A cobalt-bismuth bimetallic regulated lead-based catalyst, a preparation method and application thereof

Abstract

The application provides a lead-based catalyst regulated by cobalt-bismuth bimetal, a preparation method and application thereof. The catalyst comprises a carrier, and a catalytic material composed of cobalt-doped lead oxide and bismuth oxide is loaded on the surface of the carrier, and the chemical composition of the catalytic material is expressed as Co x Bi y Pb m O n The preparation method of the catalyst comprises the following steps: taking lead salt, cobalt salt and bismuth salt as metal precursors, taking boric acid as a buffer, taking trisodium citrate dihydrate as a complexing agent, and adopting a two-step electrodeposition method to prepare the catalyst. The catalyst can be used for synthesizing sodium borohydride by an electrocatalytic method. In the application, Pb elements are used as main components of electrode materials, a small amount of Co elements and Bi elements are added as additives, and under the joint action of the two additives, the efficiency of the electro-reduction reaction can be effectively improved, and the yield of sodium borohydride is improved.

Description

Technical Field

[0001] This invention belongs to the field of inorganic synthesis and catalytic material preparation technology, and relates to electrochemical hydrogen storage catalysts, specifically to a cobalt-bismuth bimetallic regulated lead-based catalyst, its preparation method and its application. Background Technology

[0002] Sodium borohydride (NaBH4), as a highly efficient chemical hydrogen storage material, produces hydrogen through a catalytic hydrolysis reaction: under the action of a catalyst, NaBH4 reacts with water to generate hydrogen gas and sodium metaborate (NaBO2). This technology is suitable for applications such as small portable power supplies and backup power supplies, and is a promising ready-to-use hydrogen source solution. However, the high price and difficult synthesis of NaBH4 have limited its large-scale development. Traditional industrial synthesis methods, direct reduction methods, and mechano-chemical reduction methods require high-temperature and high-pressure conditions or have complex synthesis steps.

[0003] To avoid the problems associated with traditional methods, NaBO2 solution can be electrolyzed. Sodium metaborate undergoes electroreduction at the cathode, and the formation of sodium borohydride can be detected in the solution using an online electrochemical method. Compared with traditional methods, the electrocatalytic method for producing NaBH4 not only has advantages such as low cost, simple steps, and the ability to be carried out at room temperature and pressure, but also helps to solve the problem of byproduct recovery in the hydrolysis of sodium borohydride to produce hydrogen. However, the yield of sodium borohydride synthesized by the electrocatalytic method is very low, far lower than other methods. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a cobalt-bismuth bimetallic controlled lead-based catalyst, its preparation method, and its application, thereby solving the technical problem of low yield in the electroreduction method for synthesizing sodium borohydride in existing technologies.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A cobalt-bismuth bimetallic regulated lead-based catalyst includes a support, on the surface of which is loaded a catalytic material composed of cobalt-doped lead oxide and bismuth oxide, the chemical composition of which is represented as Co. x Bi y Pb m O nWherein, x represents the mass percentage of cobalt, ranging from 0.001 to 0.01, preferably 0.002, 0.004, 0.006, or 0.008; y represents the mass percentage of bismuth, ranging from 0.05 to 0.2, preferably 0.08, 0.11, 0.14, or 0.17; m represents the mass percentage of lead, ranging from 0.7 to 0.9, preferably 0.72, 0.76, 0.80, 0.84, or 0.88; and n represents the mass percentage of oxygen, ranging from 0.05 to 0.2, preferably 0.08, 0.11, 0.14, or 0.17.

[0007] The present invention also has the following technical features:

[0008] Specifically, the carrier is selected from nickel foam, nickel mesh, stainless steel mesh, copper sheet, copper foam, titanium mesh, titanium felt, titanium foam, carbon cloth, carbon paper, activated carbon, graphene, carbon nanotubes, titanium dioxide, silicon dioxide, or alumina. The thickness of the carrier is 10–1000 μm, specifically 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, or 900 μm; the area of ​​the carrier can be 1–10000 cm². 2 Specifically, it can be 10 cm. 2 50 cm 2 100 cm 2 500cm 2 1000 cm 2 Or 5000 cm 2 .

[0009] This invention also protects a method for preparing a cobalt-bismuth bimetallic regulated lead-based catalyst as described above. This method uses lead salt, cobalt salt, and bismuth salt as metal precursors, boric acid as a buffer, and trisodium citrate dihydrate as a complexing agent, employing a two-step electrodeposition method. The method specifically includes the following steps:

[0010] Step 1, carrier pretreatment: First, immerse the carrier in 0.5 mol / L sulfuric acid solution and ultrasonically clean for 5 min; then immerse the carrier in anhydrous ethanol and ultrasonically clean for 2 min; finally, immerse the carrier in deionized water and ultrasonically clean for 10 min.

[0011] Step two, the first step of electrodeposition: Lead and cobalt salts are dissolved in water to prepare the first electrolyte; the pH of the first electrolyte is adjusted to 3.8–4.0, and then the support is immersed in the first electrolyte. The electrodeposition voltage is set to 0.2–0.5 V, the temperature to 25–45 °C, and the time to 5–40 min. Using a constant voltage DC method in a three-electrode system, a Co-loaded substrate is obtained. x Pb m O n The carrier.

[0012] Step 3, the second electrodeposition: Bismuth salt, boric acid, and trisodium citrate dihydrate are dissolved in water to prepare the second electrolyte; the electrodeposition voltage is set to 2.6–4.0 V, the time to 120–440 s, and the temperature to 20–50 °C; a graphite plate is used as the anode, and a Co-loaded electrode is applied... x Pb m O n The support was used as the cathode, and a cobalt-bismuth bimetallic controlled lead-based catalyst was finally prepared on the cathode.

[0013] Specifically, in the first electrolyte, the lead salt is selected from one or more of lead chloride, lead sulfate, and lead nitrate, and the Co salt is selected from one or more of cobalt chloride, cobalt sulfate, and cobalt nitrate. The concentration of the lead salt is 10–100 mM, preferably 15–35 mM, and most preferably 25 mM; the concentration of the Co salt is 5–50 mM, preferably 5–25 mM, and most preferably 25 mM.

[0014] Specifically, in the second electrolyte, the bismuth salt is selected from one or more of bismuth nitrate, bismuth chloride, and bismuth sulfate. The concentration of the bismuth salt is 1–20 mM, preferably 3–15 mM, and most preferably 3 mM. The concentration of boric acid is 20–70 mM, preferably 20–40 mM, and most preferably 27 mM. The concentration of trisodium citrate dihydrate is 7–87 mM, preferably 20–80 mM, and most preferably 27 mM.

[0015] Specifically, the volumes of the first electrolyte and the second electrolyte are 10 to 5000 mL, preferably 10 to 100 mL, and most preferably 40 to 50 mL.

[0016] This invention also protects the application of the cobalt-bismuth bimetallic regulated lead-based catalyst described above in the electrocatalytic synthesis of sodium borohydride. This application includes: using the cobalt-bismuth bimetallic regulated lead-based catalyst as the working electrode, a graphite rod as the counter electrode, and mercury / mercuric oxide as the reference electrode to electrolyze an alkaline sodium metaborate solution.

[0017] Specifically, the sodium metaborate alkaline solution contains 0.1–3 M sodium metaborate and 0.5–5 M sodium hydroxide; preferably, the concentration of sodium metaborate is 0.3–2.0 M, and most preferably 0.5 M; preferably, the concentration of sodium hydroxide is 0.5–2 M, and most preferably 1.0 M.

[0018] Specifically, the electrolysis conditions include: an electrolysis potential of 0.5–1.5V, preferably 0.8–1.2V, and most preferably 1.0V; an electrolysis time of 0.5–8 h; and an electrolysis temperature of 15–35℃, preferably 25℃.

[0019] Compared with the prior art, the present invention has the following technical effects:

[0020] (I) This invention uses Pb as the main component of the electrode material, with small amounts of Co and Bi added as auxiliary agents. Pb effectively suppresses the hydrogen evolution side reaction during water electrolysis at the cathode, accelerating the kinetic rate of the electroreduction reaction. Bi, as an auxiliary agent, significantly promotes the detachment of B from the hydroxyl group to form the positively charged active center of B. Co, as another auxiliary agent, provides more adsorbed hydrogen sources for the formation of BH. Under the combined action of these two auxiliary agents, the efficiency of the electroreduction reaction is effectively improved, thereby increasing the yield of sodium borohydride.

[0021] (II) The catalyst prepared by the present invention is a composite structure composed of fibers and sheets, which has a high specific surface area, can fully expose active sites, and improve the electrocatalytic activity of the material.

[0022] (III) The preparation method of the present invention employs a two-step electrodeposition process, which is simple, easy to implement, and operates under mild conditions. Furthermore, the raw materials do not involve precious metals, making them readily available and relatively inexpensive.

[0023] (IV) The technical solution of this invention uses a two-step electrodeposition method to prepare Co. x Bi y Pb m O n The / NF catalyst exhibited excellent electrocatalytic activity when used as a cathode material in a sodium metaborate electroreduction device. After 0.5 h of electrolysis, the highest oxidation peak current density measured by online electrochemical method reached 1.061 mA·cm⁻¹. -2 . Attached Figure Description

[0024] Figure 1 Cyclic voltammetry curves of sodium metaborate alkaline solution after electrolysis with different metal sheets as cathode materials.

[0025] Figure 2 The apparatus used in the second electrodeposition step of this invention is shown.Figure 2 The meanings of the various labels are as follows: 1-peristaltic pump, 2-electroplating tank, 3-power supply.

[0026] Figure 3 Co prepared in Example 1 x Bi y Pb m O n Scanning electron microscope image of / NF catalyst.

[0027] Figure 4 Co prepared in Example 1 x Bi y Pb m O n X-ray diffraction results of / NF catalyst.

[0028] Figure 5 Co prepared in Example 1 x Bi y Pb m O n Elemental surface scans of / NF catalysts obtained by high-resolution transmission electron microscopy.

[0029] Figure 6 The two-chamber electrolytic cell used for the catalytic synthesis of sodium borohydride in this invention is shown.

[0030] Figure 7 Co prepared in Example 1 x Bi y Pb m O n The volt-ampere characteristic curves of / NF catalyst as cathode material were tested.

[0031] Figure 8 Co prepared in Example 2 x Bi y Pb m O n Oxidation peak current density tested using / NF catalyst as cathode material.

[0032] Figure 9 Co prepared in Example 3 x Bi y Pb m O n Oxidation peak current density tested using / NF catalyst as cathode material.

[0033] Figure 10 Co prepared in Example 1 x Bi y Pb m O nOxidation peak current density tested using / NF catalyst as cathode material (according to the apparatus and conditions of Examples 11 and 12).

[0034] Figure 11 Co prepared in Example 1 x Bi y Pb m O n Oxidation peak current density tested using / NF catalyst as cathode material (according to the apparatus and conditions of Examples 11 and 13).

[0035] The specific content of the present invention will be further explained in detail below with reference to the embodiments. Detailed Implementation

[0036] It should be noted that, unless otherwise specified, all reaction materials and testing methods in this invention are those known in the art. For example, the online electrochemical method is based on the literature "Study on the Synthesis of Sodium Borohydride by Electrolysis of Sodium Metaborate" (Zhao Jiaxiong, Chongqing University, 2008).

[0037] In their previous work, the inventors of this invention discovered through research on several high hydrogen evolution potential materials (Pb, Sn, Zn, Cd, Cu sheets, etc.) that Pb-based materials exhibit good selectivity for the electroreduction of sodium metaborate, such as... Figure 1 Only after electrolyzing sodium metaborate solution with lead sheets can the presence of sodium borohydride in the solution be detected by an online electrochemical method. Based on the above results, this invention further develops a cobalt-bismuth bimetallic regulated lead-based catalyst.

[0038] Following the above technical solutions, specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0039] Example 1:

[0040] This embodiment presents a lead-based catalyst regulated by cobalt-bismuth bimetal (Co). x Bi y Pb m O n A method for preparing an NF catalyst, the method specifically includes the following steps:

[0041] Step 1, carrier pretreatment: Using nickel foam as a carrier with a size of 1*1.5 cm, immerse it in a beaker containing 0.5 mol / L sulfuric acid solution and sonicate for 5 min to remove surface oil; then immerse it in anhydrous ethanol and sonicate for 2 min to remove surface organic matter; finally, place it in deionized water and sonicate for 10 min to remove other impurities.

[0042] Step 2, the first step of electrodeposition: Cobalt chloride and lead chloride were dissolved in 50 mL of water to prepare the electrolyte, both at a concentration of 25 mM. A trace amount of dilute hydrochloric acid was added to adjust the pH to 3.9. Then, using an electrochemical workstation in a three-electrode system (the two pieces of nickel foam pretreated in Step 1 were the working electrode and the counter electrode, respectively, and a saturated calomel electrode was used as the reference electrode), a 1*1 cm portion of the nickel foam was immersed in the electrolyte. The electrodeposition voltage was set to 0.25 V (vs. SCE), the temperature to 35℃, and the time to 30 min. Co was obtained on the counter electrode using a constant voltage DC method. x Pb m O n / NF catalyst.

[0043] Step 3, the second step of electrodeposition: Bismuth nitrate, boric acid, and trisodium citrate dihydrate were dissolved in 40 mL of water to prepare the electrolyte, with concentrations of 3 mM, 27 mM, and 65 mM, respectively. A high-frequency rectifier was used as the power source, and the electrodeposition parameters were set as follows: electrodeposition voltage 3 V, time 360 ​​s, and temperature 35℃. A graphite plate was used as the anode, and Co... x Pb m O n / NF catalyst is used as the cathode, and Co is finally obtained at the cathode. x Bi y Pb m O n / NF catalyst, device such as Figure 2 As shown, it includes a peristaltic pump (1), an electroplating tank (2), and a power supply (3).

[0044] In this embodiment, scanning electron microscopy was used to observe Co. x Bi y Pb m O n The structure of / NF catalysts, such as Figure 3 As shown, the catalyst has a composite structure of fibers and sheets. Figure 4 X-ray diffraction results showed that the catalyst had a crystal structure of Pb and PbO (PbO being the main component responsible for catalytic activity). Figure 5 Selected area EDS (Electron Sweep) results from medium- and high-resolution transmission electron microscopy (TEM) demonstrate that the four elements Co, Bi, Pb, and O exhibit a highly uniform spatial distribution in the catalyst.

[0045] Example 2:

[0046] This embodiment provides a Co x Pb m O nThe preparation method of / NF catalyst is basically the same as that in Example 1, except that: in step two, the concentration of cobalt chloride is 0 mM, 5 mM, 10 mM, and 15 mM; and step three is not performed.

[0047] Example 3:

[0048] This embodiment presents a lead-based catalyst regulated by cobalt-bismuth bimetal (Co). x Bi y Pb m O n The preparation method of bismuth nitrate catalyst (NF catalyst) is basically the same as that in Example 1, except that in step 3, the concentration of bismuth nitrate is 0 mM, 5 mM, 10 mM, 15 mM, and 20 mM.

[0049] Example 4:

[0050] This embodiment provides a Co x Bi y Pb m O n The preparation method of / NF catalyst is basically the same as that in Example 1, except that in step two, the pH of the electrolyte is 3.80, 3.82, 3.84, 3.86, 3.88, 3.92, 3.94, 3.96, and 3.98.

[0051] Example 5:

[0052] This embodiment provides a Co x Bi y Pb m O n The preparation method of / NF catalyst is basically the same as that in Example 1, except that in step two, the electrodeposition voltage is 0.20 V, 0.30 V, 0.35 V, 0.40 V, 0.45 V, and 0.50 V (vs. SCE).

[0053] Example 6:

[0054] This embodiment provides a Co x Bi y Pb m O n The preparation method of / NF catalyst is basically the same as that in Example 1, except that in step two, the electrodeposition temperature is 25℃, 30℃, 40℃, 45℃, and 50℃.

[0055] Example 7:

[0056] This embodiment provides a Co x Bi y Pb m On The preparation method of / NF catalyst is basically the same as that in Example 1, except that in step two, the electrodeposition time is 5 min, 10 min, 15 min, 20 min, 25 min, 35 min, and 40 min.

[0057] Example 8:

[0058] This embodiment provides a Co x Bi y Pb m O n The preparation method of / NF catalyst is basically the same as that in Example 1, except that in step three, the electrodeposition voltage is 2.6 V, 2.8 V, 3.2 V, 3.4 V, 3.6 V, 3.8 V, and 4.0 V.

[0059] Example 9:

[0060] This embodiment provides a Co x Bi y Pb m O n The preparation method of / NF catalyst is basically the same as that in Example 1, except that in step three, the electrodeposition time is 120 s, 160 s, 200 s, 240 s, 280 s, 320 s, 400 s, and 440 s.

[0061] Example 10:

[0062] This embodiment provides a Co x Bi y Pb m O n The preparation method of / NF catalyst is basically the same as that in Example 1, except that in step three, the electrodeposition temperature is 20, 25, 30, 40, 45, or 50 °C.

[0063] Example 11:

[0064] This embodiment illustrates the application of the lead-based catalysts prepared in Examples 1 to 3 in the electrocatalytic synthesis of sodium borohydride; the application includes: in, for example... Figure 6Sodium metaborate is electrolyzed in a two-chamber electrolytic cell. The electrolytic cell is H-shaped, with the left side being the cathode chamber containing 40 mL of a mixture of 1M NaOH and 0.5M NaBO2. The right side is the anode chamber containing 40 mL of 1M NaOH solution. The Nafion-117 cation exchange membrane is clamped with a gasket and then fixed to the connection between the two chambers with a clip. The catalyst in the cathode chamber serves as the working electrode, and Hg / HgO serves as the reference electrode. The graphite rod in the anode chamber serves as the counter electrode. The electrolysis conditions are 25℃ and a constant potential of -1 V (vs. Hg / HgO) for 0.5 h.

[0065] Example 12:

[0066] This embodiment describes the application of the lead-based catalyst prepared in Example 1 in the electrocatalytic synthesis of sodium borohydride; the application is basically the same as that in Example 11, except that the concentration of NaBO2 is 0.3, 1.0, 1.5, and 2.0 M.

[0067] Example 13:

[0068] This embodiment describes the application of the lead-based catalyst prepared in Example 1 in the electrocatalytic synthesis of sodium borohydride; the application is basically the same as that in Example 11, except that the electrolysis potential is -0.8, -0.9, -1.1, -1.2 V (vs. Hg / HgO).

[0069] Effect verification:

[0070] The amount of NaBH4 generated was determined by an online electrochemical method. The specific procedure is as follows: the solution in the cathode chamber after 0.5 h of electrolysis was used as the electrolyte, and the reaction was carried out in a three-electrode system. A gold sheet electrode was used as the working electrode, Hg / HgO as the reference electrode, and a graphite rod as the counter electrode. The potential scan window was -0.8 to 0 V, and the scan rate was typically 50 mV / s. Since NaBH4... - The electro-oxidation behavior on the gold electrode (approximately -0.4 V) can be analyzed using the oxidation peak current density obtained from LSV scanning to determine the BH4 generated in the cathode chamber. - The higher the concentration and peak current density of BH4, the better. - The higher the concentration.

[0071] like Figure 7 As shown, the Co prepared in Example 1 x Bi y Pb m O n Using NF catalyst as the cathode material, NaBO2 solution was electrolyzed according to the apparatus and conditions of Example 11. The LSV curve was then measured using a gold electrode, revealing that the oxidation peak current density reached 1.061 mA·cm⁻¹. -2 .

[0072] like Figure 8 As shown, the Co prepared in Example 2 x Bi y Pb m O n Using the / NF catalyst as the cathode material, NaBO2 solution was electrolyzed according to the apparatus and conditions of Example 11. The LSV curve was then obtained by testing with a gold electrode. It was observed that as the concentration of Co ions in the electrolyte gradually increased, the oxidation peak current density gradually increased in the performance test. This is because Co is an active element for hydrogen evolution in water electrolysis. The appropriate addition can provide an additional source of adsorbed hydrogen for the electroreduction reaction of sodium metaborate, thus accelerating the kinetic process of the electroreduction reaction.

[0073] like Figure 9 As shown, the Co prepared in Example 3 x Bi y Pb m O n Using the / NF catalyst as the cathode material, NaBO2 solution was electrolyzed under the apparatus and conditions of Example 11. LSV curves were then obtained using a gold electrode. It was observed that the introduction of Bi significantly increased the oxidation peak current density of the product, suggesting an increase in the yield of sodium borohydride. This is mainly due to the fact that the introduction of Bi significantly promotes the detachment of B from the hydroxyl group to form more positively charged active sites for B, which is beneficial for subsequent reactions.

[0074] Co prepared using Examples 4-10 x Bi y Pb m O n Using / NF catalyst as the cathode material, NaBO2 solution was electrolyzed according to the apparatus and conditions of Example 11. LSV curves were then obtained using a gold electrode. Experimental results showed that in step two, the electrolyte pH range of 3.80–3.98 significantly affected the performance of the final catalyst, with pH values ​​of 3.88 and 3.92 being preferred conditions. The electrodeposition voltage range of 0.20–0.50 V significantly affected the performance of the final catalyst, with 0.3 V being a preferred condition. The electrodeposition temperature range of 25–50 °C had little effect on the performance of the final catalyst, with 25 and 40 °C being preferred conditions. The electrodeposition time range of 5–40 min significantly affected the performance of the final catalyst, with 35 and 40 min being preferred conditions. In step three, the electrodeposition voltage within the range of 2.6–4.0 V has a significant impact on the performance of the final catalyst, with 3.2 and 3.6 V being the preferred conditions; the electrodeposition time within the range of 120–440 s has a significant impact on the performance of the final catalyst, with 400 s being the preferred condition; and the electrodeposition temperature within the range of 20–50 °C has little impact on the performance of the final catalyst, with 45 °C being the preferred condition.

[0075] like Figure 10 As shown, the Co prepared in Example 1 x Bi y Pb m O n Using NF catalyst as the cathode material, and electrolyzing NaBO2 solution according to the apparatus and conditions of Examples 11 and 12, it was found that the oxidation peak current density measured by the gold electrode was the highest at a NaBO2 concentration of 0.5 M, which was 0.960 mA·cm⁻¹. -2 This indicates that BO2 - A moderate increase in concentration is beneficial to the reaction, but excessively high concentrations will cause BO2 to... - Accumulation on the electrode surface hinders electron transfer and the product BH4. - The spread of.

[0076] like Figure 11 As shown, the Co prepared in Example 3 x Bi y Pb m O n Using NF catalyst as the cathode material, and electrolyzing NaBO2 solution according to the apparatus and conditions of Examples 11 and 13, it was found that the oxidation peak current density measured by the gold electrode was the highest at an electrolysis potential of -0.9 V, which was 1.061 mA·cm⁻¹. -2 This is mainly because when the applied potential enters the potential range where the electroreduction reaction and the hydrogen evolution reaction (side reaction) coexist, the electron transport channel will activate both reactions simultaneously, causing the HER reaction to compete with the electroreduction reaction. Therefore, optimizing the potential window to determine the optimal electrolysis potential range, allowing the electroreduction reaction to dominate, is particularly important for improving the yield of sodium borohydride.

Claims

1. A method for preparing a cobalt-bismuth bimetallic regulated lead-based catalyst, characterized in that, This method uses lead salts, cobalt salts, and bismuth salts as metal precursors, boric acid as a buffer, and trisodium citrate dihydrate as a complexing agent, and is prepared using a two-step electrodeposition method. The method specifically includes the following steps: Step 1, carrier pretreatment: First, immerse the carrier in 0.5 mol / L sulfuric acid solution and ultrasonically clean for 5 min; then immerse the carrier in anhydrous ethanol and ultrasonically clean for 2 min; finally, immerse the carrier in deionized water and ultrasonically clean for 10 min. Step two, the first step of electrodeposition: Lead and cobalt salts are dissolved in water to prepare the first electrolyte; the pH of the first electrolyte is adjusted to 3.8–4.0, and then the support is immersed in the first electrolyte. The electrodeposition voltage is set to 0.2–0.5 V, the temperature to 25–45 °C, and the time to 5–40 min. Using a constant voltage DC method in a three-electrode system, a Co-loaded substrate is obtained. x Pb m O n The carrier; Step 3, the second electrodeposition: Bismuth salt, boric acid, and trisodium citrate dihydrate are dissolved in water to prepare the second electrolyte; the electrodeposition voltage is set to 2.6–4.0 V, the time to 120–440 s, and the temperature to 20–50 °C; a graphite plate is used as the anode, and a Co-loaded electrode is applied... x Pb m O n The support was used as the cathode, and a cobalt-bismuth bimetallic controlled lead-based catalyst was finally prepared on the cathode.

2. The method for preparing the cobalt-bismuth bimetallic regulated lead-based catalyst as described in claim 1, characterized in that, In the first electrolyte, the lead salt is selected from one or more of lead chloride, lead sulfate, and lead nitrate, and the Co salt is selected from one or more of cobalt chloride, cobalt sulfate, and cobalt nitrate; in the second electrolyte, the bismuth salt is selected from one or more of bismuth nitrate, bismuth chloride, and bismuth sulfate.

3. The method for preparing the cobalt-bismuth bimetallic regulated lead-based catalyst as described in claim 1, characterized in that, In the first electrolyte, the concentration of lead salt is 10–100 mM and the concentration of Co salt is 5–50 mM; in the second electrolyte, the concentration of bismuth salt is 1–20 mM.

4. The method for preparing the cobalt-bismuth bimetallic regulated lead-based catalyst as described in claim 1, characterized in that, In the second electrolyte, the concentration of boric acid is 20–70 mM, and the concentration of trisodium citrate dihydrate is 7–87 mM.

5. A cobalt-bismuth bimetallic regulated lead-based catalyst prepared by the preparation method according to any one of claims 1 to 4, characterized in that, This includes a support, the surface of which is loaded with cobalt-doped lead oxide and bismuth oxide, the chemical composition of which is represented as Co. x Bi y Pb m O n Where x represents the mass percentage of cobalt, ranging from 0.001 to 0.01; y represents the mass percentage of bismuth, ranging from 0.05 to 0.2; m represents the mass percentage of lead, ranging from 0.7 to 0.9; and n represents the mass percentage of oxygen, ranging from 0.05 to 0.

2.

6. The cobalt-bismuth bimetallic regulated lead-based catalyst as described in claim 5, characterized in that, The carrier is selected from one of the following: nickel foam, nickel mesh, stainless steel mesh, copper sheet, copper foam, titanium mesh, titanium felt, titanium foam, carbon cloth, carbon paper, activated carbon, graphene, carbon nanotubes, titanium dioxide, silicon dioxide, or alumina; the thickness of the carrier is 10–1000 μm, and the area is 1–10000 cm². 2 .

7. The application of the cobalt-bismuth bimetallic regulated lead-based catalyst as described in claim 5 in the electrocatalytic synthesis of sodium borohydride.

8. The application as described in claim 7, characterized in that, The application includes: using a lead-based catalyst regulated by cobalt-bismuth bimetal as the working electrode to electrolyze an alkaline solution of sodium metaborate; the electrolysis conditions include: an electrolysis potential of 0.5–1.5 V, an electrolysis time of 0.5–8 h, and an electrolysis temperature of 15–35 °C.

9. The application as described in claim 8, characterized in that, The alkaline sodium metaborate solution contains 0.1–3 M sodium metaborate and 0.5–5 M sodium hydroxide.

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