Preparation method of catalytic anode based on porous tetragonal system lead dioxide coating
A porous tetragonal lead dioxide coating was prepared by linear scanning electrodeposition, which solved the problem of poor catalytic performance of lead dioxide-coated catalytic anode in OER, achieved efficient charge transfer and improved stability, and reduced energy consumption and production costs.
Patent Information
- Application Number
- CN202511283418.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-09
- Publication Date
- 2025-10-17
AI Technical Summary
Existing lead dioxide-coated catalytic anodes have poor catalytic performance in the oxygen evolution reaction (OER), a high OER overpotential that increases energy consumption, and insufficient stability in highly acidic and corrosive ion environments, affecting the efficiency and cost of the non-ferrous metal electrowinning process.
A porous tetragonal lead dioxide coating was prepared by linear scanning electrodeposition. By controlling the voltage window and scanning rate, a uniform three-dimensional porous structure was constructed, which improved the charge transfer efficiency and catalytic activity and reduced the OER overpotential.
Significantly reduce the OER overpotential, improve catalytic activity and corrosion resistance, extend the service life of the anode, and reduce the energy consumption of the electrolysis process.
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Abstract
Description
TECHNICAL FIELD
[0001] The application relates to a preparation method of a porous tetragonal lead dioxide coating catalytic anode, and belongs to the technical field of hydrometallurgy. BACKGROUND
[0002] Electrowinning process is one of the most important links in hydrometallurgy and is widely used in the extraction of non-ferrous metals such as zinc, nickel, manganese and lead. However, the high energy consumption caused by the poor oxygen evolution reaction (OER) catalytic performance of the lead-silver anode used in the electrowinning process has always been a topic of concern for researchers. In particular, the complex 4-electron transfer step and the generation of complex intermediates in OER lead to slow kinetics and high OER overpotential, resulting in increased ineffective energy consumption. In addition, in the electrowinning process, the special electrolyte environment with ultra-high acidity and various corrosive ions requires the anode material to have high corrosion resistance. Therefore, it is still a challenge to select an anode with high OER activity and stability suitable for electrowinning.
[0003] Lead dioxide (PbO2) coating electrode material has become a research hotspot in the fields of organic oxidation, lead-acid battery energy storage, non-ferrous metal extraction, environmental restoration and the like due to its unique advantages of high electrical conductivity, low cost, easy preparation and the like. PbO2 is divided into orthorhombic lead dioxide (alpha-PbO2) and tetragonal lead dioxide (beta-PbO2), wherein alpha-PbO2 has strong mechanical properties, thermal stability and bonding force and is often used as an intermediate layer, and beta-PbO2 has a large micro surface area, electrical conductivity and corrosion resistance and is the best choice for a surface active layer. Although beta-PbO2 has certain catalytic activity and corrosion resistance, some scholars believe that its ultra-high OER overpotential is the essential reason why it is used as an inert electrode material in the OER catalysis field. Therefore, in order to effectively improve the intrinsic OER catalytic activity of the beta-PbO2 surface catalytic layer, morphology engineering (nanorods, nanosheets, hollow spheres), preparation system optimization strategies (acetic acid system, nitric acid system, sulfamic acid system and methyl sulfonic acid system), preparation processes (electrodeposition, hydrolysis, hydrothermal process and the like) and additional active metal active elements (cobalt, manganese, cerium and the like) and the like methods have emerged. However, the current OER activity of the beta-PbO2 catalytic layer does not meet the requirements of the catalysis field, and it is still necessary to further reduce the OER overpotential.
[0004] The bubble dynamic template electrodeposition can quickly form a three-dimensional porous structure on the substrate, which can serve as a charge transport channel to promote charge transfer and increase the apparent contact area between the electrode material and the electrolyte, thereby promoting the catalytic performance of the catalytic electrode. However, since the bubble dynamic template electrodeposition method is mainly operated at high voltage and large current density for several hours, the mechanical properties of the porous structure formed under this condition are limited, the integrity of the pore wall is poor, and the surface activity is uneven, which leads to poor stability and short service life of the catalytic electrode. SUMMARY
[0005] In view of the problems of poor catalytic activity, short service life and other shortcomings of the traditional hydrometallurgical Pb-(0.5-1.0wt%)Ag anode, which leads to high energy consumption and high production cost in non-ferrous metal electrodeposition process, the present application provides a preparation method of porous tetragonal lead dioxide coating catalytic anode, which adopts linear sweep electrodeposition method to prepare lead-based porous tetragonal lead dioxide electrode material. Through the construction of three-dimensional porous structure, the contact surface area between the catalytic electrode and the electrolyte can be effectively expanded, and in the catalytic process, the charge is transported as the carrier of the structure, which accelerates the charge transport rate and reduces the OER overpotential. Through the coordinated control of voltage window and scanning rate, the porous structure is effectively stabilized, and the service life of the overall electrode material is improved.
[0006] A preparation method of porous tetragonal lead dioxide coating catalytic anode, the specific steps are as follows: (1) removing the oxide layer on the surface of the lead-silver alloy plate to obtain a lead-silver alloy substrate, the lead-silver alloy substrate is soaked in a degreasing agent, then washed with deionized water and dried to obtain a lead-silver alloy substrate electrode; (2) taking the lead-silver alloy substrate electrode as the anode and the stainless steel plate as the cathode, anodic constant current electrodeposition is carried out in a lead oxide alkaline electrolyte, and the anode is washed with deionized water to obtain a lead-silver / orthorhombic lead dioxide electrode; (3) taking the lead-silver / orthorhombic lead dioxide electrode as the working electrode, the stainless steel plate as the counter electrode, and the mercury / mercurous sulfate electrode as the reference electrode, linear sweep electrodeposition is carried out in a methanesulfonic acid-lead methanesulfonate acid system, and the anode is washed with deionized water and dried to obtain a porous tetragonal lead dioxide coating catalytic anode material.
[0007] Preferably, the degreasing agent in step (1) can be selected from commercially available JX-401B cleaning agent.
[0008] Preferably, the lead oxide alkaline electrolyte in step (2) contains 110-125 g / L of sodium hydroxide and 30-36 g / L of lead oxide.
[0009] More preferably, the current density of the anodic constant current electrodeposition in step (2) is 10-16 mA / cm 2 , temperature is 35~50℃, time is 60~120min.
[0010] Preferably, in the methanesulfonic acid-lead methanesulfonate acid system of step (3), the content of methanesulfonic acid is 14-20 g / L, and the content of lead methanesulfonate is 150-180 g / L.
[0011] More preferably, the temperature of the linear scanning electrodeposition in step (3) is 45-65° C., the applied voltage window is 0-4.5 V vs. MSE, and the scanning rate is 10-40 mV / s.
[0012] This invention is based on the preparation principle of a porous tetragonal lead dioxide-coated catalytic anode. The coating catalytic anode is prepared using a linear scanning electrodeposition process, which is an extension of the theory of bubble dynamic template electrodeposition. By varying the voltage window and scan rate to control the oxygen bubble evolution time and diameter, a uniform and dense three-dimensional porous tetragonal lead dioxide coating is produced. The three-dimensional pores shorten the ion diffusion path, reduce concentration polarization, and serve as charge transfer channels to accelerate the charge transfer rate during the anodic oxygen evolution process, thereby enhancing the OER catalytic activity.
[0013] The beneficial effects of the present invention are: (1) The present invention adopts linear scanning anodic constant current electrodeposition to rapidly prepare uniformly distributed three-dimensional porous tetragonal lead dioxide electrode materials by optimizing the voltage window strategy; (2) The present invention increases the apparent contact area between the anode and the electrolyte by constructing a tetragonal lead dioxide coating anode catalytic material with a dense three-dimensional porous structure. At the same time, the pores are used as charge transfer carriers to improve the reaction charge transfer efficiency, thereby improving the catalytic activity of the anode and reducing the energy consumption of the hydrometallurgical electrodeposition process. (3) The porous tetragonal lead dioxide coating anode catalytic material of the present invention has excellent OER catalytic performance and corrosion resistance. In the zinc electrodeposition process, compared with the lead-silver alloy anode, 50mA / cm 2 The OER overpotential can be reduced by 207mV and the self-corrosion current can be increased by 0.087mA / cm at the current density. 2 . BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 The microscopic scanning electron microscope image and corresponding energy spectrum of the catalytic anode based on the porous tetragonal lead dioxide coating of Example 3; Figure 2 This is the XRD pattern of the catalytic anode based on the porous tetragonal lead dioxide coating in Example 3; Figure 3 Linear sweep voltammogram of the lead dioxide coating catalytic anode of Example 1~4 and 50mA / cm 2 The corresponding OER overpotential spectrum; Figure 4 Self-corrosion Tafel test comparison chart of the lead dioxide coating catalytic anode of Example 3 and the anode of the comparative example; Figure 5 Cell voltage test comparison chart of the lead dioxide coating catalytic anode of Example 3 and the anode of the comparative example. DETAILED DESCRIPTION
[0015] The application will be described in further detail below with specific embodiments, but the scope of protection of the application is not limited to the content described.
[0016] Example 1: A preparation method of a porous tetragonal lead dioxide coating catalytic anode, the specific steps are as follows: (1) The lead-silver alloy plate is polished by a grinding machine and sanded to remove the surface oxide layer to obtain a lead-silver alloy substrate; the lead-silver alloy substrate is soaked in a degreasing agent (commercially available JX-401B cleaner) for 4 min to remove oil, then washed with deionized water and dried to obtain a lead-silver alloy substrate electrode without an oxide layer; (2) The lead-silver alloy substrate electrode is used as an anode, and a stainless steel plate is used as a cathode, and anodic constant current electrodeposition is carried out in a lead oxide alkaline electrolyte (containing sodium hydroxide 110 g / L and lead oxide 30 g / L) at a temperature of 35℃ and a current density of 10mA / cm 2 The anode is washed with deionized water to obtain a lead-silver / orthorhombic lead dioxide electrode; (3) The lead-silver / orthorhombic lead dioxide electrode is used as a working electrode, a stainless steel plate is used as a counter electrode, and a mercury / mercurous sulfate electrode is used as a reference electrode, and linear sweep electrodeposition is carried out in a methanesulfonic acid-lead methanesulfonate acid system (containing methanesulfonic acid 14 g / L and lead methanesulfonate 150 g / L) at a temperature of 45℃ (the voltage window applied is 0~1.5V vs. MSE, and the scanning rate is 10mV / s); the anode is washed with deionized water and dried to obtain a porous tetragonal lead dioxide coating catalytic anode material; The main phase of the porous tetragonal lead dioxide coating catalytic anode in this example is tetragonal lead dioxide (β-PbO2), therefore, the lead-silver / orthorhombic lead dioxide surface layer uniformly distributed has a porous structure and the main phase is tetragonal lead dioxide.
[0017] Example 2: A preparation method of a porous tetragonal lead dioxide coating catalytic anode, the specific steps are as follows: (1) Lead-silver alloy plate is polished by sand grinder and sanded by sandpaper to remove surface oxide layer to obtain lead-silver alloy substrate; the lead-silver alloy substrate is soaked in oil removal agent (commercially available JX-401B type cleaning agent) for 8 min, then washed with deionized water, and dried to obtain lead-silver alloy substrate electrode without oxide layer; (2) The lead-silver alloy substrate electrode is used as anode, and stainless steel plate is used as cathode, in lead oxide alkaline electrolyte (the lead oxide alkaline electrolyte contains sodium hydroxide 115 g / L and lead oxide 32 g / L), at temperature 40℃, current density 12 mA / cm 2 , and under anode constant current electrodeposition for 80 min, the anode is washed with deionized water to obtain lead-silver / orthorhombic lead dioxide electrode; (3) The lead-silver / orthorhombic lead dioxide electrode is used as working electrode, stainless steel plate is used as counter electrode, and mercury / mercurous sulfate electrode is used as reference electrode, in methanesulfonic acid-methanesulfonic acid lead acid system (the methanesulfonic acid-methanesulfonic acid lead acid system contains methanesulfonic acid 16 g / L and methanesulfonic acid lead 160 g / L), at temperature 45℃, linear sweep electrodeposition is carried out (voltage window is 0~2.5 V vs. MSE, and scanning rate is 20 mV / s), the anode is washed with deionized water and dried to obtain porous tetragonal lead dioxide coating catalytic anode material; In this embodiment, the main phase of the porous tetragonal lead dioxide coating catalytic anode is tetragonal lead dioxide (β-PbO2), therefore, the lead-silver / orthorhombic lead dioxide surface layer uniformly distributed has porous structure and the main phase is tetragonal lead dioxide.
[0018] Example 3: A preparation method of porous tetragonal lead dioxide coating catalytic anode, the specific steps are as follows: (1) Lead-silver alloy plate is polished by sand grinder and sanded by sandpaper to remove surface oxide layer to obtain lead-silver alloy substrate; the lead-silver alloy substrate is soaked in oil removal agent (commercially available JX-401B type cleaning agent) for 8 min, then washed with deionized water, and dried to obtain lead-silver alloy substrate electrode without oxide layer; (2) The lead-silver alloy substrate electrode is used as anode, and stainless steel plate is used as cathode, in lead oxide alkaline electrolyte (the lead oxide alkaline electrolyte contains sodium hydroxide 115 g / L and lead oxide 32 g / L), at temperature 40℃, current density 12 mA / cm 2 , and under anode constant current electrodeposition for 80 min, the anode is washed with deionized water to obtain lead-silver / orthorhombic lead dioxide electrode; (3) Using a lead-silver / orthorhombic lead dioxide electrode as the working electrode, a stainless steel plate as the counter electrode, and a mercury / mercurous sulfate electrode as the reference electrode, linear scanning electrodeposition was performed at a temperature of 55°C in a methanesulfonic acid-methanesulfonic acid lead acid system (methanesulfonic acid 18 g / L, lead methanesulfonate 170 g / L in the methanesulfonic acid-methanesulfonic acid lead acid system) (the applied voltage window was 0-3.5 V vs. MSE, and the scanning rate was 30 mV / s). The anode was rinsed with deionized water and dried to obtain a porous tetragonal lead dioxide coating catalytic anode material; The microscopic scanning electron microscope image and corresponding energy spectrum of the porous tetragonal lead dioxide coating catalytic anode of this embodiment are shown in FIG. Figure 1 ,from Figure 1 It can be seen that the tetragonal lead dioxide on the surface of the lead-silver / orthorhombic lead dioxide has good uniformity, presents a porous structure, and the inner wall of the pores is smooth. In addition, the corresponding energy spectrum scanning EDS image shows the distribution of lead and oxygen, confirming that the main porous phase is lead oxide. The XRD pattern of the porous tetragonal lead dioxide coating catalytic anode in this embodiment is shown in FIG. Figure 2 ,from Figure 2 It can be seen that this phase only contains orthorhombic lead dioxide (α-PbO2) and tetragonal lead dioxide (β-PbO2), but the main phase is β-PbO2. Therefore, the main phase with a porous structure uniformly distributed on the surface of lead-silver / orthorhombic lead dioxide is tetragonal lead dioxide.
[0019] Example 4: A method for preparing a catalytic anode based on a porous tetragonal lead dioxide coating, the specific steps are as follows: (1) The lead-silver alloy plate was polished by a grinding wheel and sanded with sandpaper to remove the surface oxide layer to obtain a lead-silver alloy matrix; the lead-silver alloy matrix was added to a degreasing agent (commercially available JX-401B type cleaning agent) and soaked for degreasing for 16 minutes, then rinsed with deionized water and dried to obtain a lead-silver alloy matrix electrode without an oxide layer; (2) With the lead-silver alloy substrate electrode as the anode and the stainless steel plate as the cathode, in a lead oxide alkaline electrolyte (the lead oxide alkaline electrolyte contains 125g / L sodium hydroxide and 36g / L lead oxide), at a temperature of 50°C and a current density of 16mA / cm 2 Anodic constant current electrodeposition was performed for 120 min under a quenching condition, and the anode was rinsed with deionized water to obtain a lead-silver / orthorhombic lead dioxide electrode; (3) using lead-silver / orthorhombic lead dioxide electrode as working electrode, stainless steel plate as counter electrode, mercury / mercurous sulfate electrode as reference electrode, linear sweep electrodeposition was carried out in a methanesulfonic acid-methanesulfonic acid lead acidic system (20 g / L of methanesulfonic acid and 180 g / L of methanesulfonic acid lead) at 60℃ (the voltage window was 0-4.5 V vs. MSE, and the scanning rate was 40 mV / s), the anode was washed with deionized water and dried to obtain a porous tetragonal lead dioxide coating catalytic anode material; In the present embodiment, the main phase of the porous tetragonal lead dioxide coating catalytic anode is tetragonal lead dioxide (β-PbO2), therefore, the lead-silver / orthorhombic lead dioxide surface layer uniformly distributed with the porous structure has the main phase of tetragonal lead dioxide; The OER catalytic activity of the porous tetragonal lead dioxide coating catalytic anode in examples 1-4 was detected; The anode of the comparative example and the porous tetragonal lead dioxide coating catalytic anode in examples 1-4 were respectively placed in a zinc electrodeposition test system to carry out linear sweep curve, self-corrosion Tafel curve and cell voltage test. The electrolytic cell type used in the test system was single electrolytic cell, the anode of the comparative example and the porous tetragonal lead dioxide coating catalytic anode in examples 1-4 were respectively used as working electrode, Hg / HgSO4 (MSE) was used as reference electrode, and the pressure aluminum plate was used as counter electrode. The electrolyte in the zinc electrodeposition test system contained 150 g / L of H2SO4 and 50 g / L of ZnSO4. The electrochemical test was mainly linear sweep curve, in which the scanning rate was 5 mV / s, and the applied potential range was 0-2 V vs. MSE; The linear scan spectrum of the lead dioxide coating catalytic anode in examples 1-4 and the OER overpotential spectrum corresponding thereto are shown in 2 Figure 3 ; it can be seen from Figure 3 that under the condition of 50 mA / cm 2 , the OER overpotential corresponding to examples 1-4 showed a trend of first decreasing and then increasing, which was mainly because the voltage window range corresponding to examples 1 and 2 was too narrow, in which oxygen bubbles were just generated, forming tetragonal lead dioxide with uneven diameter distribution of porous structure, resulting in that the OER catalytic activity was not ideal. When the applied voltage (0-3.5 V vs. MSE) and the scanning rate (30 mV / s) of example 3 were reached, the OER overpotential was as low as 804 mV, and the OER catalytic activity was best. When the voltage window and the scanning rate were continuously increased, the amount of oxygen evolution on the surface layer of the catalytic anode was too large, resulting in the collapse of the three-dimensional porous structure of tetragonal lead dioxide, thereby causing the decrease of the OER catalytic activity; The self-corrosion Tafel test of the lead dioxide coating catalytic anode of Example 3 and the comparative anode is shown in the following figure Figure 4 The self-corrosion current of the lead dioxide coating catalytic anode of Example 3 and the comparative anode is 0.108 mA / cm 2 and 0.021 mA / cm 2 , respectively. The difference between the self-corrosion potentials of the two is not large, but the self-corrosion current of the lead dioxide coating catalytic anode of Example 3 is 0.087 mA / cm 2 higher than that of the comparative anode, which indicates that the lead dioxide coating catalytic anode of Example 3 has better corrosion resistance and stability in the same acid test system. The tank voltage test of the lead dioxide coating catalytic anode of Example 3 and the comparative anode is shown in the following figure Figure 5 During the test, the tank voltage of the lead dioxide coating catalytic anode of Example 3 is maintained below that of the comparative anode, and the average tank voltage of the lead dioxide coating catalytic anode of Example 3 is reduced by 140 mV compared with that of the comparative anode, which proves that the lead dioxide coating catalytic anode of Example 3 has good energy-saving effect.
[0020] The specific embodiments of the present application are described in detail above, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the purpose of the present application.
Claims
1. A method for preparing a catalytic anode based on a porous tetragonal lead dioxide coating, characterized in that: The specific steps are as follows: (1) removing the oxide layer on the surface of the lead-silver alloy plate to obtain a lead-silver alloy matrix, adding the lead-silver alloy matrix into a degreasing agent to soak and degrease, then rinsing with deionized water, and drying to obtain a lead-silver alloy matrix electrode; (2) Using a lead-silver alloy substrate electrode as the anode and a stainless steel plate as the cathode, anodic constant current electrodeposition is performed in a lead oxide alkaline electrolyte, and the anode is rinsed with deionized water to obtain a lead-silver / orthorhombic lead dioxide electrode; (3) Linear scanning electrodeposition was carried out in a methanesulfonic acid-lead methanesulfonate acidic system using a lead-silver / orthorhombic lead dioxide electrode as the working electrode, a stainless steel plate as the counter electrode, and a mercury / mercurous sulfate electrode as the reference electrode. The anode was rinsed with deionized water and dried to obtain a porous tetragonal lead dioxide coating catalytic anode material.
2. The method for preparing a catalytic anode based on a porous tetragonal lead dioxide coating according to claim 1, characterized in that: The lead oxide alkaline electrolyte in step (2) contains 110-125 g / L of sodium hydroxide and 30-36 g / L of lead oxide.
3. The method for preparing a catalytic anode based on a porous tetragonal lead dioxide coating according to claim 1 or 2, characterized in that: Step (2) The current density of the anodic constant current electrodeposition is 10~16mA / cm 2 , temperature is 35~50℃, time is 60~120min.
4. The method for preparing a catalytic anode based on a porous tetragonal lead dioxide coating according to claim 1, characterized in that: In step (3), the methanesulfonic acid-lead methanesulfonate acid system contains 14-20 g / L of methanesulfonic acid and 150-180 g / L of lead methanesulfonate.
5. The method for preparing a catalytic anode based on a porous tetragonal lead dioxide coating according to claim 1 or 4, characterized in that: The temperature of the linear scanning electrodeposition in step (3) is 45-65° C., the applied voltage window is 0-4.5 V vs. MSE, and the scanning rate is 10-40 mV / s.