CoWO (cobalt oxide tungsten trioxide)4/Bi2WO6Composite acoustic catalyst and preparation method and application thereof
阅读说明：本技术 一种CoWO4/Bi2WO6复合声催化剂及其制备方法和应用 (CoWO (cobalt oxide tungsten trioxide)4/Bi2WO6Composite acoustic catalyst and preparation method and application thereof ) 是由 王思幻 徐亮 刘妮萍 吴学签 张琳 王新 于 2021-09-15 设计创作，主要内容包括：本发明公开一种CoWO-(4)/Bi-(2)WO-(6)复合声催化剂及其制备方法和应用。将Bi(NO-(3))-(3)·5H-(2)O溶解在HNO-(3)中,充分搅拌后,所得溶液缓慢滴加到CoWO-(4)水溶液中,得溶液A；将Na-(2)WO-(4)·2H-(2)O溶解在NaOH中,得溶液B；将溶液A缓慢滴加到溶液B中,持续搅拌后,将所得混合溶液转移到高压釜中,进行水热反应；抽滤,洗涤,干燥,得CoWO-(4)/Bi-(2)WO-(6)复合声催化剂。Bi-(2)WO-(6)具有独特的花状层次结构,具有较大的比表面积,为纳米粒子在片状上的定向高密度和均匀生长提供了结构框架。复合后的声催化剂极大的改善了声催化活性,在环境净化领域具有较强的实用价值。(The invention discloses a CoWO 4 /Bi 2 WO 6 A composite acoustic catalyst, a preparation method and application thereof. Adding Bi (NO) 3 ) 3 ·5H 2 Dissolving O in HNO 3 After sufficiently stirring, the resulting solution was slowly added dropwise to CoWO 4 Obtaining solution A in the aqueous solution; mixing Na 2 WO 4 ·2H 2 Dissolving O in NaOH to obtain solution B; slowly dropwise adding the solution A into the solution B, continuously stirring, transferring the obtained mixed solution into a high-pressure kettle, and carrying out hydrothermal reaction; filtering, washing and drying to obtain CoWO 4 /Bi 2 WO 6 A composite acoustic catalyst. Bi 2 WO 6 Has a unique flower-like hierarchical structure and larger specific surface area, and provides a structural framework for the directional high-density and uniform growth of the nano particles on the sheet shape. The acoustic catalyst after being compounded greatly improves the acoustic catalytic activity and has stronger practical value in the field of environmental purification.)
1. CoWO (cobalt oxide tungsten trioxide)4/Bi2WO6The preparation method of the composite acoustic catalyst is characterized by comprising the following steps:
1) taking CoWO4Dispersing the powder in deionized water to obtain CoWO4An aqueous solution;
2) adding Bi (NO)3)3·5H2Dissolving O in HNO3After sufficiently stirring, the resulting solution was slowly added dropwise to CoWO4Obtaining solution A in the aqueous solution;
3) mixing Na2WO4·2H2Dissolving O in NaOH to obtain solution B;
4) slowly dropwise adding the solution A into the solution B, continuously stirring, transferring the obtained mixed solution into a high-pressure kettle, and carrying out hydrothermal reaction;
5) filtering, washing with deionized water and absolute ethyl alcohol in sequence, and drying to obtain CoWO4/Bi2WO6A composite acoustic catalyst.
2. The method of claim 1, wherein HNO is produced by a process comprising3The concentration is 1 mol.L-1。
3. The process according to claim 1, wherein the NaOH concentration is 1 mol-L-1。
4. The process according to claim 1, wherein Bi (NO) is added in a molar ratio3)3·5H2O:Na2WO4·2H2O:CoWO4＝1.8:1:1.8-20。
5. The method according to claim 1, wherein the hydrothermal reaction in step 4) is carried out at 180 ℃ for 8 hours.
6. CoWO prepared according to the process of any of claims 1 to 54/Bi2WO6The application of the composite acoustic catalyst in catalyzing and degrading organic pollutants.
7. Use according to claim 6, characterized in that the method is as follows: adding CoWO to wastewater containing organic contaminants4/Bi2WO6Composite acoustic catalyst, ultrasonic catalysis.
8. Use according to claim 7, characterized in that the concentration of organic contaminants is adjusted to 10 mg/L.
9. Use according to claim 8, characterized in that CoWO4/Bi2WO6The amount of the composite catalyst added was 1 g/L.
10. Use according to claims 7-9, wherein the organic contaminant is ofloxacin.
Technical Field
The invention belongs to the field of acoustic catalysts, and particularly relates to CoWO4/Bi2WO6A composite acoustic catalyst, a preparation method and application thereof.
Background
Cobalt tungstate (CoWO)4) As an important material in the electronic and optical fields, it is one of the simplest members of the tungstate family, and has good acoustic catalytic activity. But monomeric CoWO4The acoustic catalytic efficiency is low. Therefore, it is desired to develop a simple, economical and efficient method for increasing CoWO4The acoustic catalytic activity of (a) requires further investigation.
Disclosure of Invention
The invention aims to provide a CoWO4/Bi2WO6Composite acoustic catalyst to solve the problem of monomer CoWO4The acoustic catalysis efficiency is low.
Another object of the present invention is to provide a CoWO4/Bi2WO6A preparation method of a composite acoustic catalyst.
The technical scheme adopted by the invention is as follows: CoWO (cobalt oxide tungsten trioxide)4/Bi2WO6The preparation method of the composite acoustic catalyst comprises the following steps:
1) taking CoWO4Dispersing the powder in deionized water to obtain CoWO4An aqueous solution;
2) adding Bi (NO)3)3·5H2Dissolving O in HNO3After sufficiently stirring, the resulting solution was slowly added dropwise to CoWO4Obtaining solution A in the aqueous solution;
3) mixing Na2WO4·2H2Dissolving O in NaOH to obtain solution B;
4) slowly dropwise adding the solution A into the solution B, continuously stirring, transferring the obtained mixed solution into a high-pressure kettle, and carrying out hydrothermal reaction;
5) filtering, washing with deionized water and absolute ethyl alcohol in sequence, and drying to obtain CoWO4/Bi2WO6A composite acoustic catalyst.
Further, the above preparation method, HNO3The concentration is 1 mol.L-1。
Further, in the above production method, the NaOH concentration is 1 mol. L-1。
Further, the above-mentioned preparation method, in terms of mole ratio, of Bi (NO)3)3·5H2O:Na2WO4·2H2O:CoWO4＝1.8:1:1.8-20。
Further, in the above preparation method, step 4), the hydrothermal reaction is carried out at 180 ℃ for 8 h.
CoWO provided by the invention4/Bi2WO6The application of the composite acoustic catalyst in catalyzing and degrading organic pollutants.
Further, the method is as follows: adding CoWO to wastewater containing organic contaminants4/Bi2WO6Composite acoustic catalyst, ultrasonic catalysis.
Further, the concentration of the organic contaminant was adjusted to 10 mg/L.
Further, CoWO4/Bi2WO6The amount of the composite catalyst added was 1 g/L.
Further, the organic contaminant is ofloxacin.
Compared with the prior art, the invention has the following advantages:
1. CoWO prepared by the invention4/Bi2WO6Composite acoustic catalyst, Bi2WO6Has high activity due to the narrow band gap (2.67eV), and is prepared by adding Bi2WO6Nanosheet surface-loaded CoWO4The nanoparticles form a heterojunction structure, and can promote electricityThe separation of the carrier-hole pairs inhibits carrier recombination, allowing more time for charge to participate in subsequent acoustic catalytic reactions prior to recombination. CoWO of this structure4/Bi2WO6The composite catalyst is expected to be applied in the fields of solar energy conversion, organic matter oxidation decomposition, water purification and the like.
2. The invention consists of CoWO4，Bi(NO3)3·5H2O and Na2WO4·2H2And O reaction. Bi2WO6Has a unique flower-like hierarchical structure and larger specific surface area, and provides a structural framework for the directional high-density and uniform growth of the nano particles on the sheet shape.
3. CoWO prepared by the invention4/Bi2WO6The composite acoustic catalyst greatly improves the acoustic catalytic activity, can efficiently degrade organic pollutants, has a degradation rate of 64.77 percent in 120min under the ultrasonic condition, and has strong practical value in the field of environmental purification.
4. The preparation method of the invention adopts a hydrothermal synthesis method, and has the advantages of simple process, short synthesis time and higher yield.
Drawings
FIG. 1 is a CoWO prepared in example 14/Bi2WO6XRD pattern of the composite acoustic catalyst.
FIG. 2 is a CoWO prepared in example 14/Bi2WO6XPS plot of composite acoustic catalyst.
FIG. 3 is a CoWO prepared in examples 1-44/Bi2WO6And (3) comparing the degradation rate of the compound acoustic catalyst to the ofloxacin solution.
Detailed Description
Example 1 CoWO4/Bi2WO6Composite acoustic catalyst
The preparation method comprises
1、CoWO4Preparation of
According to the molar ratio of 1:1, 0.5mmol of Co (NO)3)2·6H2O and 0.5mmol Na2WO4·2H2O is put in and filled withIn a conical flask with 30mL of deionized water, magnetically stirring for 30min, pouring into a polytetrafluoroethylene reaction kettle, and placing into a forced air drying oven for reaction at 180 ℃ for 24 h; filtering after the reaction is finished, drying for 2h at 80 ℃, grinding into fine powder by using an agate mortar to obtain CoWO4And (3) powder.
2、CoWO4/Bi2WO6Preparation of composite acoustic catalyst
Taking CoWO4Powder (200mg, 0.65mmol) and dispersed in 30mL deionized water to give CoWO4An aqueous solution.
Adding Bi (NO)3)3·5H2O (315.2mg, 0.65mmol) was dissolved in 20mL of 1 mol. L-1HNO of (2)3After magnetic stirring, the resulting solution was slowly added dropwise to CoWO4In the aqueous solution, solution A was obtained.
Mixing Na2WO4·2H2O (106.8mg, 0.36mmol) was dissolved in 20mL of 1 mol. L-1NaOH to give solution B.
The solution A is slowly dripped into the solution B, and after continuous stirring, the obtained mixed solution is transferred into an autoclave and undergoes hydrothermal reaction in an oven at 180 ℃ for 8 hours.
Filtering, washing with deionized water and anhydrous ethanol for several times, and drying at 60 deg.C for 2 hr to obtain Bi3 +:Co2+1:1 CoWO4/Bi2WO6A composite acoustic catalyst.
(II) characterization analysis
Synthesis of CoWO Using X-ray powder diffraction (XRD) technique4/Bi2WO6The nanocomposite was subjected to phase purity and structural analysis, and the obtained spectrum was as shown in fig. 1. The XRD pattern of the clean continuous wave sample showed high crystallinity due to the presence of sharp, narrow and strong diffraction peaks, consistent with the standard structure (JCPDS No. 72-0479).
FIG. 2 analyzes CoWO4And CoWO4/Bi2WO6The samples can clearly see signals of O, Co, Bi and W elements in the spectrum of the samples, and the synthesized products are all composed of the four elements.
Example 2 CoWO4/Bi2WO6Preparation of composite acoustic catalyst
Taking CoWO4Powder (200mg, 0.65mmol) and dispersed in 30mL deionized water to give CoWO4An aqueous solution.
Adding Bi (NO)3)3·5H2O (157.6mg, 0.325mmol) was dissolved in 20mL of 1 mol. L-1HNO of (2)3After magnetic stirring, the resulting solution was slowly added dropwise to CoWO4In the aqueous solution, solution A was obtained.
Mixing Na2WO4·2H2O (53.4mg, 0.18mmol) was dissolved in 20mL of 1 mol. L-1NaOH to give solution B.
The solution A is slowly dripped into the solution B, and after continuous stirring, the obtained mixed solution is transferred into an autoclave and undergoes hydrothermal reaction in an oven at 180 ℃ for 8 hours.
Filtering, washing with deionized water and anhydrous ethanol for several times, and drying at 60 deg.C for 2 hr to obtain Bi3 +:Co2+1:2 CoWO4/Bi2WO6A composite acoustic catalyst.
Example 3 CoWO4/Bi2WO6Preparation of composite acoustic catalyst
Taking CoWO4Powder (200mg, 0.65mmol) and dispersed in 30mL deionized water to give CoWO4An aqueous solution.
Adding Bi (NO)3)3·5H2O (78.8mg, 0.163mmol) was dissolved in 20mL of 1 mol. L-1HNO of (2)3After magnetic stirring, the resulting solution was slowly added dropwise to CoWO4In the aqueous solution, solution A was obtained.
Mixing Na2WO4·2H2O (26.7mg, 0.09mmol) was dissolved in 20mL of 1 mol. L-1NaOH to give solution B.
The solution A is slowly dripped into the solution B, and after continuous stirring, the obtained mixed solution is transferred into an autoclave and undergoes hydrothermal reaction in an oven at 180 ℃ for 8 hours.
Filtering, washing with deionized water and anhydrous ethanol for several times, and drying at 60 deg.C for 2 hr to obtain Bi3 +:Co2+1:4 CoWO4/Bi2WO6A composite acoustic catalyst.
Example 4 CoWO4/Bi2WO6Preparation of composite acoustic catalyst
Taking CoWO4Powder (200mg, 0.65mmol) and dispersed in 30mL deionized water to give CoWO4An aqueous solution.
Adding Bi (NO)3)3·5H2O (31.52mg, 0.065mmol) was dissolved in 20mL of 1 mol. L-1HNO of (2)3After magnetic stirring, the resulting solution was slowly added dropwise to CoWO4In the aqueous solution, solution A was obtained.
Mixing Na2WO4·2H2O (10.68mg, 0.036mmol) was dissolved in 20mL of 1 mol. L-1NaOH to give solution B.
The solution A is slowly dripped into the solution B, and after continuous stirring, the obtained mixed solution is transferred into an autoclave and undergoes hydrothermal reaction in an oven at 180 ℃ for 8 hours.
Filtering, washing with deionized water and anhydrous ethanol for several times, and drying at 60 deg.C for 2 hr to obtain Bi3 +:Co2+1:10 CoWO4/Bi2WO6A composite acoustic catalyst.
Example 5 CoWO4/Bi2WO6Composite acoustic catalyst for degrading ofloxacin
The method comprises the following steps: separately weighing CoWO4And CoWO prepared in examples 1 to 44/Bi2WO620mg of each composite acoustic catalyst is added with 20mL of ofloxacin solution with the concentration of 10mg/L, and the ultrasonic catalysis is carried out for 2h, the ultrasonic power is 200W, and the ultrasonic temperature is 20 ℃. Sampling the treated suspension, centrifuging, taking the supernatant, measuring the UV-vis spectrum of the supernatant in the range of 200-400nm, and determining the degradation rate of the ofloxacin solution by using the solution at the lambda of the solutionmaxCalculated as the absorbance at 291nm,
the formula is that the percent (%) degradation is [ (A)0-At)/A0]×100％
A0Is the initial absorbance of ofloxacin
AtIs the absorbance of ofloxacin at various times
The results are shown in FIG. 3, and show that CoWO is produced4/Bi2WO6Composite acoustic catalyst to CoWO alone4The acoustic catalytic activity is higher. The catalyst prepared in example 1 had a degradation rate of 64.77%.
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