oxide through oxygen-free catalysis combustion of dichloromethane. The method comprises the following steps: firstly, performing thermal treatment on a metal oxide in dynamic vacuum at 300-500 DEG C so as to remove adsorbed water; further adding dichloromethane, and performing standing adsorption; and after unadsorbed dichloromethane is removed through dynamic vacuum treatment at a normal temperature, performing oxygen-free catalysis combustion at 50-250 DEG C, and finally performing dynamic vacuum treatment so as to remove surface adsorption substances and generated gases, so as to obtain a metal oxide with oxygen vacancies, wherein the whole operation is implemented in an anhydrous oxygen-free environment. By adopting the method, CH2Cl2 which is easy to volatilize is adopted as a reactant, a simple oxygen-free catalysis combustion method is implemented, and the concentration of the oxygen vacancies on the metaloxide and the ratio of surface / bulk-phase oxygen vacancies are controlled by controlling treatment temperatures. The method is generally applicable to establishment of oxygen vacancies on other multiple metal oxides, for example, oxygen vacancies can be established on TiO2, MoO3, WO3 and ZnO by using the method.

Description

technical field [0001] The invention belongs to the technical field of preparation of photocatalysts for water splitting driven by solar energy, and in particular relates to a preparation method of metal oxide photocatalysts with oxygen vacancies. Background technique [0002] As an effective photocatalyst modification strategy, semiconductor defect engineering has been widely used to enhance the solar light harvesting ability and the quantum efficiency of solar-driven water splitting. Defects (vacancies, dislocations, interstitial atoms, etc.) in semiconductor photocatalysts can tune their physical and chemical properties in terms of electronic properties, optical properties, reactivity, surface properties, etc. Oxygen vacancies, one of the most important and ubiquitous defects for the most commonly used photocatalyst metal oxide semiconductors, have been extensively studied through experimental characterization and theoretical calculations. Studies have shown that oxygen ...

Claims

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Application Information

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IPC IPC(8): B01J21/06B01J23/06B01J23/28B01J23/30C01B3/04
CPCB01J21/063B01J23/28B01J23/30B01J23/06C01B3/042C01B2203/0277C01B2203/1076B01J35/39Y02E60/36
Inventor 顾泉刘建妮张素芬高子伟
Owner SHAANXI NORMAL UNIV