Method for preparing TiO2/g-C3N4 composite photocatalyst at low temperature

A C3N4, g-c3n4 technology, applied in the field of photocatalytic materials, can solve the problems of high photogenerated electron-hole recombination efficiency, low visible light catalytic activity, and high production cost, so as to improve the hydrogen production performance of photocatalytic water splitting and enhance the separation efficiency , low-cost effect

Active Publication Date: 2015-07-29
HEBEI UNIVERSITY OF SCIENCE AND TECHNOLOGY
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  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in practical applications, nano-TiO 2 There are still two major defects: one is the low catalytic activity of visible light, such as the commonly used anatase TiO 2 The forbidden band width is 3.2eV, and it can only absorb ultraviolet light below λ2 The photoresponse range promotes the separation of photogenerated carriers and prolongs the lifetime of carriers, thereby effectively improving the TiO 2 quantum efficiency
Prior art for TiO 2 with g-C 3 N 4 When compounding, an organic titanium source is usually used as a raw material, the reaction needs to be carried out in an organic medium, and subsequent high-temperature calcination is required, and the production cost is relatively high

Method used

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  • Method for preparing TiO2/g-C3N4 composite photocatalyst at low temperature
  • Method for preparing TiO2/g-C3N4 composite photocatalyst at low temperature
  • Method for preparing TiO2/g-C3N4 composite photocatalyst at low temperature

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] (1) Take 5g of melamine and place it in a crucible, heat it in a muffle furnace with 10 o C / min heating rate increased to 550 o C was calcined for 4h, and g-C was obtained after cooling and grinding 3 N 4 Powder; add 1g of g-C 3 N 4 The matrix was added to a mixed solution of 25 mL hydrogen peroxide and ammonia water (the volume ratio of the two was 24:1), and the suspension was obtained after ultrasonic treatment for 30 minutes;

[0023] (2) Under an ice-water bath, measure 10 mL of 30 wt% H 2 o 2 and 0.8 mL of 28wt% concentrated NH 3 . h 2 O was placed in a round bottom flask; weighed 0.245 gH 2 TiO 3 Add it into the above-mentioned round bottom flask, stir for 30 minutes to obtain a yellow-green solution; mix this solution with the suspension obtained in step (1), and stir for 2 hours to obtain a suspension;

[0024] (3) Transfer the suspension obtained in step (2) into a stainless steel reaction kettle, react for 6 hours, and the reaction temperature is 1...

Embodiment 2

[0028] (1) Take 5g of dicyandiamide and place it in a crucible, o C / min heating rate increased to 550 o C was calcined for 4h, and g-C was obtained after cooling and grinding 3 N4 matrix, 1 g of g-C 3 N 4 The matrix was added to a mixed solution of 25 mL hydrogen peroxide and ammonia water (the volume ratio of the two was 24:1), and the suspension was obtained after ultrasonic treatment for 30 minutes;

[0029] (2) Other preparation methods are the same as in Example 1.

[0030] For the obtained finished TiO 2 / g -C 3 N 4 Composite photocatalysts were tested by X-ray diffraction (see image 3 ), it can be seen that the composite catalyst contains TiO with anatase configuration 2 and graphite phase C 3 N 4 Carry out visible light catalytic water splitting experiment according to the method of embodiment 1, the average hydrogen production rate of composite photocatalyst is 72 μ mol h -1 .

Embodiment 3

[0032] (1) g-C 3 N 4 Substrate preparation, method is with embodiment 1;

[0033] (2) Under ice water bath, measure 10mL, 30wt% H 2 o 2 and 0.5 mL28wt% concentrated ammonia water were placed in a round bottom flask, and 0.145g H was weighed 2 TiO 3 Add it into the above-mentioned round bottom flask, stir for 30 minutes to obtain a yellow-green solution; mix the yellow-green solution with the suspension obtained in step (1), and stir for 2 hours to obtain a suspension;

[0034] (3) Transfer the suspension obtained in step (2) into a stainless steel reaction kettle, react for 6 hours, and the reaction temperature is 160°C to obtain the product;

[0035] (4) Filter, wash, and dry the product obtained in step (3); the dried solid is calcined in a muffle furnace at 250°C to obtain the finished TiO 2 / g -C 3 N 4 Composite photocatalyst finished product.

[0036] For the obtained finished TiO 2 / g -C 3 N 4 Composite photocatalysts were tested by X-ray diffraction (see fi...

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Abstract

The invention discloses a method for preparing a TiO2 / g-C3N4 composite photocatalyst at a low temperature. The method comprises the following steps: (1) adding g-C3N4 powder in a mixed solution of hydrogen peroxide and ammonium hydroxide, and performing ultrasonic treatment to obtain turbid liquid A; (2) in an ice-water bath, mixing and stirring metatitanic acid, stronger ammonia water and hydrogen peroxide to obtain a yellow-green solution B, and mixing and stirring the yellow-green solution B with the turbid liquid A obtained in the step (1) to obtain turbid liquid C; (3) transferring the turbid liquid C obtained in the step (2) in a stainless steel reaction kettle, and performing hydrothermal reaction to obtain a product D; (4) filtering, washing and drying the product D obtained in the step (3), and calcining the dried solid at a low temperature to obtain a finished product. According to the invention, after TiO2 is compounded on the surface of g-C3N4, the photo-generated electron-hole pairs of g-C3N4 can be effectively separated, and the hydrogen production efficiency of g-C3N4 is improved. The method is simple, low in cost and small in pollution, and can meet the practical production demands.

Description

technical field [0001] The invention relates to a method for preparing a catalyst, in particular to a method for preparing TiO at low temperature 2 / g -C 3 N 4 A composite photocatalyst method belongs to the technical field of photocatalytic materials. Background technique [0002] TiO 2 The material is odorless, non-toxic, and has high light stability, thermal stability and chemical stability. It is considered to be the most environmentally friendly material with development prospects and application potential. Therefore, it is used in water pollution treatment, photolysis of water to produce hydrogen, and solar cells. Various fields have been extensively studied. However, in practical applications, nano-TiO 2 There are still two major defects: one is the low catalytic activity of visible light, such as the commonly used anatase TiO 2 The forbidden band width is 3.2eV, and it can only absorb ultraviolet light below λ<387nm, and this part of light only accounts for ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J27/24C01B3/04
CPCY02E60/36
Inventor 王晓静杨文琰李发堂
Owner HEBEI UNIVERSITY OF SCIENCE AND TECHNOLOGY
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