Preparation method for heterojunction photocatalyst and application

Abstract

The invention belongs to the technical field of semiconductor material preparation and especially relates to a preparation method for a heterojunction photocatalyst and an application. The method comprises the following steps: weighing manganese tungstate, bismuth nitrate and potassium bromide; dissolving in a mixed solvent of glycol and deionized water; ultrasonically dissolving, thereby acquiring a precursor suspension; transferring into a hydrothermal reaction kettle; reacting in an oven; washing with water, filtering and drying, thereby acquiring a MnWO4/BiOBr heterojunction material. The MnWO4/BiOBr heterojunction photocatalyst is prepared according to a hydrothermal method and a solvent thermal method in the manner of regulating different mole ratios of added manganese tungstate to bismuth nitrate to potassium bromide; the degrading effects to the organic pollutants (rhodamine b and tetracycline) (10mg/L) under the irradiation of visible light under the condition of same catalyst dosage (50mg) are respectively observed; a photo-catalytic result shows that the MnWO4/BiOBr heterojunction photocatalyst prepared by compounding less manganese tungstate and bismuthyl bromide can obviously promote the photo-catalytic activity.

Description

technical field [0001] The invention belongs to the technical field of semiconductor material preparation, and utilizes a hydrothermal method and a solvothermal method to synthesize manganese tungstate and bismuth oxybromide heterojunction photocatalyst, which can be used to degrade organic pollutants (rhodamine B and tetracycline) under visible light. Background technique [0002] In recent years, semiconductor photocatalytic technology has been extensively studied due to its advantages of high efficiency, energy saving, and thorough pollutant degradation. Since it can degrade and eliminate organic wastewater by utilizing solar energy to the greatest extent, it is considered to be an ideal way to solve water pollution. This technology uses semiconductor photocatalysts to generate photogenerated electrons-holes with high redox ability under the irradiation of a specific light source to achieve efficient degradation and elimination of organic pollutants. It is obtained due to ...

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Problems solved by technology

[0002] In recent years, semiconductor photocatalytic technology has been extensively studied due to its advantages of high efficiency, energy saving, and thorough pollutant degradation. Since it can degrade and eliminate organic wastewater by utilizing solar energy to the greatest extent, it is considered to be an ideal way to solve water pollution. This technology uses semiconductor photocatalysts to generate photogenerated electrons-holes with high redox ability under the irradiation of a specific light source to achieve efficient degradation and elimination of organic pollutants. It is obtained due to its advantages of high degradation efficiency, short cycle and low cost. For a wide range of applications, currently the most studied semiconductor photocatalysts, such as: TiO 2 、BiPO 4 Ultraviolet light response materials (ultraviolet light only accounts for about 5% of the solar spectrum), due to the low efficiency of solar energy utilization, has largely limited the development of semiconductor photocatalysis technology. Therefore, the development of new and efficient visible light responsive semiconductor light Catalyst is a hot spot in the field of photocatalysis research

[0003] Manganese tungstate (MnWO 4 ) as a semiconductor material with visible light response has attracted the attention of researchers in the photocatalytic degradation of organic pollutants due to its good chemical stability and suitable bandgap energy (about 2.6eV). However, a single wxya 4 Due to the material's weak absorption of visible light and the easy recombination of photogenerated electron-hole pairs generated under illumination, MnWO 4 The photocatalytic degradation effect on organic pollutants is not ideal, so the construction based on MnWO 4 It is crucial to promote the separation of photogenerated electron-hole pairs and enhance the photocatalytic degradation performance in heterojunction photocatalytic systems.

[0004] Bismuth oxybromide (BiOBr), as a Bi-semiconductor material with a layered structure, has a bandgap width of about 2.7eV. Due to its high chemical stability and photocatalytic activity, it has been widely used in the efficient degradation of organic wastewater. However, the degradation efficiency of a single BiOBr material to organic pollutants is not high, mainly because the photogenerated electron-hole pairs generated by BiOBr under the excitation of visible light are very easy to recombine, resulting in low photocatalytic degradation performance. At present, the construction of BiOBr-based The heterojunction photocatalytic system is an effective means to improve the photocatalytic performance, such as: CdS / BiOBr, Cu 2 O / BiOBr and g-C 3 N 4 / BiOBr etc.

[0005] But so far, no MnWO has been found 4 Composite with BiOBr to form a heterojunction and its photocatalytic application report

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