Preparation method of nano ZnO-SnO2 composite oxide photo-catalyst

Abstract

The preparation method of nano ZnO-SnO2 composite oxide photocatalyst uses water soluble zinc salt and SnCl4.5H2O as raw material, uses ammonia water as precipitant, and utilizes the characteristics of that the amine salt formed by combining ammonia water with negative ion being in other solution can be decomposed into gas to escape when it is sintered and has no need of longer-time washing process so as to can obtain the invented catalyst with higher activity. Said catalyst can degrate and pollutant into harmless compound.

Description

technical field

[0001] The invention relates to a nanometer ZnO-SnO 2 Preparation method of composite oxide photocatalyst. technical background

[0002] In the study of photocatalytic degradation, since the photocatalytic performance of semiconductor photocatalysts has a great relationship with the number and lifetime of photogenerated carriers (electron / hole pairs) of photocatalysts, the larger the number, the longer the lifetime, and the photocatalytic performance the better. However, the photogenerated carriers can be in 10 -9 Therefore, one of the key problems in improving photocatalytic activity is how to reduce the recombination probability of photogenerated electrons and holes.

[0003] The recombination of two semiconductors with different bandgap widths can enhance charge separation, suppress electron-hole recombination and extend the photoexcitation wavelength range, thus showing better stability and photocatalytic activity than single semiconductors.

[0004] ...

Examples

Embodiment 1

[0021] Weigh 1437.8g of analytically pure ZnSO at a molar ratio of 20:1 4 ·7H 2 O dissolved in 4000mL deionized water, 87.8g analytically pure SnCl 4 ·5H 2 O was dissolved in 400mL of deionized water, mixed thoroughly after dissolving, and analytically pure NH was added dropwise under vigorous stirring. 3 ·H 2 O solution until the pH was 7 and continued to stir for 12 hours to obtain a gel. After filtration under reduced pressure, bake at 110°C for 24 hours to dry to obtain xerogel. After fully grinding, slowly heat up to 350°C in a high-temperature box-type resistance furnace for calcination for 2 hours to obtain a specific surface area of ​​17.6m 2 / g ZnO-SnO 2 Composite oxide photocatalyst, the degradation rate of organic matter is 54.66%.

Embodiment 2

[0023] Weigh 71.89g of analytically pure ZnSO at a molar ratio of 1:20 4 ·7H 2 O dissolved in 300mL deionized water, 1752.9g analytically pure SnCl 4 ·5H 2 O was dissolved in 7000mL of deionized water, mixed thoroughly after dissolution, and analytically pure NH was added dropwise under vigorous stirring. 3 ·H 2 O solution until pH 7 and continued stirring for 12 hours to obtain a gel. After filtration under reduced pressure, bake at 110°C for 24 hours to dry to obtain xerogel. After fully grinding, slowly heat up to 350°C in a high-temperature box-type resistance furnace for calcination for 2 hours to obtain a specific surface area of ​​43.6m 2 / g ZnO-SnO 2 Composite oxide photocatalyst, the degradation rate of organic matter is 21.79%.

Embodiment 3

[0025] Weigh 143.8g of analytically pure ZnSO at a molar ratio of 2:1 4 ·7H 2 O dissolved in 400 mL of deionized water, 87.8 g of analytically pure SnCl 4 ·5H 2 O was dissolved in 400mL of deionized water, mixed thoroughly after dissolving, and analytically pure NH was added dropwise under vigorous stirring. 3 ·H 2 O solution until pH 7 and continued stirring for 12 hours to obtain a gel. After filtration under reduced pressure, bake at 110°C for 24 hours to dry to obtain a xerogel. After fully grinding, slowly heat up to 300°C in a high-temperature box-type resistance furnace for calcination for 2 hours to obtain ZnO with a size of 1.7nm and SnO 2 0.8nm powder.

technical field

[0001] The invention relates to a nanometer ZnO-SnO 2 Preparation method of composite oxide photocatalyst. technical background

[0002] In the study of photocatalytic degradation, since the photocatalytic performance of semiconductor photocatalysts has a great relationship with the number and lifetime of photogenerated carriers (electron / hole pairs) of photocatalysts, the larger the number, the longer the lifetime, and the photocatalytic performance the better. However, the photogenerated carriers can be in 10 -9 Therefore, one of the key problems in improving photocatalytic activity is how to reduce the recombination probability of photogenerated electrons and holes.

[0003] The recombination of two semiconductors with different bandgap widths can enhance charge separation, suppress electron-hole recombination and extend the photoexcitation wavelength range, thus showing better stability and photocatalytic activity than single semiconductors.

[0004] ...

Examples

Embodiment 1

[0021] Weigh 1437.8g of analytically pure ZnSO at a molar ratio of 20:1 4 ·7H 2 O dissolved in 4000mL deionized water, 87.8g analytically pure SnCl 4 ·5H 2 O was dissolved in 400mL of deionized water, mixed thoroughly after dissolving, and analytically pure NH was added dropwise under vigorous stirring. 3 ·H 2 O solution until the pH was 7 and continued to stir for 12 hours to obtain a gel. After filtration under reduced pressure, bake at 110°C for 24 hours to dry to obtain xerogel. After fully grinding, slowly heat up to 350°C in a high-temperature box-type resistance furnace for calcination for 2 hours to obtain a specific surface area of ​​17.6m 2 / g ZnO-SnO 2 Composite oxide photocatalyst, the degradation rate of organic matter is 54.66%.

Embodiment 2

[0023] Weigh 71.89g of analytically pure ZnSO at a molar ratio of 1:20 4 ·7H 2 O dissolved in 300mL deionized water, 1752.9g analytically pure SnCl 4 ·5H 2 O was dissolved in 7000mL of deionized water, mixed thoroughly after dissolution, and analytically pure NH was added dropwise under vigorous stirring. 3 ·H 2 O solution until pH 7 and continued stirring for 12 hours to obtain a gel. After filtration under reduced pressure, bake at 110°C for 24 hours to dry to obtain xerogel. After fully grinding, slowly heat up to 350°C in a high-temperature box-type resistance furnace for calcination for 2 hours to obtain a specific surface area of ​​43.6m 2 / g ZnO-SnO 2 Composite oxide photocatalyst, the degradation rate of organic matter is 21.79%.

Embodiment 3

[0025] Weigh 143.8g of analytically pure ZnSO at a molar ratio of 2:1 4 ·7H 2 O dissolved in 400 mL of deionized water, 87.8 g of analytically pure SnCl 4 ·5H 2 O was dissolved in 400mL of deionized water, mixed thoroughly after dissolving, and analytically pure NH was added dropwise under vigorous stirring. 3 ·H 2 O solution until pH 7 and continued stirring for 12 hours to obtain a gel. After filtration under reduced pressure, bake at 110°C for 24 hours to dry to obtain a xerogel. After fully grinding, slowly heat up to 300°C in a high-temperature box-type resistance furnace for calcination for 2 hours to obtain ZnO with a size of 1.7nm and SnO 2 0.8nm powder.

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