Composite chlorine evolution electrode and preparation method and application thereof

Abstract

The invention relates to a composite chlorine evolution electrode and a preparation method and application thereof, and the preparation method comprises the following steps: placing a titanium-based material as a carrier in an anode, carrying out electro-deposition in a cobalt-ytterbium mixed salt solution, and calcining to obtain the composite chlorine evolution electrode. According to the composite chlorine evolution electrode provided by the invention, the active material simultaneously contains the Co element and the Yb element, the introduced Yb element can generate a synergistic effect with the Co element, the charge distribution around the Co element is adjusted, the conductivity of the composite chlorine evolution electrode is improved, the adjustment of the charge distribution and the improvement of the conductivity jointly optimize a chlorine evolution reaction mechanism, and the catalytic chlorine evolution activity is enhanced; the preparation method disclosed by the invention is simple, quick, green and efficient, low in raw material cost, low in manufacturing cost and suitable for large-scale production, and shows the potential of industrial large-scale application.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electrochemistry and energy technology, and particularly relates to a composite chlorine evolution electrode, a preparation method and application thereof. BACKGROUND

[0002] Chlorine is one of the important basic raw materials in chemical industry, and is widely used in the production of pharmaceuticals, plastics, disinfectants and bleaching agents. In the traditional method of producing chlorine, i.e. chlor-alkali method, chlorine, hydrogen and sodium hydroxide are produced by electrolyzing sodium chloride (NaCl) solution. The electro-catalytic chlorine evolution process (CER) is the core reaction in this method, and the performance of the electrode directly affects the electrolysis efficiency and product quality. Therefore, it is of great significance to improve the performance of the electro-catalytic chlorine evolution electrode for improving energy efficiency and reducing cost.

[0003] The basic principle of chlor-alkali electrolysis is that oxidation reaction occurs at the anode: 2Cl - → Cl2↑ + 2e - , and reduction reaction occurs at the cathode: 2H + + 2e - → H2↑. Because the reaction is in aqueous solution, the oxygen evolution reaction (2H2O→O2↑+4H + + 4e - U 0 OER = 1.23 V vs RHE) is the main competing reaction of chlorine evolution reaction (2Cl - → Cl2↑ + 2e - U 0 CER = 1.36 V vs SHE). The chlorine evolution reaction requires a high overpotential (usually above 1.5 V), so improving the catalytic efficiency of the chlorine evolution reaction is a challenge.

[0004] Current research mainly focuses on improving the activity, stability and corrosion resistance of electrode materials. The commonly used DSA electrode (i.e. titanium ruthenium iridium electrode) has excellent stability and catalytic performance, but it is loaded with RuO2, IrO2 and other noble metal oxides, which not only has high cost, but also the stability and chlorine evolution efficiency of the electrode are often difficult to meet the requirements under high current density, long-term use and corrosion environment. Therefore, it is particularly important to develop electrode materials with higher chlorine evolution activity, corrosion resistance and longer service life.

[0005] Therefore, how to provide an electrode material with higher chlorine evolution activity, better corrosion resistance and longer service life for chlorine evolution process has become a technical problem to be solved at present. SUMMARY

[0006] To solve the above technical problems, the application provides a composite chlorine evolution electrode, a preparation method and application thereof. The composite chlorine evolution electrode provided by the application contains Co elements and Yb elements in the active material. The introduction of Yb elements can produce a synergistic effect with Co elements, adjust the charge distribution around Co elements, and improve the conductivity of the composite chlorine evolution electrode, thereby jointly optimizing the chlorine evolution reaction mechanism, enhancing the catalytic chlorine evolution activity.

[0007] To achieve the above purpose, the application adopts the following technical solutions:

[0008] In a first aspect, the application provides a preparation method of a composite chlorine evolution electrode, which comprises the following steps:

[0009] The titanium-based material is placed as a carrier in the anode, and is subjected to electrodeposition in a cobalt-ytterbium mixed salt solution, and is calcined to obtain the composite chlorine evolution electrode.

[0010] In the application, the titanium-based material is subjected to electrodeposition in a cobalt-ytterbium mixed salt solution. The active material of the obtained composite chlorine evolution electrode has a synergistic effect between Co elements and Yb elements. The Yb elements can adjust the charge distribution around the Co elements, can optimize the adsorption energy of the reaction intermediates, can enhance the interaction between the chlorine ions and the composite chlorine evolution electrode, can improve the reaction activity, and can be more conducive to the chlorine evolution reaction. At the same time, the Yb elements can further improve the conductivity of the composite chlorine evolution electrode. The adjustment of the charge distribution and the improvement of the conductivity jointly enhance the catalytic chlorine evolution activity of the composite chlorine evolution electrode.

[0011] In addition, the electrodeposition method of the application is suitable for the preparation of composite chlorine evolution electrodes of any size, and has the advantages of simplicity, environmental protection and low cost, and has great commercial application potential. The raw materials used are also conventional materials in the field, which are widely available and easy to obtain.

[0012] As a preferred technical solution of the application, in the cobalt-ytterbium mixed salt solution, the molar ratio of cobalt salt to ytterbium salt is 1:(0.25-4), for example, 1:0.25, 1:0.5, 1:0.75, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5 or 1:4, etc.

[0013] In the application, the molar ratio of cobalt salt to ytterbium salt is controlled to be 1:(0.25-4), and the obtained composite chlorine evolution electrode can achieve the best catalytic effect. If the content of ytterbium salt is too low, the synergistic effect with cobalt elements will be reduced, and the catalytic performance of the composite chlorine evolution electrode will be reduced. If the content of ytterbium salt is too high, the active area of cobalt elements will be covered, the conductivity will be reduced, the diffusion will be blocked, and the overall activity of the composite chlorine evolution electrode will be reduced.

[0014] Preferably, the total mass concentration of cobalt salt and ytterbium salt in the cobalt-ytterbium mixed salt solution is 10 g / L to 15 g / L, such as 10 g / L, 11 g / L, 12 g / L, 13 g / L, 14 g / L or 15 g / L, etc.

[0015] As a preferred technical solution of the present application, the titanium-based carrier comprises a pretreated foam titanium.

[0016] In the present application, the pretreated foam titanium is used as the titanium-based carrier, which has a porous structure and a high specific surface area, and can provide sufficient loading sites.

[0017] Preferably, the preparation step of the pretreated foam titanium comprises: alkali washing the foam titanium, then immersing it in an acid solution for acid etching, and obtaining the pretreated foam titanium after cleaning.

[0018] Preferably, the alkali solution used in the alkali washing comprises a sodium hydroxide solution.

[0019] Preferably, the concentration of the alkali solution used in the alkali washing is 0.05 g / mL to 0.25 g / mL, such as 0.05 g / mL, 0.1 g / mL, 0.15 g / mL, 0.2 g / mL or 0.25 g / mL, etc.

[0020] Preferably, the alkali washing is performed by oil bath heating.

[0021] Preferably, the temperature of the oil bath heating is 60°C to 100°C, such as 60°C, 70°C, 80°C, 90°C or 100°C, etc.

[0022] Preferably, the time of the oil bath heating is 40 min to 70 min, such as 40 min, 50 min, 60 min or 70 min, etc.

[0023] Preferably, the acid solution comprises an oxalic acid solution.

[0024] Preferably, the concentration of the acid solution is 0.05 g / mL to 0.25 g / mL, such as 0.05 g / mL, 0.1 g / mL, 0.15 g / mL, 0.2 g / mL or 0.25 g / mL, etc.

[0025] Preferably, the temperature of the acid etching is 60°C to 100°C, such as 60°C, 70°C, 80°C, 90°C or 100°C, etc.

[0026] Preferably, the time of the acid etching is 100 min to 150 min, such as 100 min, 110 min, 120 min, 130 min, 140 min or 150 min, etc.

[0027] Preferably, the cleaning comprises cleaning with deionized water.

[0028] Preferably, the cobalt salt comprises any one or a combination of at least two of cobalt nitrate, cobalt chloride, cobalt sulfate or cobalt acetate, preferably cobalt chloride and / or cobalt nitrate.

[0029] Preferably, the ytterbium salt comprises any one or a combination of at least two of ytterbium nitrate, ytterbium chloride, ytterbium sulfate or ytterbium acetate, preferably ytterbium chloride and / or ytterbium nitrate.

[0030] As a preferred technical solution of the present application, the calcination temperature is 400℃-550℃, for example 400℃, 420℃, 450℃, 480℃, 500℃, 520℃ or 550℃, etc.

[0031] The present application further regulates the calcination temperature to be 400℃-550℃, and the obtained composite chlorine evolution electrode has a complete structure and better chlorine evolution activity. If the calcination temperature is too high, the crystal structure of the active material in the composite chlorine evolution electrode will be damaged, and the catalytic active sites will be reduced. If the calcination temperature is too low, the crystal structure of the active material is not complete, and the catalytic active sites are reduced. Therefore, too high or too low will result in reduced chlorine evolution activity.

[0032] Preferably, the calcination time is 1.5h-2.5h, for example 1.5h, 1.6h, 1.7h, 1.8h, 1.9h, 2.0h, 2.1h, 2.2h, 2.3h, 2.4h or 2.5h, etc.

[0033] As a preferred technical solution of the present application, the calcination is carried out in an inert atmosphere.

[0034] The present application regulates the calcination to be carried out in an inert atmosphere. If the calcination is carried out in air or under oxygen-containing conditions, other impurity phases generated by the doping reaction in the active material in the composite chlorine evolution electrode, such as cobalt tritelluride, will have a greater impact on the chlorine evolution activity, resulting in reduced chlorine evolution activity.

[0035] Preferably, the gas used in the inert atmosphere comprises argon.

[0036] As a preferred technical solution of the present application, the current density of the electrodeposition is 20mA / cm 2 -30mA / cm 2 , for example 20mA / cm 2 , 22mA / cm 2 , 24mA / cm 2 , 26mA / cm 2 , 28mA / cm 2 or 30mA / cm 2 , etc.

[0037] Preferably, the temperature of the electrodeposition is 25-35℃, such as 25℃, 28℃, 30℃, 32℃ or 35℃, etc.

[0038] Preferably, the time of the electrodeposition is 30-60min, such as 30min, 35min, 40min, 45min, 50min, 55min or 60min, etc.

[0039] In the present application, the time of the electrodeposition is 30-60min, which can regulate the content of Co element and Yb element in the active material of the composite chlorine evolution electrode, so that the catalytic performance of the composite chlorine evolution electrode is more optimal, and the chlorine evolution activity is more optimal. If the time of the electrodeposition is too long, the content of Co element and Yb element is too much, which will result in excessive loading, catalyst accumulation and reduced active area. If the time of the electrodeposition is too short, the content of Co element and Yb element is too less, which will result in insufficient loading and reduced catalytic effect.

[0040] As a preferred technical solution of the present application, the preparation method comprises the following steps:

[0041] The foamed titanium is subjected to alkali washing by using an alkali solution with a concentration of 0.05-0.25g / mL and oil bath heating, the temperature of the oil bath heating is 60-100℃, the time is 40-70min, then the foamed titanium is immersed in an acid solution with a concentration of 0.05-0.25g / mL and subjected to acid washing and etching at a temperature of 60-100℃ for 100-150min, and then the pretreated foamed titanium is obtained by cleaning with deionized water, and the pretreated foamed titanium is used as a carrier and placed in an anode in a cobalt-erbium mixed salt solution, and electrodeposition is carried out at a current density of 20-30mA / cm 2 ~ 30mA / cm 2 ~ 30mA / cm

[0042] The foamed titanium is subjected to alkali washing by using an alkali solution with a concentration of 0.05-0.25g / mL and oil bath heating, the temperature of the oil bath heating is 60-100℃, the time is 40-70min, then the foamed titanium is immersed in an acid solution with a concentration of 0.05-0.25g / mL and subjected to acid washing and etching at a temperature of 60-100℃ for 100-150min, and then the pretreated foamed titanium is obtained by cleaning with deionized water, and the pretreated foamed titanium is used as a carrier and placed in an anode in a cobalt-erbium mixed salt solution, and electrodeposition is carried out at a current density of 20-30mA / cm

[0043] In the present application, the time of the electrodeposition is 30-60min, which can regulate the content of Co element and Yb element in the active material of the composite chlorine evolution electrode, so that the catalytic performance of the composite chlorine evolution electrode is more optimal, and the chlorine evolution activity is more optimal. If the time of the electrodeposition is too long, the content of Co element and Yb element is too much, which will result in excessive loading, catalyst accumulation and reduced active area. If the time of the electrodeposition is too short, the content of Co element and Yb element is too less, which will result in insufficient loading and reduced catalytic effect.

[0044] As a preferred technical solution of the present application, the preparation method comprises the following steps:

[0045] Preferably, the Co-containing oxide comprises CoO.

[0046] Preferably, the Yb-containing oxide comprises Yb2O3.

[0047] In the composite chlorine-evolving electrode in the present application, the remaining components are titanium-based materials in addition to the Co-containing oxide and the Yb-containing oxide.

[0048] As a preferred technical solution of the present application, the Co element accounts for 10wt% to 15wt% of the total mass percentage of the composite chlorine-evolving electrode, such as 10wt%, 11wt%, 12wt%, 13wt%, 14wt% or 15wt%, etc.

[0049] Preferably, the Yb element accounts for 5wt% to 45wt% of the total mass percentage of the composite chlorine-evolving electrode, such as 5wt%, 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt% or 45wt%, etc.

[0050] In a third aspect, the present application also provides an application of the composite chlorine-evolving electrode. The composite chlorine-evolving electrode prepared by the preparation method in the first aspect or the composite chlorine-evolving electrode in the second aspect is applied to the treatment of chlorine ions in chlorinated wastewater and / or the production of chlorine gas by electrolyzing brine.

[0051] Compared with the prior art, the present application has at least the following beneficial effects:

[0052] (1) The composite chlorine-evolving electrode provided by the present application has excellent electrocatalytic chlorine-evolving performance. The introduction of Yb element (in the form of Yb2O3) can produce a synergistic effect with Co element (in the form of CoO) to jointly optimize the chlorine-evolving reaction mechanism, and the composite chlorine-evolving electrode can be widely applied to the production of industrial products such as hydrogen gas, chlorine gas and sodium hydroxide by electrocatalytically decomposing sodium chloride solution, and can also be widely applied to high-salinity wastewater treatment to oxidize a large amount of chlorine ions in high-salinity wastewater to produce chlorine gas, as well as hydrogen gas, sodium hydroxide and other high-value-added products.

[0053] (2) The composite chlorine-evolving electrode provided by the present application has an overpotential of 1.41V (vs. RHE) at a current density of 10mA / cm 2 2 The overpotential of a commercial titanium-ruthenium-iridium electrode is 1.46V (vs. RHE) at a current density of 10mA / cm

[0054] (3) The composite chlorine-evolving electrode provided by the present application has excellent electrocatalytic chlorine-evolving stability. In a three-electrode double-chamber H-type electrolytic cell (the composite chlorine-evolving electrode as the working electrode, a platinum sheet electrode as the counter electrode, a saturated calomel electrode as the reference electrode, and 5M pH=2 sodium chloride solution as the electrolyte), the overpotential of the composite chlorine-evolving electrode is 1.41V (vs. RHE) at a current density of 10mA / cm​2 It worked stably for more than 200 hours at a current density of 1.5 wt %. The voltage increased by 2% and the performance decayed slightly, showing excellent electrocatalytic chlorine evolution stability.

[0055] (4) Compared with the high-cost commercial titanium ruthenium iridium electrode, the composite chlorine evolution electrode provided by the present invention has more excellent catalytic performance and stability, and its cost is lower than that of the commercial titanium ruthenium iridium electrode that requires the addition of precious metals, and has broad commercial prospects in the chlor-alkali industry.

[0056] (5) The preparation method of the composite chlorine evolution electrode provided by the present invention is simple, fast, green and efficient, uses low raw material costs, has low manufacturing costs and is suitable for large-scale production, showing the potential for large-scale industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 This is a SEM image of the CoO-Yb2O3 / TF composite chlorine evolution electrode provided in Example 1 of the present invention.

[0058] Figure 2 This is a SEM image of the Yb2O3 / TF chlorine evolution electrode provided in Comparative Example 1 of the present invention.

[0059] Figure 3 The CoO provided in Comparative Example 2 of the present invention x SEM image of / TF chlorine evolution electrode.

[0060] Figure 4 The CoO-Yb2O3 / TF composite chlorine evolution electrode provided in Example 1 of the present invention, the Yb2O3 / TF chlorine evolution electrode provided in Comparative Example 1 and the CoO provided in Comparative Example 2 x XRD comparison diagram of / TF chlorine evolution electrode.

[0061] Figure 5 This is a current density-voltage comparison diagram of the CoO-Yb2O3 / TF composite chlorine evolution electrode provided in Examples 1, 2 and 6 of the present invention.

[0062] Figure 6 The CoO-Yb2O3 / TF composite chlorine evolution electrode provided in Example 1 of the present invention, the Yb2O3 / TF chlorine evolution electrode provided in Comparative Example 1, and the CoO provided in Comparative Example 2 are x / TF chlorine evolution electrode and the current density-voltage comparison diagram of the commercial titanium ruthenium iridium electrode provided in Comparative Example 3.

[0063] Figure 7 This is a stability test diagram of the CoO-Yb2O3 / TF composite chlorine evolution electrode provided in Example 1 of the present invention using the chronopotentiometry method. DETAILED DESCRIPTION

[0064] The technical solutions of the present application are further illustrated below in combination with the drawings and through specific embodiments. However, the following examples are merely simple examples of the present application and do not represent or limit the protection scope of the present application, and the protection scope of the present application is subject to the claims.

[0065] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0066] Example 1

[0067] The present example provides a preparation method of a composite chlorine evolution electrode, which comprises the following steps:

[0068] A cobalt-ytterbium mixed salt solution containing 11 mmol of cobalt nitrate and 11 mmol of ytterbium nitrate is prepared, wherein the total mass concentration of cobalt nitrate and ytterbium nitrate is 11.34 g / L; the foamed titanium is put into a NaOH solution with a concentration of 0.2 g / mL, heated in an oil bath at 80°C for 60 min, then immersed in an oxalic acid solution with a concentration of 0.15 g / mL, and chemically etched at 80°C for 120 min until the solution turns dark brown, and then washed with deionized water after etching to obtain pretreated foamed titanium, which is put into anhydrous ethanol for standby;

[0069] The pretreated foamed titanium is used as an anode, a saturated calomel electrode is used as a reference electrode, and a platinum sheet is used as an auxiliary electrode, the anode is immersed in the cobalt-ytterbium mixed salt solution, and Co(OH)2-Yb(OH)3 / TF electrodes are obtained by electrodeposition at a current density of 20 mA / cm 2 for 40 min at 30°C.

[0070] The Co(OH)2-Yb(OH)3 / TF is calcined at 500°C for 2 h under an argon atmosphere to obtain a CoO-Yb2O3 / TF composite chlorine evolution electrode.

[0071] Example 2

[0072] The present example provides a preparation method of a composite chlorine evolution electrode, which is different from example 1 in that the calcination temperature is 400°C, and the rest of the preparation method and parameters remain the same as in example 1.

[0073] Example 3

[0074] The present example provides a preparation method of a composite chlorine evolution electrode, which is different from example 1 in that the calcination temperature is 550°C, and the rest of the preparation method and parameters remain the same as in example 1.

[0075] Example 4

[0076] The embodiment provides a preparation method of a composite chlorine evolution electrode, and the preparation method comprises the following steps:

[0077] A cobalt-ytterbium mixed salt solution containing 11 mmol of cobalt nitrate and 44 mmol of ytterbium nitrate is prepared, wherein the total mass concentration of the cobalt nitrate and the ytterbium nitrate is 15 g / L; the foamed titanium is put into a NaOH solution with a concentration of 0.2 g / mL, heated in an oil bath at 80 ℃ for 60 min, then immersed into an oxalic acid solution with a concentration of 0.15 g / mL, and chemically etched at 80 ℃ for 120 min until the solution becomes dark brown, and then cleaned with deionized water after etching to obtain pretreated foamed titanium, which is put into anhydrous ethanol for standby;

[0078] The pretreated foamed titanium is used as an anode and immersed in the cobalt-ytterbium mixed salt solution, and then electrodeposited at a current density of 30 mA / cm 2 and 25 ℃ for 30 min to obtain a Co(OH)2-Yb(OH)3 / TF electrode.

[0079] The Co(OH)2-Yb(OH)3 / TF is calcined at 500 ℃ for 1.5 h under an argon atmosphere to obtain a CoO-Yb2O3 / TF composite chlorine evolution electrode.

[0080] Embodiment 5

[0081] The embodiment provides a preparation method of a composite chlorine evolution electrode, and the preparation method comprises the following steps:

[0082] A cobalt-ytterbium mixed salt solution containing 11 mmol of cobalt nitrate and 2.75 mmol of ytterbium nitrate is prepared, wherein the total mass concentration of the cobalt nitrate and the ytterbium nitrate is 10 g / L; the foamed titanium is put into a NaOH solution with a concentration of 0.2 g / mL, heated in an oil bath at 80 ℃ for 60 min, then immersed into an oxalic acid solution with a concentration of 0.15 g / mL, and chemically etched at 80 ℃ for 120 min until the solution becomes dark brown, and then cleaned with deionized water after etching to obtain pretreated foamed titanium, which is put into anhydrous ethanol for standby;

[0083] The pretreated foamed titanium is used as an anode and immersed in the cobalt-ytterbium mixed salt solution, and then electrodeposited at a current density of 25 mA / cm 2 and 35 ℃ for 60 min to obtain a Co(OH)2-Yb(OH)3 / TF electrode.

[0084] The Co(OH)2-Yb(OH)3 / TF is calcined at 500 ℃ for 2.5 h under an argon atmosphere to obtain a CoO-Yb2O3 / TF composite chlorine evolution electrode.

[0085] Embodiment 6

[0086] The embodiment provides a preparation method of a composite chlorine evolution electrode, which is different from the preparation method in Embodiment 1 in that the calcination temperature is 600 DEG C, and the rest of the preparation method and parameters are consistent with those in Embodiment 1.

[0087] Embodiment 7

[0088] The embodiment provides a preparation method of a composite chlorine evolution electrode, which is different from the preparation method in Embodiment 1 in that the calcination temperature is 350 DEG C, and the rest of the preparation method and parameters are consistent with those in Embodiment 1.

[0089] Embodiment 8

[0090] The embodiment provides a preparation method of a composite chlorine evolution electrode, which is different from the preparation method in Embodiment 1 in that a cobalt-ytterbium mixed salt solution containing 11 mmol of cobalt nitrate and 55 mmol of ytterbium nitrate is prepared, and the rest of the preparation method and parameters are consistent with those in Embodiment 1.

[0091] Embodiment 9

[0092] The embodiment provides a preparation method of a composite chlorine evolution electrode, which is different from the preparation method in Embodiment 1 in that the electrodeposition time is 70 min, and the rest of the preparation method and parameters are consistent with those in Embodiment 1.

[0093] Embodiment 10

[0094] The embodiment provides a preparation method of a composite chlorine evolution electrode, which is different from the preparation method in Embodiment 1 in that the calcination is carried out in an air atmosphere to obtain a Co3O4-Yb2O3 / TF composite chlorine evolution electrode, and the rest of the preparation method and parameters are consistent with those in Embodiment 1.

[0095] Comparative Example 1

[0096] The comparative example provides a preparation method of a chlorine evolution electrode, which is different from the preparation method in Embodiment 1 in that a ytterbium salt solution containing 22 mmol of ytterbium nitrate is prepared, the mass concentration of the ytterbium nitrate is 11.34 g / L, a Yb2O3 / TF composite chlorine evolution electrode is obtained, and the rest of the preparation method and parameters are consistent with those in Embodiment 1.

[0097] Comparative Example 2

[0098] The comparative example provides a preparation method of a chlorine evolution electrode, which is different from the preparation method in Embodiment 1 in that a cobalt salt solution containing 22 mmol of cobalt nitrate is prepared, the mass concentration of the cobalt nitrate is 11.34 g / L, a CoO x / TF composite chlorine evolution electrode is obtained, and the rest of the preparation method and parameters are consistent with those in Embodiment 1.

[0099] Comparative Example 3

[0100] The present comparative example provides a commercially available commercial titanium-ruthenium-iridium electrode (purchased from Suzhou Shulai Industrial Technology Co., Ltd.).

[0101] Figure 1 The SEM image of the CoO-Yb2O3 / TF composite chlorine evolution electrode provided by the present application Example 1 is shown, Figure 2 The SEM image of the Yb2O3 / TF chlorine evolution electrode provided by the present application Comparative Example 1 is shown, Figure 3 The SEM image of the CoO x / TF chlorine evolution electrode provided by the present application Comparative Example 2 is shown. As can be seen from the figure, CoO and Yb2O3 are uniformly loaded inside and on the surface of the titanium foam substrate, and compared with the Yb2O3 / TF chlorine evolution electrode and the CoO x / TF chlorine evolution electrode, the surface has uniform fine pores, which is conducive to adsorbing free chloride ions and desorbing generated bubbles during the chlorine evolution process.

[0102] Figure 4 The XRD comparison chart of the CoO-Yb2O3 / TF composite chlorine evolution electrode provided by the present application Example 1, the Yb2O3 / TF chlorine evolution electrode provided by the present application Comparative Example 1, and the CoO x / TF chlorine evolution electrode provided by the present application Comparative Example 2 is shown. As can be seen from the figure, in the composite chlorine evolution electrode in Example 1, the active material contains CoO and Yb2O3.

[0103] At room temperature, the chlorine evolution reaction (CER) performance test of the electrode was carried out in a standard three-electrode system in an H-type electrolytic cell. Nafion-211 proton exchange membrane was used to separate the cathode chamber and the anode chamber, and a conical flask containing NaOH solution was connected to the gas outlet of the anode chamber for absorbing the generated Cl2.

[0104] The composite chlorine evolution electrodes provided by Examples 1-10, the chlorine evolution electrodes provided by Comparative Examples 1-2, and the commercially available commercial titanium anode provided by Comparative Example 3 were used as working electrodes, and the area of the electrodes immersed in the electrolyte was controlled to be 1 cm 2 , a saturated calomel electrode (SCE) was used as a reference electrode, a platinum sheet was used as a counter electrode, a 5M NaCl solution (pH=2) was used to simulate the acidic environment of the chlor-alkali industry, and linear sweep (LSV) test (scanning speed was 5mV / s) was carried out by an electrochemical workstation (Shanghai Chenhua CHI760E), and constant potential method (CP) was used for stability test (current density was controlled at 10mA / cm 2 ). The specific test results are shown in Table 1.

[0105] Figure 5The current density-voltage contrast chart of the CoO-Yb2O3 / TF composite chlorine evolution electrode provided by the embodiment 1, the embodiment 2 and the embodiment 6 of the present application is shown, and it can be seen from the chart that the catalytic chlorine evolution activity is closely related to the calcination temperature, and has certain catalytic chlorine evolution activity when calcined at 400 DEG C-550 DEG C, and the catalytic chlorine evolution activity is best when calcined at 500 DEG C, and the overpotential is obviously increased when the calcination temperature is too high.

[0106] Figure 6 The current density-voltage contrast chart of the CoO-Yb2O3 / TF composite chlorine evolution electrode provided by the embodiment 1 of the present application, the Yb2O3 / TF chlorine evolution electrode provided by the comparative example 1, the CoO x / TF chlorine evolution electrode provided by the comparative example 2 and the commercially available commercial titanium ruthenium iridium electrode provided by the comparative example 3 is shown, and it can be seen from the chart that the CoO-Yb2O3 / TF composite chlorine evolution electrode provided by the embodiment 1 of the present application is 1.41V (vs. RHE) when the current density is 10mA / cm 2 , the commercial titanium ruthenium iridium electrode is 1.46V (vs. RHE) when the current density is 10mA / cm 2 , compared with the above, the overpotential of the embodiment 1 is reduced by 50mV, which indicates that the electrocatalytic chlorine evolution performance of the composite chlorine evolution electrode provided by the embodiment 1 of the present application is more excellent, and has higher chlorine evolution activity, while the Yb2O3 / TF chlorine evolution electrode provided by the comparative example 1 and the CoO x / TF chlorine evolution electrode provided by the comparative example 2 basically have no catalytic effect, and further indicate that the Yb element and the Co element produce a synergistic catalytic chlorine evolution effect.

[0107] Figure 7 The stability test chart of the chronopotentiometry method of the CoO-Yb2O3 / TF composite chlorine evolution electrode provided by the embodiment 1 of the present application is shown, and it can be seen from the chart that the potential of the CoO-Yb2O3 / TF composite chlorine evolution electrode is increased by 0.16V after 260h of chlorine evolution reaction, and the electrode performance does not obviously decrease, and still has very high catalytic activity, and further indicate that the CoO-Yb2O3 / TF composite chlorine evolution electrode provided by the embodiment 1 of the present application has excellent stability, and has wide application scenarios and potential in the chlor-alkali industry field.

[0108] Table 1

[0109] Note: " / " indicates that the electrode does not contain Co element or Yb element.

[0110] It can be seen from the test results that:

[0111] (1) From Example 1 to Example 5, it can be seen that the composite chlorine evolution electrode provided by the present application contains Co element and Yb element in the active material, the introduction of Yb element can produce a synergistic effect with Co element, adjust the charge distribution around Co element and improve the conductivity of the composite chlorine evolution electrode, the adjustment of charge distribution and the improvement of conductivity jointly optimize the chlorine evolution reaction mechanism, enhance the catalytic chlorine evolution activity, and the overpotential is 50mV-89mV, which is lower than the overpotential of 100mV of the commercial titanium ruthenium iridium electrode in Example 3 at 10mA / cm 2 , that is, the electrocatalytic chlorine evolution performance of the CoO-Yb2O3 / TF composite chlorine evolution electrode of the present application is more excellent. 2

[0112] (2) From Example 1 and Example 6-7, it can be seen that by further adjusting the calcination temperature to 400-550℃, the crystal structure of the active material in the obtained CoO-Yb2O3 / TF composite chlorine evolution electrode is complete, and has more catalytically active sites, and the chlorine evolution activity is more excellent.

[0113] (3) From Example 1 and Example 8, it can be seen that by further adjusting the molar ratio of cobalt salt and ytterbium salt to 1:(0.25-4), the obtained CoO-Yb2O3 / TF composite chlorine evolution electrode can achieve the best catalytic effect.

[0114] (4) From Example 1 and Example 9, it can be seen that by further adjusting the electrodeposition time to 30-60min, the content of Co element and Yb element in the active material in the CoO-Yb2O3 / TF composite chlorine evolution electrode can be adjusted, so that the catalytic performance of the composite chlorine evolution electrode is more excellent, and the chlorine evolution activity is more excellent.

[0115] (5) From Example 1 and Example 10, it can be seen that the further calcination is carried out in an inert atmosphere, which avoids the generation of other impurity phases such as cobalt trioxide in the active material in the CoO-Yb2O3 / TF composite chlorine evolution electrode, and the spinel structure of cobalt trioxide will limit the exposure of active sites, and thus affect the chlorine evolution activity.

[0116] (6) From Example 1 and Comparative Examples 1-2, it can be seen that the composite chlorine evolution electrode provided by the present application contains Co element and Yb element in the active material, the introduction of Yb element can produce a synergistic effect with Co element, adjust the charge distribution around Co element and improve the conductivity of the composite chlorine evolution electrode, the adjustment of charge distribution and the improvement of conductivity jointly optimize the chlorine evolution reaction mechanism, enhance the catalytic chlorine evolution activity; when Yb2O3 / TF chlorine evolution electrode is prepared only by using Yb element or CoO x ​The chlorine evolution electrode has no catalysis basically.

[0117] In summary, the composite chlorine evolution electrode provided by the application contains Co elements and Yb elements in the active material, the introduction of Yb elements can produce a synergistic effect with Co elements, adjust the charge distribution around Co elements and improve the conductivity of the composite chlorine evolution electrode, the adjustment of the charge distribution and the improvement of the conductivity jointly optimize the chlorine evolution reaction mechanism and enhance the catalytic chlorine evolution activity; and the preparation method is simple, fast, green, efficient, low in raw material cost and manufacturing cost, suitable for large-scale production and showing the potential for industrial large-scale application.

[0118] The applicant declares that the above is only a specific embodiment of the application, but the protection scope of the application is not limited thereto, and those skilled in the art should understand that any changes or replacements within the technical scope disclosed by the application, which can be easily thought of by any person skilled in the art, falls within the protection scope and disclosure scope of the application.

Claims

1. A method for preparing a composite chlorine evolution electrode, characterized in that: The preparation method comprises the following steps: A titanium-based material is used as a carrier and placed on an anode, and is electro-deposited in a cobalt-ytterbium mixed salt solution. After calcination, a composite chlorine evolution electrode is obtained.

2. The preparation method according to claim 1, characterized in that In the cobalt-ytterbium mixed salt solution, the molar ratio of cobalt salt to ytterbium salt is 1:(0.25-4); Preferably, the total mass concentration of cobalt salt and ytterbium salt in the cobalt-ytterbium mixed salt solution is 10 g / L to 15 g / L.

3. The preparation method according to claim 2, characterized in that The titanium-based material includes pre-treated titanium foam; Preferably, the preparation step of the pretreated titanium foam comprises: alkali washing the titanium foam, then immersing it in an acid solution for pickling and etching, and obtaining the pretreated titanium foam after washing; Preferably, the cobalt salt comprises any one of cobalt nitrate, cobalt chloride, cobalt sulfate or cobalt acetate, or a combination of at least two thereof, preferably cobalt chloride and / or cobalt nitrate; Preferably, the ytterbium salt includes any one of ytterbium nitrate, ytterbium chloride, ytterbium sulfate or ytterbium acetate, or a combination of at least two thereof, preferably ytterbium chloride and / or ytterbium nitrate.

4. The preparation method according to any one of claims 1 to 3, characterized in that The calcination temperature is 400°C to 550°C; Preferably, the calcination time is 1.5 h to 2.5 h.

5. The preparation method according to any one of claims 1 to 4, characterized in that The calcination is carried out under an inert atmosphere; Preferably, the gas used in the inert atmosphere includes argon.

6. The preparation method according to any one of claims 1 to 5, characterized in that The current density of the electrodeposition was 20 mA / cm 2 ~30mA / cm 2 ; Preferably, the temperature of the electrodeposition is 25°C to 35°C; Preferably, the electrodeposition time is 30 min to 60 min.

7. A composite chlorine evolution electrode, characterized in that: The composite chlorine evolution electrode is prepared according to the preparation method according to any one of claims 1-6.

8. The composite chlorine evolution electrode according to claim 7, characterized in that: The composite chlorine evolution electrode comprises a titanium-based material, and the surface and interior of the titanium-based material are loaded with Co-containing oxides and Yb-containing oxides; Preferably, the Co-containing oxide comprises CoO; Preferably, the Yb-containing oxide includes Yb2O3.

9. The composite chlorine evolution electrode according to claim 8, characterized in that: The Co element accounts for 10wt% to 15wt% of the total mass of the composite chlorine evolution electrode; Preferably, the Yb element accounts for 5wt% to 45wt% of the total mass of the composite chlorine evolution electrode.

10. An application of a composite chlorine evolution electrode, characterized in that: The composite chlorine evolution electrode prepared by the preparation method according to any one of claims 1 to 6, or the composite chlorine evolution electrode according to any one of claims 7 to 9, is used to treat chloride ions in chlorine-containing wastewater and / or electrolyze brine to produce chlorine.

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