阅读说明：本技术 一种黑色钨酸铋光催化剂及制备方法和应用 (Black bismuth tungstate photocatalyst as well as preparation method and application thereof ) 是由 许晖 朱兴旺 李启笛 储金宇 杜彦生 杨金曼 于 2019-09-17 设计创作，主要内容包括：本发明涉及一种黑色钨酸铋光催化剂及制备方法和应用,属于光催化材料的制备方法技术领域,具体应用方向为光催化CO<Sub>2</Sub>还原。本发明利用介质阻挡放电,在不同气氛下产生等离子体,对白色钨酸铋进行处理,得到黑色钨酸铋光催化剂,等离子体处理使得钨酸铋表面还原出铋单质,促进了光生空穴和电子的分离,同时拓宽了光吸收范围,提高了光催化CO<Sub>2</Sub>还原能力。(The invention relates to a black bismuth tungstate photocatalyst, a preparation method and application thereof, belongs to the technical field of preparation methods of photocatalytic materials, and particularly relates to a method for preparing a black bismuth tungstate photocatalyst by photocatalysis of CO 2 And (4) reducing. According to the invention, dielectric barrier discharge is utilized to generate plasmas under different atmospheres, white bismuth tungstate is treated to obtain black bismuth tungstate photocatalyst, the bismuth elementary substance is reduced on the surface of the bismuth tungstate by the plasma treatment, the separation of photoproduction holes and electrons is promoted, the light absorption range is widened, and the photocatalysis CO is improved 2 Reducing power.)

1. A preparation method of black bismuth tungstate photocatalyst is characterized in that medium barrier discharge is utilized to generate plasmas under different atmospheres, white bismuth tungstate is treated to obtain black tungstenThe bismuth tungstate photocatalyst is treated by plasma to reduce bismuth simple substance on the surface of the bismuth tungstate, promote the separation of photoproduction holes and electrons, widen the light absorption range and improve the photocatalysis CO₂The reduction capacity comprises the following specific steps:

(1) weighing white bismuth tungstate and absolute ethyl alcohol, performing ultrasonic dispersion to form a uniform mixture, uniformly coating the mixture on a quartz plate, and then drying;

(2) placing the dried quartz plate with the white bismuth tungstate into a dielectric barrier discharge reactor, carrying out plasma discharge treatment at certain power and time, and introducing reaction gas at a constant speed in the treatment process;

(3) collecting the bismuth tungstate subjected to the first plasma treatment, performing ultrasonic dispersion again by using absolute ethyl alcohol to form a uniform mixture, uniformly coating the mixture on a quartz plate, and then drying;

(4) and (3) placing the completely dried quartz piece with the bismuth tungstate into a dielectric barrier discharge reactor for secondary treatment, introducing reaction gas at a constant speed in the treatment process, and finally obtaining the black bismuth tungstate photocatalytic material after the treatment is finished.

2. The method for preparing a black bismuth tungstate photocatalyst as claimed in claim 1, wherein in the step (1), the amount of the white bismuth tungstate is 5-20 mg; the dosage of the absolute ethyl alcohol is 2-4 mL; the ultrasonic power is 100-150W, and the ultrasonic time is 5-10 min; the thickness of the quartz plate used was 0.5 mm.

3. The method for preparing a black bismuth tungstate photocatalyst as claimed in claim 1, wherein in the step (2), the dielectric barrier discharge power is 50-100W; the reaction gas is argon, ammonia or hydrogen, the treatment time is 1-5min, and the gas flow is 100-200 mL/min.

4. The method for preparing a black bismuth tungstate photocatalyst as claimed in claim 1, wherein in the step (3), the amount of the absolute ethyl alcohol is 1-2 mL; the ultrasonic power is 50-100W, and the ultrasonic time is 3-5 min; the thickness of the quartz plate used was 0.5 mm.

5. The method for preparing a black bismuth tungstate photocatalyst as claimed in claim 1, wherein in the step (4), the dielectric barrier discharge power, the treatment time and the gas flow rate are changed, and the dielectric barrier discharge power is 100-150W; the reaction gas is argon, ammonia or hydrogen, the treatment time is 5-15min, and the gas flow is 200-300 mL/min.

Technical Field

The invention relates to a preparation method of a black bismuth tungstate photocatalyst, belongs to the technical field of preparation methods of photocatalytic materials, and particularly relates to a method for preparing a black bismuth tungstate photocatalyst by photocatalysis of CO₂And (4) reducing.

Background

Bismuth tungstate (Bi)₂WO₆) As a photocatalyst with certain visible light response in organic pollutantsDegradation of dyestuffs and CO₂The aspects of reduction and the like are widely researched and applied. But the traditional bismuth tungstate catalyst has high carrier recombination rate, so that the photocatalytic efficiency of the bismuth tungstate catalyst is influenced. Therefore, it is becoming more and more important to modify the traditional bismuth tungstate catalyst to improve the photocatalytic efficiency. The existing photocatalyst modification method mainly comprises appearance regulation, precious metal deposition, semiconductor compounding, defect regulation and the like. The surface modification of the photocatalyst by plasma has been developed in recent years to greatly improve the catalytic performance.

Plasma refers to a partially or completely ionized gas, and the sum of the positive and negative charges of free electrons and ions is completely cancelled out, and the plasma is macroscopically electrically neutral. It can be divided into high-temperature plasma (thermonuclear fusion plasma) and low-temperature plasma according to the temperature of the plasma. Low temperature plasmas also include thermal plasmas (plasma arcs, torches, etc.) and cold plasmas (low pressure ac/dc, radio frequency, microwave plasmas as well as high pressure dielectric barrier discharge, corona discharge, RF discharge, etc.). The low-temperature cold plasma has a large amount of active particles which can react with the surface of a contacted material, so that the active particles are used for modifying the surface of the material.

Dielectric Barrier Discharge (DBD) is a non-equilibrium gas discharge with an insulating dielectric inserted into a discharge space, which is also called dielectric barrier corona discharge or silent discharge. Dielectric barrier discharges are capable of operating at high gas pressures and over a wide frequency range, typically capable of generating plasma at atmospheric pressure, with power supply frequencies ranging from 50Hz to 1 mhz. The dielectric barrier discharge plasma treatment photocatalyst has the characteristics of mild treatment conditions, short reaction time, low energy consumption and the like.

Disclosure of Invention

The invention aims to overcome the defect of low utilization rate of visible light of the traditional bismuth tungstate photocatalytic material, utilizes dielectric barrier discharge to generate plasmas under different atmospheres, processes white bismuth tungstate to obtain a black bismuth tungstate photocatalyst, reduces a bismuth simple substance on the surface of the bismuth tungstate by the plasma treatment, promotes the separation of photoproduction holes and electrons, widens the light absorption range, and improves the photocatalysisTo convert CO₂Reducing power.

In order to realize the purpose of the invention, the following technical scheme is mainly adopted:

a preparation method of a black bismuth tungstate photocatalyst comprises the following steps:

(1) weighing white bismuth tungstate and absolute ethyl alcohol, performing ultrasonic dispersion to form a uniform mixture, uniformly coating the mixture on a quartz plate, and then drying;

(2) placing the dried quartz plate with the white bismuth tungstate into a dielectric barrier discharge reactor, carrying out plasma discharge treatment at certain power and time, and introducing reaction gas at a constant speed in the treatment process;

(3) collecting the bismuth tungstate subjected to the first plasma treatment, performing ultrasonic dispersion again by using absolute ethyl alcohol to form a uniform mixture, uniformly coating the mixture on a quartz plate, and then drying;

(4) and (3) placing the completely dried quartz piece with the bismuth tungstate into a dielectric barrier discharge reactor for secondary treatment, introducing reaction gas at a constant speed in the treatment process, and finally obtaining the black bismuth tungstate photocatalytic material after the treatment is finished.

The preparation method comprises the following steps: in the step (1), the dosage of the white bismuth tungstate is 5-20 mg; the dosage of the absolute ethyl alcohol is 2-4 mL; the ultrasonic power is 100-150W, and the ultrasonic time is 5-10 min; the thickness of the quartz plate used was 0.5 mm.

The preparation method comprises the following steps: in the step (2), the dielectric barrier discharge power is 50-100W; the reaction gas is argon, ammonia or hydrogen, the treatment time is 1-5min, and the gas flow is 100-200 mL/min.

The preparation method comprises the following steps: in the step (3), the dosage of the absolute ethyl alcohol is 1-2 mL; the ultrasonic power is 50-100W, and the ultrasonic time is 3-5 min; the thickness of the quartz plate used was 0.5 mm.

The preparation method comprises the following steps: in the step (4), dielectric barrier discharge power, processing time and gas flow are changed, wherein the dielectric barrier discharge power is 100-; the reaction gas is argon, ammonia or hydrogen, the treatment time is 5-15min, and the gas flow is 200-300 mL/min.

The black bismuth tungstate photocatalytic material is prepared by the method.

The invention has the beneficial effects that:

the invention adopts the dielectric barrier discharge plasma processing method, has the characteristics of mild processing conditions, short reaction time, low energy consumption and environmental friendliness, is suitable for mass production and has certain application prospect.

The black bismuth tungstate photocatalyst prepared by the invention contains bismuth simple substance on the surface, promotes the separation of photoproduction holes and electrons, has higher visible light absorption and can be used for photocatalysis of CO₂Has a certain application prospect in the reduction aspect.

Drawings

FIG. 1 is a color comparison graph of bismuth tungstate before and after plasma treatment in example 1.

FIG. 2 is an XRD spectrum of bismuth tungstate before and after plasma treatment in example 1.

FIG. 3 is a UV-VIS diffuse reflectance spectrum of bismuth tungstate before and after plasma treatment in example 1.

FIG. 4 is CO of bismuth tungstate before and after plasma treatment in example 1₂Reduction activity is compared with the figure.

Detailed Description

The invention is described in detail below with reference to specific embodiments, but the invention is not limited thereto

The experimental procedures used in the following examples are conventional unless otherwise specified.

Materials, reagents and the like used in the following examples are commercially available unless otherwise specified.