A carbon cloth-loaded Co3O4 / AgIO4 composite photocatalyst and its preparation method and application

Abstract

The present invention discloses a carbon cloth-loaded Co3O4 / AgIO4 composite photocatalyst and a preparation method and application thereof, and relates to the field of photocatalytic technology. The present invention controls the morphology of Co3O4 in the composite photocatalyst so that Co3O4 and AgIO4 are closely compounded, thereby preventing AgIO4 from falling off due to photocorrosion and improving the stability of the composite catalyst. The composite photocatalyst carrier is carbon cloth, which is easy to recycle, and effectively solves the problem that powdered photocatalysts are difficult to recycle and easily cause secondary pollution. In addition, the Co3O4 and AgIO4 loaded on the carbon cloth can be compounded to form a heterojunction, thereby improving the photocatalytic activity.

Description

Technical Field

[0001] The present invention relates to the field of photocatalysis technology, and more specifically to a carbon cloth-loaded Co3O4 / AgIO4 composite photocatalyst and a preparation method and application thereof. Background Art

[0002] Photocatalytic technology based on semiconductor photocatalysts has the advantages of simple operation, mild reaction conditions, fast reaction rate, high efficiency, no secondary pollution, and low energy consumption. Its application in the purification of organic pollutants has attracted widespread attention. Currently, the most representative semiconductor photocatalyst materials are TiO2 and ZnO, but they have a large bandgap and can only respond to ultraviolet light, which greatly limits the absorption and utilization of sunlight.

[0003] In recent years, some Ag-based photocatalysts have shown excellent photocatalytic activity in degrading organic pollutants under visible light irradiation. The prior art discloses a visible light catalyst, the component of which is silver periodate (AgIO4), which has the advantages of a wide light response range and high utilization rate of visible light. However, the component of the catalyst is only silver periodate, which is easily decomposed by light corrosion, resulting in the shedding of silver periodate, poor catalyst stability, and the catalyst is a powder catalyst, which is difficult to recycle. Summary of the invention

[0004] In order to overcome the defects and shortcomings of the existing silver periodate catalyst, which has poor stability and leads to low catalytic activity, the present invention provides a carbon cloth-loaded Co3O4 / AgIO4 composite photocatalyst. By controlling the morphology of Co3O4, Co3O4 and AgIO4 are tightly combined to prevent AgIO4 from falling off, thereby improving the stability of the composite catalyst and further improving the photocatalytic activity of the composite catalyst. The carrier is carbon cloth, which is easy to recycle.

[0005] Another object of the present invention is to provide a method for preparing the above-mentioned carbon cloth-loaded Co3O4 / AgIO4 composite photocatalyst.

[0006] Another object of the present invention is to provide an application of the above-mentioned carbon cloth-loaded Co3O4 / AgIO4 composite photocatalyst in the field of photocatalytic technology.

[0007] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0008] A carbon cloth-supported Co3O4 / AgIO4 composite photocatalyst, wherein the composite catalyst carrier is carbon cloth and the active components are Co3O4 and AgIO4;

[0009] Wherein, the Co3O4 has a nanosheet structure.

[0010] It should be noted that:

[0011] The Co3O4 has a nanosheet structure and a large specific surface area, which can provide abundant active sites. Co3O4 and AgIO4 are combined together by chemical bonds. The abundant active sites can improve the binding density between the two, so that AgIO4 grows tightly on the Co3O4 nanosheets through chemical bonds, and achieves a tight compound with Co3O4, effectively preventing AgIO4 from falling off, thereby improving the stability of the combination between the AgIO4 catalyst and Co3O4, and further improving the photocatalytic activity.

[0012] Co3O4 and AgIO4 loaded on carbon cloth can also form a heterojunction. The built-in electric field of the heterojunction can effectively reduce the recombination efficiency of photogenerated electron-hole pairs and further improve the photocatalytic activity.

[0013] The carrier of the composite photocatalyst described in the present invention is a carbon cloth with good conductivity, large specific surface area, high strength, good thermal stability, good corrosion resistance and easy recycling. It effectively solves the problem that the existing powdered photocatalyst is difficult to recycle, does not cause secondary pollution, and can also improve the catalytic performance of the composite catalyst to a certain extent.

[0014] Specifically, the carbon cloth is carbon fiber cloth, which can be obtained through conventional purchase.

[0015] Specifically, the loading amount of Co3O4 is 20-35% of the total mass of the active components, for example, it can be 23.6%, 27.6%, 31.3%, 27.1%, 31.6%, and more specifically 23-32%.

[0016] When the Co3O4 loading is too low, it is not conducive to its complete growth on the carbon cloth fiber, reducing the active sites for AgIO4 deposition; when the Co3O4 loading is too high, the excessive density between the nanosheets will lead to increased stress, and the Co3O4 nanosheets grown on the carbon cloth are prone to breakage or even fall off the surface of the carbon cloth fiber, which is not conducive to improving the stability of the composite catalyst.

[0017] Preferably, the loading amount of Co3O4 is 30-32%, for example, 31.3%, 31.6%, and more preferably 31.3%.

[0018] Specifically, the loading amount of AgIO4 is 65-80% of the total mass of the active components, for example, it can be 68.4%, 68.7%, 72.4%, 72.9%, 76.4%, and more specifically 68-77%.

[0019] AgIO4 is the main active substance involved in the photocatalytic reaction. When the AgIO4 content is low, the photocatalytic activity of the obtained composite catalyst is also correspondingly low; when the AgIO4 content is high, the AgIO4 particles will form dense accumulation, resulting in a decrease in the specific surface area of ​​the composite catalyst, a decrease in active sites, and a decrease in photocatalytic performance.

[0020] Preferably, the loading amount of AgIO4 is 68-70%, for example, 68.4%, 68.7%, and more preferably 68.7%.

[0021] Specifically, the growth thickness of the Co3O4 nanosheets on the carbon cloth is 4 to 6 μm, for example, 4.67 μm, 4.45 μm, 4.56 μm, 5.25 μm, 5.88 μm, more specifically 4.45 to 5.88 μm.

[0022] The growth thickness of Co3O4 nanosheets on carbon cloth refers to the thickness of deposited multilayer nanosheets, not the thickness of single nanosheets. If the growth thickness of Co3O4 nanosheets is too thin, it is not conducive to the deposition of AgIO4 and the close combination with AgIO4, which will reduce the stability and photocatalytic activity of the composite catalyst to a certain extent; while if the thickness is too thick, it is not conducive to the stable growth of Co3O4 nanosheets on carbon cloth, which will also reduce the photocatalytic activity.

[0023] Preferably, the growth thickness of the Co3O4 nanosheets on the carbon cloth is 4.5-5.9 μm, specifically 4.6-5.88 μm, and more preferably 4.67 μm.

[0024] Specifically, the mass ratio of Co3O4 to AgIO4 is 1:(2-3.5), preferably 1:(2-3), more preferably 1:(2-2.5), and even more preferably 1:2.19.

[0025] By controlling the mass ratio of Co3O4 and AgIO4, the relative loading of the two can be better controlled, so that Co3O4 and AgIO4 can be more closely combined, while better promoting the formation of a heterojunction between the two and improving the photocatalytic activity of the composite catalyst.

[0026] The present invention specifically protects a method for preparing the above-mentioned carbon cloth-supported Co3O4 / AgIO4 composite photocatalyst, comprising the following steps:

[0027] S1. The carbon cloth is used as the working electrode and the cobalt salt aqueous solution is used as the electrolyte to assemble a three-electrode system for constant potential deposition. After deposition for 30 to 70 minutes, the system is taken out and dried;

[0028] S2. calcining the carbon cloth dried in step S1 at 350-450° C. to obtain a carbon cloth-loaded Co3O4 material;

[0029] S3. Soaking the carbon cloth loaded with Co3O4 material obtained in step S2 in a silver salt aqueous solution to allow the carbon cloth to fully absorb silver ions, then taking out the carbon cloth and soaking it in a periodate aqueous solution, and then putting it back into the silver salt aqueous solution after being fully soaked, alternately soaking to allow the silver salt and periodate to fully react, and post-processing to obtain a carbon cloth loaded with Co3O4 / AgIO4 composite photocatalyst;

[0030] Wherein, the immersion is carried out under light-proof conditions.

[0031] In step S1, the material is prepared by electrochemical deposition. The longer the deposition time, the more and denser the Co3O4 nanosheets will be, and the thickness of the nanosheets will increase accordingly. In addition, too short a deposition time will lead to insufficient cobalt salt loading, resulting in too low a Co3O4 loading on the final carbon cloth.

[0032] The calcination temperature in step S2 will affect the formation of Co3O4. Only when the temperature is controlled within the corresponding range can the carbon cloth-loaded Co3O4 material be successfully obtained.

[0033] In step S3, the carbon cloth is alternately immersed in a silver salt aqueous solution and a periodate aqueous solution, so that the silver salt and the periodate react fully and form AgIO4 on the carbon cloth loaded with Co3O4.

[0034] Specifically, the deposition voltage in step S1 is -1.1V to -0.9V.

[0035] Controlling the deposition voltage can further promote the deposition of cobalt salt on carbon cloth.

[0036] Specifically, in step S3, the first immersion time in the silver salt aqueous solution is 8 to 10 hours, and the second and subsequent immersion times are 0.5 to 1 minute.

[0037] Controlling the immersion time can allow the carbon cloth to fully absorb the silver salt. The first immersion time is longer to allow the carbon cloth to fully absorb the silver ions in the solution, so that more silver ions react with periodate to generate more silver periodate.

[0038] Specifically, in step S3, the immersion time in the periodate aqueous solution is 0.5 to 1 min.

[0039] Controlling the immersion time in periodate can ensure that the carbon cloth fully absorbs periodate and allows periodate and silver salt to fully react.

[0040] The carbon cloth of the present invention is a conventional commercially available carbon cloth, which is washed with acetone, anhydrous ethanol and deionized water for 15 to 25 minutes respectively, and then placed in a drying oven at 60° C. for drying, and then used to prepare a carbon cloth-loaded Co3O4 / AgIO4 composite photocatalyst.

[0041] The cobalt salt in step S1 can be cobalt nitrate. Cobalt nitrate hexahydrate is dissolved in deionized water and stirred for 30 to 60 minutes to obtain a cobalt salt aqueous solution. The mass percentage of cobalt nitrate hexahydrate to water is 1 to 2%.

[0042] In the three-electrode system of step S1, the material of the counter electrode is one of platinum sheet, platinum wire and platinum mesh, preferably platinum sheet; the reference electrode is Ag / AgCl electrode or calomel electrode, preferably Ag / AgCl electrode.

[0043] Specifically, in step S1, the carbon cloth is taken out after deposition, washed with deionized water and anhydrous ethanol for three times respectively, and then placed in a drying oven at 60° C. for 6 to 8 hours to remove impurities and dry the carbon cloth.

[0044] Specifically, the calcination time in step S2 is 1 to 3 hours.

[0045] The periodate in step S3 can be sodium periodate. Sodium periodate is dissolved in deionized water and stirred for 30 to 60 minutes in a light-proof condition to obtain a periodate aqueous solution.

[0046] Specifically, in step S3, the mixture is alternately immersed for 15 to 20 times.

[0047] The post-treatment in step S3 is: after removing the carbon cloth, wash with deionized water for 3 times, and dry in a drying oven at 60° C. for 6 to 8 hours.

[0048] The present invention particularly protects the application of the above-mentioned carbon cloth-loaded Co3O4 / AgIO4 composite photocatalyst in the field of photocatalytic technology.

[0049] The carbon cloth-supported Co3O4 / AgIO4 composite photocatalyst obtained by the present invention has high photocatalytic activity, and due to the composite of nano-sheet Co3O4 and AgIO4, the shedding of AgIO4 is prevented, and the photocatalytic stability is good. In addition, the carbon cloth-supported Co3O4 / AgIO4 composite photocatalyst uses carbon cloth as a carrier, is easy to recycle, and does not form secondary pollution.

[0050] Specifically, the carbon cloth-loaded Co3O4 / AgIO4 composite photocatalyst is used in photocatalytic degradation of organic pollutants.

[0051] Specifically, the organic pollutant is rhodamine B.

[0052] When the concentration of rhodamine B is 1.0×10 -5 mol / L, the photocatalytic degradation rate of Rhodamine B by the carbon cloth-loaded Co3O4 / AgIO4 composite photocatalyst of the present invention can reach 99%.

[0053] Compared with the prior art, the present invention has at least the following beneficial effects:

[0054] The present invention provides a carbon cloth-supported Co3O4 / AgIO4 composite photocatalyst. By controlling the morphology of Co3O4 in the composite photocatalyst, Co3O4 and AgIO4 are closely compounded to prevent AgIO4 from falling off due to photocorrosion, thereby improving the stability of the composite catalyst and further enhancing the photocatalytic activity. The composite photocatalyst carrier is carbon cloth, which is easy to recycle, and effectively solves the problem that powdered photocatalysts are difficult to recycle and easily cause secondary pollution. In addition, the Co3O4 and AgIO4 supported on the carbon cloth can be compounded to form a heterojunction, further improving the photocatalytic activity of the composite catalyst.

[0055] The carbon cloth-loaded Co3O4 / AgIO4 composite photocatalyst of the present invention is suitable for the field of photocatalysis. When photocatalytically degrading rhodamine B, the degradation rate reaches more than 90%. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 This is the SEM image of the carbon cloth loaded Co3O4 material of Example 6.

[0057] Figure 2 This is the SEM image of the carbon cloth loaded Co3O4 / AgIO4 composite photocatalyst of Example 1.

[0058] Figure 3 This is the TEM image of the carbon cloth loaded Co3O4 / AgIO4 composite photocatalyst of Example 1.

[0059] Figure 4 It is a comparison chart of the degradation rate of Rhodamine B by Example 1, Comparative Example 1, Comparative Example 2 and pure carbon cloth (CC).

[0060] Figure 5 This is a SEM image of the carbon cloth-loaded Co3O4 / AgIO4 composite photocatalyst after degrading Rhodamine B once in Example 1. DETAILED DESCRIPTION

[0061] The present invention is further described below in conjunction with specific embodiments, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0062] In the following embodiments and comparative examples of the present invention, the specific steps of cleaning the carbon cloth, preparing the cobalt nitrate aqueous solution, and preparing the sodium periodate aqueous solution are as follows:

[0063] Carbon cloth cleaning:

[0064] The carbon cloth was ultrasonically cleaned with 20 mL of acetone, 20 mL of anhydrous ethanol and 20 mL of deionized water for 20 min respectively to remove surface impurities, and then dried in a drying oven at 60° C. for 2 h; the mass of the carbon cloth was 0.0451 g.

[0065] Preparation of cobalt nitrate aqueous solution:

[0066] Dissolve 1.455 g of Co(NO3)2·6H2O in 100 mL of deionized water and stir for 30 min to obtain a cobalt nitrate aqueous solution.

[0067] Preparation of sodium periodate aqueous solution:

[0068] Weigh 0.2139 g of NaIO4 and dissolve it in 20 mL of deionized water. Stir for 30 min in the dark to obtain a sodium periodate aqueous solution.

[0069] Example 1

[0070] A carbon cloth-supported Co3O4 / AgIO4 composite photocatalyst, wherein the carrier of the composite catalyst is carbon cloth and the active components are Co3O4 and AgIO4;

[0071] Wherein, the Co3O4 has a nanosheet structure, and the growth thickness of the Co3O4 on the surface of the carbon cloth fiber is 4.67 μm;

[0072] The mass content of the active component Co3O4 is 31.3% (i.e., the loading amount) of the total mass of the composite catalyst;

[0073] The mass content of the active component AgIO4 is 68.7% (i.e., the loading amount) of the total mass of the composite catalyst;

[0074] The mass ratio of Co3O4 to AgIO4 is 1:2.19.

[0075] Embodiments 2 to 5

[0076] A carbon cloth-supported Co3O4 / AgIO4 composite photocatalyst, the structure and composition are the same as those in Example 1, and the differences are shown in Table 1.

[0077] Table 1. Parameters of carbon cloth-supported Co3O4 / AgIO4 composite photocatalyst

[0078]

[0079] Example 6

[0080] A method for preparing the carbon cloth-supported Co3O4 / AgIO4 composite photocatalyst described in Examples 1 to 5 comprises the following steps:

[0081] S1. Assemble the carbon cloth as the working electrode, the platinum sheet as the counter electrode, the Ag / AgCl as the reference electrode, and the cobalt nitrate aqueous solution as the electrolyte to form a three-electrode system for constant potential deposition. The deposition voltage is -1V and the deposition time is 30 to 70 minutes. After deposition, take out the carbon cloth, wash it with anhydrous ethanol and deionized water three times respectively, and dry it in a drying oven at 60°C for 6 hours;

[0082] S2. Place the carbon cloth dried in step S1 into a muffle furnace and calcine at 400° C. for 2 h to obtain a carbon cloth-loaded Co3O4 material;

[0083] S3. Soak the carbon cloth loaded with Co3O4 obtained in step S2 in a 0.05 mol / L silver nitrate solution for 10 h, take it out and soak it in a sodium periodate aqueous solution for 1 min, put it back into the silver nitrate solution and soak it for 1 min, alternately soak it 20 times, take it out and wash it with deionized water for 3 times, dry it in a drying oven at 60°C for 6 h, and obtain a carbon cloth loaded with Co3O4 / AgIO4 composite photocatalyst;

[0084] Wherein, the immersion is carried out under light-proof conditions.

[0085] In step S1 of carbon cloth loading Co3O4 / AgIO4 composite photocatalyst in Examples 2 to 5, the deposition time is shown in Table 2.

[0086] Table 2. Electrochemical deposition time of carbon cloth-supported Co3O4 / AgIO4 composite photocatalyst

[0087]

[0088] Comparative Example 1

[0089] A carbon cloth-loaded AgIO4 photocatalyst comprises a carbon cloth as a carrier and AgIO4 as an active component.

[0090] The preparation method of the above carbon cloth loaded AgIO4 photocatalyst is as follows:

[0091] S1. The carbon cloth was ultrasonically cleaned with 20 mL of acetone, 20 mL of anhydrous ethanol and 20 mL of deionized water for 20 min to remove surface impurities, and then dried in a drying oven at 60 °C for 2 h.

[0092] S2. Soak the dried carbon cloth in S1 in 0.05 mol / L silver nitrate solution in dark conditions for 10 h;

[0093] S3. Weigh 0.2139 g NaIO4 and dissolve it in 20 mL deionized water. Stir for 30 min in the dark.

[0094] S4. Under dark conditions, take out the carbon cloth soaked in the silver nitrate solution in S2, put it into the sodium periodate aqueous solution in S3, soak it for 1 minute, then take out the carbon cloth and put it back into the silver nitrate solution in S2; soak it alternately in the two solutions for 20 times, wash it with deionized water 3 times after taking it out, and dry it in a drying oven at 60°C for 6 hours to obtain the carbon cloth-loaded AgIO4 photocatalytic material.

[0095] Comparative Example 2

[0096] A carbon cloth-supported Co3O4 photocatalyst, wherein the Co3O4 has a 4.67 μm-thick nanosheet structure.

[0097] The preparation method of the above carbon cloth-loaded Co3O4 photocatalyst is as follows:

[0098] S1. The carbon cloth was ultrasonically cleaned with 20 mL of acetone, 20 mL of anhydrous ethanol and 20 mL of deionized water for 20 min to remove surface impurities, and then dried in a drying oven at 60 °C for 2 h.

[0099] S2. Dissolve 1.455 g Co(NO3)2·6H2O in 100 mL deionized water and stir for 30 min;

[0100] S3. Assemble a three-electrode system using an electrochemical workstation, with the treated carbon cloth in S1 as the working electrode, the platinum sheet as the counter electrode, Ag / AgCl as the reference electrode, and the Co(NO3)2·6H2O solution prepared in S2 as the electrolyte. Select the constant potential deposition method, with a deposition voltage of -1V and a deposition time of 3000s. After deposition, take out the carbon cloth, wash it three times with anhydrous ethanol and deionized water respectively, and dry it in a drying oven at 60°C for 6h.

[0101] S4. Place the carbon cloth after electrodeposition in S3 into a muffle furnace and heat it at 400°C for 2 hours to obtain carbon cloth loaded with CO3O4.

[0102] Results

[0103] Photocatalytic activity test:

[0104] Using a xenon lamp with a fixed wavelength of 420nm as the visible light source, the target organic pollutant RhB (Rhodamine B) was degraded at room temperature to evaluate the photocatalytic activity of the carbon cloth-supported Co3O4 / AgIO4 composite photocatalyst.

[0105] Take one piece (2cm×2cm) of the carbon cloth-loaded Co3O4 / AgIO4 composite photocatalyst of the above embodiment and comparative example, and place it vertically in a beaker containing 60mL of RhB solution. Before turning on the xenon lamp for illumination, place the reaction system in the dark for magnetic stirring for 30min to achieve adsorption equilibrium between the catalyst and RhB. During the illumination process, take 4mL of supernatant with a disposable dropper every 5min, inject it into a cuvette, and measure the absorbance of the solution with a UV-visible spectrophotometer. The activity of the photocatalyst is evaluated by comparing the reaction rate constant (k=-ln(C / C0) / t). The degradation rate of RhB is the degradation rate of the reaction for 40min, which can be calculated by (C0-C) / C0.

[0106] In the formula, C0 and C are the initial concentration of RhB solution and the concentration when the illumination time is t, respectively, k is the reaction rate constant, and t is the illumination time. The larger the k, the faster the reaction rate and the higher the photocatalytic activity.

[0107] The results are shown in Table 3.

[0108] Table 3. Performance test results of catalysts of Examples and Comparative Examples

[0109]

[0110]

[0111] It can be seen from Table 3 that the carbon cloth-supported Co3O4 / AgIO4 composite photocatalyst of the present invention has a high reaction rate and degradation rate, and its reaction rate constant is not less than 0.0511min -1 , the degradation rate is not less than 90.04%; in Comparative Examples 1 and 2, only AgIO4 or Co3O4 is loaded, and its reaction rate constant is significantly smaller than that of the embodiment of the present invention, and the degradation rate is also lower.

[0112] Figure 1 This is the SEM image of the carbon cloth loaded Co3O4 material of Example 6. The nano-sheet Co3O4 completely covers the carbon cloth with a thickness of 4.67 μm. The Co3O4 nanosheets are interlaced and connected to each other, forming more gaps, increasing the specific surface area, and improving the adsorption performance of the carbon cloth loaded Co3O4 / AgIO4 composite photocatalyst. At the same time, the nano-sheet Co3O4 provides abundant loading active sites for the deposition of AgIO4, which is more conducive to the deposition of AgIO4.

[0113] Figure 2This is the SEM image of the carbon cloth-loaded Co3O4 / AgIO4 composite photocatalyst of Example 1. A large number of AgIO4 polyhedral particles are deposited on the surface of the Co3O4 nanosheets. The diameter of the AgIO4 particles is 1 to 3 μm, and the Co3O4 is completely wrapped.

[0114] Figure 3 This is the TEM image of the carbon cloth-loaded Co3O4 / AgIO4 composite photocatalyst of Example 1, which is mainly composed of relatively transparent Co3O4 nanosheets and darker irregular AgIO4 particles, wherein the diameter of the Co3O4 nanosheets is about 0.5-1 μm, and the diameter of AgIO4 is 2-2.2 μm, which further clarifies the diameter of AgIO4 compared to the SEM image.

[0115] Figure 4 The following is a comparison of the degradation rates of Rhodamine B (RhB) by Example 1, Comparative Example 1, Comparative Example 2 and carbon cloth. It can be seen from the figure that the RhB solution without any photocatalyst is almost unaffected by visible light irradiation, and pure carbon cloth has almost no adsorption and degradation effect on RhB molecules. This is because the surface of the carbon cloth fiber is relatively smooth and the carbon cloth is not a photocatalyst. Carbon cloth loaded with Co3O4 (CC@Co3O4) exhibits certain adsorption performance, which is caused by a large number of Co3O4 nanosheets deposited on the surface of the carbon cloth. Carbon cloth loaded with AgIO4 (CC@AgIO4) exhibits good photocatalytic performance, and carbon cloth loaded with Co3O4 / AgIO4 composite photocatalyst (CC@Co3O4 / AgIO4) exhibits good adsorption performance and photocatalytic degradation performance. The adsorption capacity of CC@Co3O4 / AgIO4 sample was 27.84%, which was 2.78 times and 1.92 times of the adsorption capacity of CC@Co3O4 (10.01%) and CC@AgIO4 (14.5%), respectively. After 40 minutes of illumination, CC@Co3O4 / AgIO4 degraded 99.2% of the RhB solution, while CC@AgIO4 only degraded 83.41% of the RhB solution, and CC@Co3O4 only degraded 16.31% of the RhB solution. The results show that the addition of Co3O4 can play a synergistic role with AgIO4, improving the adsorption performance and photocatalytic activity of the catalyst.

[0116] Figure 5This is a SEM image of the carbon cloth-loaded Co3O4 / AgIO4 composite photocatalyst of Example 1 after degrading Rhodamine B once. As can be seen from the figure, after the carbon cloth-loaded Co3O4 / AgIO4 composite photocatalyst degrades Rhodamine B once, only a small part of the silver periodate loaded on the surface of the carbon cloth falls off (as shown in the red frame in the figure), indicating that the carbon cloth-loaded Co3O4 / AgIO4 composite photocatalyst of the present invention can control the morphology of Co3O4, so that Co3O4 and AgIO4 are closely combined, prevent AgIO4 from falling off, improve the stability of the composite catalyst, and then enhance the photocatalytic activity of the composite catalyst.

[0117] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A carbon cloth-supported Co3O4 / AgIO4 composite photocatalyst, characterized in that: The carrier of the composite photocatalyst is carbon cloth, and the active components are Co3O4 and AgIO4; the Co3O4 has a nanosheet structure; the carbon cloth-loaded Co3O4 / AgIO4 composite photocatalyst is prepared by the following method: S1. The carbon cloth is used as the working electrode and the cobalt salt aqueous solution is used as the electrolyte to assemble a three-electrode system for constant potential deposition. After deposition for 30 to 70 minutes, the system is taken out and dried; S2. calcining the carbon cloth dried in step S1 at 350-450° C. to obtain a carbon cloth-loaded Co3O4 material; S3. Soaking the carbon cloth loaded with Co3O4 material obtained in step S2 in a silver salt aqueous solution to allow the carbon cloth to fully absorb silver ions, then taking out the carbon cloth and soaking it in a periodate aqueous solution, and then putting it back into the silver salt aqueous solution after being fully soaked, alternately soaking to allow the silver salt and periodate to fully react, and post-processing to obtain a carbon cloth loaded with Co3O4 / AgIO4 composite photocatalyst; Wherein, the immersion is carried out under light-proof conditions; The loading amount of Co3O4 is 20-35% of the total mass of the active components; The loading amount of AgIO4 is 65-80% of the total mass of the active components; The growth thickness of the Co3O4 nanosheets on the carbon cloth is 4-6 μm.

2. The carbon cloth-supported Co3O4 / AgIO4 composite photocatalyst as claimed in claim 1, characterized in that: The loading amount of Co3O4 is 30-32% of the total mass of the active components.

3. The carbon cloth-supported Co3O4 / AgIO4 composite photocatalyst according to claim 1, characterized in that: The loading amount of AgIO4 is 68-70% of the total mass of the active components.

4. The carbon cloth-supported Co3O4 / AgIO4 composite photocatalyst as claimed in claim 1, characterized in that: The growth thickness of the Co3O4 nanosheets on the carbon cloth is 4.5-5.9 μm.

5. A method for preparing the carbon cloth-supported Co3O4 / AgIO4 composite photocatalyst according to any one of claims 1 to 4, characterized in that: The steps include: S1. The carbon cloth is used as the working electrode and the cobalt salt aqueous solution is used as the electrolyte to assemble a three-electrode system for constant potential deposition. After deposition for 30 to 70 minutes, the system is taken out and dried; S2. calcining the carbon cloth dried in step S1 at 350-450° C. to obtain a carbon cloth-loaded Co3O4 material; S3. Soaking the carbon cloth loaded with Co3O4 material obtained in step S2 in a silver salt aqueous solution to allow the carbon cloth to fully absorb silver ions, then taking out the carbon cloth and soaking it in a periodate aqueous solution, and then putting it back into the silver salt aqueous solution after being fully soaked, alternately soaking to allow the silver salt and periodate to fully react, and post-processing to obtain a carbon cloth loaded with Co3O4 / AgIO4 composite photocatalyst; Wherein, the immersion is carried out under light-proof conditions.

6. The preparation method according to claim 5, characterized in that: The deposition voltage in step S1 is -1.1V to -0.9V.

7. Use of the carbon cloth-supported Co3O4 / AgIO4 composite photocatalyst as claimed in any one of claims 1 to 4 in the field of photocatalytic technology.

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