A method for preparing visible light catalyst by electrochemical deposition

Abstract

The present invention relates to the field of catalyst preparation, and in particular to a method for preparing a visible light catalyst by using an electrochemical deposition method, comprising obtaining a temperature reference value and a temperature fluctuation value of organic wastewater in a target scene; determining a detection temperature range and a heating rate in catalytic detection according to acquisition characteristics of the target scene; performing catalytic detection on a target catalyst to obtain catalytic parameters of the target catalyst, and determining to analyze a reference SEM image when the catalytic parameters are in a preset catalytic parameter state; determining an image parameter state of a reference SEM image according to an image reference value and a growth fluctuation value, and determining a specific adjustment method of a compensation parameter according to the image parameter state of the reference SEM image; the present invention improves the preparation effect of the visible light catalyst.

Description

Technical Field

[0001] The present invention relates to the field of catalyst preparation, and in particular to a method for preparing a visible light catalyst by using an electrochemical deposition method. Background Art

[0002] With the increase of environmental pollution problems caused by industrial development, more and more serious water pollution will seriously threaten people's health. The use of photocatalysts to degrade toxic substances in water has become a new work in the field of environmental protection. ZnO, as a wide-bandgap semiconductor photocatalytic material, has a narrow light response range, mainly concentrated in the ultraviolet light region. However, through the composite with rGO (reduced graphene oxide), the photocatalytic performance of ZnO has been significantly improved. Studies have shown that ZnO-rGO composite materials show good performance in the photodegradation of methylene blue solution under ultraviolet light. However, in actual applications, since the wastewater temperature at the discharge end is not constant, the temperature of the organic wastewater at the discharge end will affect the stability of the catalyst during use and the catalytic efficiency. Therefore, the catalytic efficiency of the ZnO-rGO composite material prepared by the conventional preparation process is poor.

[0003] Chinese patent publication number CN107285370A discloses a one-step synthesis preparation method of a flaky rGO / ZnO nanocomposite material, the method specifically includes: using graphene oxide GO, zinc acetate dihydrate as raw materials, ethanolamine (MEA) as a surfactant, and undergoing solvent thermal method and calcination treatment, and one-step growth synthesis to obtain irregular flaky ZnO on the rGO carrier, i.e., rGO / ZnO composite material. It can be seen that the method has the following problems: the influence of the temperature of the wastewater to be treated on the effect of the catalyst in the actual use environment is not taken into account, which leads to poor applicability of the prepared material, and the solvent thermal reaction process is relatively complicated, and it is difficult to accurately control the reaction conditions, so that it is impossible to effectively adjust the reaction parameters according to the catalytic effect of the catalyst actually prepared, which further leads to poor catalytic efficiency. Summary of the invention

[0004] To this end, the present invention provides a method for preparing a visible light catalyst using an electrochemical deposition method, so as to overcome the problem that the solvent thermal reaction process in the prior art is relatively complicated and does not take into account the influence of the temperature of the wastewater to be treated in the actual use environment on the use effect of the catalyst, thereby resulting in poor applicability of the prepared material.

[0005] To achieve the above object, the present invention provides a method for preparing a visible light catalyst by electrochemical deposition, comprising:

[0006] Obtain the temperature reference value and temperature fluctuation value of the organic wastewater in the target scene;

[0007] Determine the detection temperature range and heating rate in catalytic detection based on the target scene acquisition characteristics;

[0008] Performing catalytic testing on the target catalyst to obtain catalytic parameters of the target catalyst, and determining to analyze the reference SEM image when the catalytic parameters are in a preset catalytic parameter state;

[0009] The image parameter state of the reference SEM image is determined according to the image reference value and the growth fluctuation value, and the specific adjustment method of the compensation parameter is determined according to the image parameter state of the reference SEM image.

[0010] Further, the detection temperature range and the heating rate in the catalytic detection are determined according to the target scene acquisition characteristics;

[0011] The range threshold of the detection temperature range is determined according to the temperature reference value;

[0012] The heating rate is determined according to the temperature fluctuation value;

[0013] The target scene acquisition feature is determined based on the temperature reference value and temperature fluctuation value of the organic wastewater.

[0014] Further, the target scene acquisition feature includes that the temperature reference value is within a first preset temperature reference value range, or that the temperature reference value is within a second preset temperature reference value range and the temperature fluctuation value is within the second preset temperature reference value range;

[0015] The detection temperature range is related to the temperature reference value;

[0016] The preset heating rate is related to the temperature fluctuation value.

[0017] Further, a catalytic test is performed on the target catalyst to obtain the catalytic parameters of the target catalyst, and when the catalytic parameters are in a preset catalytic parameter state, it is determined to analyze the reference SEM image;

[0018] The catalytic parameters include a catalytic efficiency fluctuation value and a catalytic efficiency reference value.

[0019] Further, the analysis of the reference SEM image includes the following steps:

[0020] Perform image cutting on the reference SEM image to obtain several initial sub-region images;

[0021] Performing a preset number of image expansions on each initial sub-region image, and obtaining a characteristic image growth value corresponding to each image expansion;

[0022] The image parameter state is determined according to the image reference value of the reference SEM image and the growth fluctuation value.

[0023] Furthermore, each initial sub-region image is a circular region established with the initial point as the center and a preset initial radius. The number of initial sub-region images is recorded as n. For the i-th initial sub-region image, the image after the r-th image expansion is recorded as the ir-th expanded image. The absolute value Hi r of the difference in the number of feature images between each ir-th expanded image and the ir+1-th expanded image is calculated, and the average value of Hi r is recorded as the feature image growth value.

[0024] Further, the growth fluctuation value of the reference SEM image is determined according to the characteristic image growth value of each initial sub-region image;

[0025] The image reference value of the reference SEM image is determined according to the number of characteristic images of each initial sub-region image.

[0026] Further, the duration of the ultraviolet ozone treatment is adjusted according to the image parameter state of the reference SEM image, or the concentration of the precursor solution is adjusted;

[0027] The compensation parameters include the UV-ozone treatment time and the precursor solution concentration.

[0028] Further, the image parameter state includes that the image reference value is within a second reference value range, or that the image reference value is within a first reference value range and the growth fluctuation value is within a second growth fluctuation value range.

[0029] Furthermore, the precursor solution is an electrolyte solution including a ZnO precursor and an rGO precursor.

[0030] Compared with the prior art, the beneficial effect of the present invention lies in that, in the technical scheme of the present invention, the target scene acquisition characteristics are determined according to the temperature reference value and the temperature fluctuation value of the organic wastewater, and then the detection temperature range and the heating rate in the catalytic detection are determined, so that the effect of the catalytic detection is more in line with the actual application scenario, avoiding the problem of poor catalyst detection effect caused by the detection temperature not conforming to the actual usage due to conventional unified detection. In addition, the present invention adopts an electrochemical deposition method to prepare the catalyst. Compared with other existing preparation methods, the control and adjustment of the preparation parameters of the electrochemical deposition method is easier, thereby improving the preparation effect. In addition, in the present invention, the image parameter state of the reference SEM image is determined according to the image reference value and the growth fluctuation value, and the specific adjustment method of the compensation parameter is determined according to the image parameter state of the reference SEM image, so that the specific adjustment method is more in line with the actual working scenario, and the adjustment efficiency of the specific adjustment method is provided, thereby improving the catalyst preparation efficiency.

[0031] In the present invention, the image parameter state of the reference SEM image is determined by the image reference value and the growth fluctuation value, and the image parameter state more accurately reflects the preparation uniformity and preparation amount of the catalyst, thereby improving the accuracy of the selection of the specific adjustment method. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the method for preparing a visible light photocatalyst by electrochemical deposition according to the present invention. DETAILED DESCRIPTION

[0033] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0034] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0035] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0036] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] See also Figure 1 As shown, the present invention provides a method for preparing a visible light catalyst by electrochemical deposition, comprising:

[0038] Obtain the temperature reference value and temperature fluctuation value of the organic wastewater in the target scene;

[0039] Determine the detection temperature range and heating rate in catalytic detection based on the target scene acquisition characteristics;

[0040] Performing catalytic testing on the target catalyst to obtain catalytic parameters of the target catalyst, and determining to analyze the reference SEM image when the catalytic parameters are in a preset catalytic parameter state;

[0041] The image parameter state of the reference SEM image is determined according to the image reference value and the growth fluctuation value, and the specific adjustment method of the compensation parameter is determined according to the image parameter state of the reference SEM image.

[0042] The present invention provides a method for preparing a visible light catalyst by electrochemical deposition, which is applied to the field of visible light catalyst preparation. The prepared visible light catalyst is a ZnO-rGO material, wherein a three-electrode system is specifically used to deposit the ZnO-rGO material, the working electrode is FTO conductive glass, the counter electrode is a spiral platinum wire, the reference electrode is an Ag / AgCl electrode, the precursor solution is an aqueous solution of 10mM Zn(NO3)2, 0.1M Li r lO4 and 5mg / L GO solution, the electrolytic cell as a reaction container is placed in a temperature-controlled water bath, and deposition is performed by a constant potential deposition method, and the deposition potential and deposition time are set by the user according to his own experience. After the deposition is completed, the FTO conductive glass with the ZnO-rGO material is taken out, rinsed with deionized water, blown dry, and placed in a muffle furnace, and annealed at 350°C for 30min in an air atmosphere to remove the residual moisture in the sample film.

[0043] Specifically, the detection temperature range and heating rate in catalytic detection are determined based on the target scene acquisition characteristics;

[0044] The range threshold of the detection temperature range is determined according to the temperature reference value;

[0045] The heating rate is determined according to the temperature fluctuation value;

[0046] The target scene acquisition feature is determined based on the temperature reference value and temperature fluctuation value of the organic wastewater.

[0047] Periodic detection is performed on organic wastewater at the wastewater discharge end in the target scenario. Several wastewater temperature detections are performed in each monitoring cycle. The value obtained from the cth temperature detection is recorded as Tc. The temperature reference value is the average value of the sum of all Tc's, which is 1. The temperature fluctuation value is the Tc with the largest value minus the Tc with the smallest value. If the temperature reference value is in the first preset temperature reference value range, the detection temperature of the catalytic detection is a fixed temperature, and the value of the fixed temperature is the temperature reference value. If the temperature reference value is in the second preset temperature reference value range and the temperature fluctuation value is in the second preset temperature reference value range, the detection temperature range in the catalytic detection is [Tcmin, Tcmax], in °C, the heating rate is V, Tcmin is the Tc with the smallest value, Tcmax is the Tc with the largest value, c is an integer greater than 0, c=1, 2, 3, ..., c0, c0 is the total number of wastewater temperature detections performed in a single monitoring cycle.

[0048] Specifically, the target scene acquisition feature includes that the temperature reference value is within a first preset temperature reference value range, or that the temperature reference value is within a second preset temperature reference value range and the temperature fluctuation value is within the second preset temperature reference value range;

[0049] The detection temperature range is related to the temperature reference value;

[0050] The preset heating rate is related to the temperature fluctuation value.

[0051] The values ​​within the first preset temperature reference value range are all less than the preset fluctuation value, and the values ​​within the second preset temperature reference value range are all greater than or equal to the preset fluctuation value. The user can set it according to the actual application scenario. The greater the user's demand for the catalytic efficiency of the catalyst, the smaller the preset fluctuation value. A preset fluctuation value is provided, and the preset fluctuation value is 20% of Tcmax. The heating rate is positively correlated with the preset fluctuation value.

[0052] Specifically, a catalytic test is performed on the target catalyst to obtain the catalytic parameters of the target catalyst, and when the catalytic parameters are in a preset catalytic parameter state, it is determined to analyze the reference SEM image;

[0053] The catalytic parameters include a catalytic efficiency fluctuation value and a catalytic efficiency reference value.

[0054] The catalytic test includes photocatalytic degradation of methylene blue (MB) as the target degradable organic matter using ZnO-rGO under the irradiation of a mercury lamp, and obtaining the change image of the ultraviolet-visible absorption spectrum of the degraded MB solution with the irradiation time, and using the Lambert-Beer law to calculate the concentration change of MB. The Lambert-Beer law shows that the absorbance (A) of the solution is proportional to its concentration (c), that is, A=εc l, where ε is the molar absorption coefficient, c is the concentration, and l is the optical path length. ε and l are recorded as preset constants, which are set by the user based on historical experience. By comparing the absorbance values ​​at different time points, the concentration change of MB can be calculated, and the percentage of MB concentration reduction when the catalytic time is 120 minutes is recorded as the catalytic efficiency reference value. After the initial catalytic test is completed, the ZnO-rGO is separated from the reaction solution for cleaning to remove the attached reactants and by-products, and the recovered ZnO-rGO is re-added to the new MB solution. The catalytic test is repeated several times and the catalytic efficiency reference value of the current catalytic test is recorded with the most recent last test when the catalytic test is completed. The absolute value of the difference between the catalytic efficiency reference values ​​is calculated, and the average value of the sum of the absolute values ​​is calculated and recorded as the catalytic efficiency fluctuation value. The preset catalytic parameter state is that the catalytic efficiency fluctuation value is greater than the preset catalytic efficiency fluctuation value or the catalytic efficiency reference value is less than the preset catalytic efficiency reference value. The preset catalytic efficiency fluctuation value and the preset catalytic efficiency reference value can be set by the user according to the actual application scenario. The higher the user's demand for the catalytic effect of the catalyst, the smaller the preset catalytic efficiency fluctuation value and the larger the value of the preset catalytic efficiency reference value. A preset catalytic efficiency fluctuation value and a preset catalytic efficiency reference value are provided. The preset catalytic efficiency fluctuation value is 3%, and the preset catalytic efficiency reference value is 95%.

[0055] Specifically, the analysis of the reference SEM image includes the following steps:

[0056] Perform image cutting on the reference SEM image to obtain several initial sub-region images;

[0057] Performing a preset number of image expansions on each initial sub-region image, and obtaining a characteristic image growth value corresponding to each image expansion;

[0058] The image parameter state is determined according to the image reference value of the reference SEM image and the growth fluctuation value.

[0059] The reference SEM image in the present invention is a product image on the FTO conductive glass when the ZnO-rGO material is prepared. The reference SEM image is an image generated by a scanning electron microscope. The image is formed by scanning the sample surface with a focused high-energy electron beam and collecting various signals generated by the interaction between the sample and the electron beam. This is a detection method well known to those skilled in the art and will not be described in detail here.

[0060] Specifically, each initial sub-region image is a circular region with the initial point as the center and a preset initial radius. The number of initial sub-region images is denoted as n. For the i-th initial sub-region image, the image after the r-th image expansion is denoted as the ir-th expanded image. The absolute value Hi r of the difference in the number of feature images between each ir-th expanded image and the ir+1-th expanded image is calculated, and the average value of Hi r is denoted as the feature image growth value.

[0061] The preset initial radius is set by the user according to the size of the reference SEM image. It is worth noting that the preset initial radius × the number of initial points < the length of any side of the reference SEM image. Each time the image is expanded, the radius of the initial sub-area is increased and adjusted to ensure that there is no overlapping area between any two expanded images after the increase. Each initial sub-area image corresponds to a characteristic image growth value.

[0062] Among them, the distance between each initial point and the adjacent initial point is the same. The number of initial points can be set by the user based on the number of pixel blocks in the SEM image and user needs. A value of the number of initial points is provided, and the number of initial points is 5. The setting height of each initial point in the reference SEM image is different.

[0063] The reference SEM image is binarized so that all pixels in the image have pixel values ​​of 0 or 255, and the points with non-0 pixel values ​​are recorded as feature points. The feature image number is the number of feature points in the corresponding image.

[0064] Specifically, the growth fluctuation value of the reference SEM image is determined according to the characteristic image growth value of each initial sub-region image;

[0065] The image reference value of the reference SEM image is determined according to the number of characteristic images of each initial sub-region image, and the number of characteristic images in the reference SEM image is recorded as the image reference value of the reference SEM image.

[0066] The method for confirming the growth fluctuation value of the reference SEM image is to extract the characteristic image growth value corresponding to each initial sub-region image, and subtract the characteristic image growth value with the largest value from the characteristic image growth value with the smallest value as the growth fluctuation value.

[0067] Specifically, the duration of the ultraviolet ozone treatment is adjusted according to the image parameter state of the reference SEM image, or the concentration of the precursor solution is adjusted;

[0068] The compensation parameters include the UV-ozone treatment time and the precursor solution concentration.

[0069] Specifically, the image parameter state includes that the image reference value is within the second reference value range, or that the image reference value is within the first reference value range and the growth fluctuation value is within the second growth fluctuation value range.

[0070] If the image reference value is within the second reference value range, increasing the duration of the ultraviolet ozone treatment is adjusted;

[0071] If the image reference value is within the first reference value range and the growth fluctuation value is within the second growth fluctuation value range, increasing the concentration of the precursor solution;

[0072] The ultraviolet ozone treatment duration is the duration of ultraviolet ozone treatment for FTO glass, and the increase adjustment amount of the ultraviolet ozone treatment duration is negatively correlated with the image reference value; the increase adjustment value of the precursor liquid concentration is positively correlated with the growth fluctuation value; a first reference value range, a second reference value range, a first growth fluctuation value range and a second growth fluctuation value range are set, wherein the values ​​within the first reference value range are all greater than the preset image reference value, the values ​​within the second reference value range are all less than or equal to the preset image reference value, the values ​​within the first growth fluctuation value range are all less than the preset growth fluctuation value, the values ​​within the second growth fluctuation value range are all greater than or equal to the preset growth fluctuation value, the preset image reference value and the values ​​within the preset growth fluctuation value can be set by the user according to the actual application scenario, the higher the user's demand for the catalytic efficiency of the catalyst, the larger the value of the preset image reference value, and the smaller the value of the preset growth fluctuation value.

[0073] Specifically, the precursor solution is an electrolyte solution including a ZnO precursor and a rGO precursor.

[0074] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

[0075] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a visible light photocatalyst by electrochemical deposition, characterized in that: include: Obtain the temperature reference value and temperature fluctuation value of the organic wastewater in the target scene; Determine the detection temperature range and heating rate in catalytic detection based on the target scene acquisition characteristics; Performing catalytic testing on the target catalyst to obtain catalytic parameters of the target catalyst, and determining to analyze the reference SEM image when the catalytic parameters are in a preset catalytic parameter state; Determine the image parameter state of the reference SEM image according to the image reference value and the growth fluctuation value, and determine the specific adjustment method of the compensation parameter according to the image parameter state of the reference SEM image; Determine the detection temperature range and heating rate in catalytic detection based on the target scene acquisition characteristics; The range threshold of the detection temperature range is determined according to the temperature reference value; The heating rate is determined according to the temperature fluctuation value; The target scene acquisition feature is determined based on the temperature reference value and temperature fluctuation value of the organic wastewater; The target scene acquisition feature includes that the temperature reference value is within a first preset temperature reference value range, or that the temperature reference value is within a second preset temperature reference value range and the temperature fluctuation value is within the second preset temperature reference value range; The detection temperature range is related to the temperature reference value; The preset heating rate is related to the temperature fluctuation value; Periodic detection is performed on the organic wastewater at the wastewater discharge end in the target scenario. The temperature of the wastewater is detected several times in each monitoring cycle. The value obtained by the cth temperature detection is recorded as Tc. The temperature reference value is the average value of the sum of all Tc values ​​1. The temperature fluctuation value is the Tc with the largest value-the Tc with the smallest value. If the temperature reference value is in the first preset temperature reference value range, the detection temperature of the catalytic detection is a fixed temperature, and the value of the fixed temperature is the temperature reference value. If the temperature reference value is in the second preset temperature reference value range and the temperature fluctuation value is in the second preset temperature reference value range, the detection temperature range in the catalytic detection is [Tcmin, Tcmax], the unit is ℃, the heating rate is V, Tcmin is the Tc with the smallest value, Tcmax is the Tc with the largest value, c is an integer greater than 0, c=1, 2, 3, ..., c0, c0 is the total number of wastewater temperature detections performed in a single monitoring cycle; The image parameter state includes that the image reference value is within the second reference value range, or that the image reference value is within the first reference value range and the growth fluctuation value is within the second growth fluctuation value range; Each initial sub-region image is a circular region with the initial point as the center and a preset initial radius. The number of initial sub-region images is recorded as n. For the i-th initial sub-region image, the image after the r-th image expansion is recorded as the ir-th expanded image. The absolute value Hir of the difference in the number of characteristic images between each ir-th expanded image and the ir+1-th expanded image is calculated, and the average value of Hir is recorded as the characteristic image growth value. The growth fluctuation value of the reference SEM image is determined according to the characteristic image growth value of each initial sub-region image; The image reference value of the reference SEM image is determined according to the number of characteristic images of each initial sub-region image; The reference SEM image is binarized so that all pixels in the image have pixel values ​​of 0 or 255, and the points with non-0 pixel values ​​are recorded as feature points, and the number of feature images is the number of feature points in the corresponding image; The method for confirming the growth fluctuation value of the reference SEM image is to extract the characteristic image growth value corresponding to each initial sub-region image, and subtract the characteristic image growth value with the largest value from the characteristic image growth value with the smallest value as the growth fluctuation value.

2. The method for preparing a visible light photocatalyst by electrochemical deposition according to claim 1, characterized in that: Performing catalytic testing on the target catalyst to obtain catalytic parameters of the target catalyst, and determining to analyze the reference SEM image when the catalytic parameters are in a preset catalytic parameter state; The catalytic parameters include a catalytic efficiency fluctuation value and a catalytic efficiency reference value.

3. The method for preparing a visible light photocatalyst by electrochemical deposition according to claim 2, characterized in that: The analysis of the reference SEM image includes the following steps: Perform image cutting on the reference SEM image to obtain several initial sub-region images; Performing a preset number of image expansions on each initial sub-region image, and obtaining a characteristic image growth value corresponding to each image expansion; The image parameter state is determined according to the image reference value of the reference SEM image and the growth fluctuation value.

4. The method for preparing a visible light photocatalyst by electrochemical deposition according to claim 3, characterized in that: Determine to adjust the duration of the ultraviolet ozone treatment according to the image parameter state of the reference SEM image, or adjust the concentration of the precursor solution; The compensation parameters include the UV-ozone treatment time and the precursor solution concentration.

5. The method for preparing a visible light photocatalyst by electrochemical deposition according to claim 4, characterized in that: The precursor solution is an electrolyte solution including a ZnO precursor and a rGO precursor.

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