阅读说明：本技术 一种三氧化二铁/氧化亚铜/碳布析氧电催化薄膜的制备方法 (Preparation method of ferric oxide/cuprous oxide/carbon cloth oxygen evolution electro-catalytic film ) 是由 徐晨 张晴 马萱航 杨琪 赵旭宁 张娜 房永征 刘玉峰 于 2021-06-02 设计创作，主要内容包括：本发明公开了一种三氧化二铁/氧化亚铜/碳布析氧电催化薄膜的制备方法。本发明的制备方法包括：1.将碳布基体进行亲水性预处理,备用；2.将步骤1所得基体浸没于Fe～(3+)前驱体溶液中,进行水热反应得FeOOH薄膜,然后在500℃下恒温煅烧得到Fe-2O-3薄膜；3.以Cu～(2+)的前驱体溶液做电解液,以步骤2所得的Fe-2O-3/CC作为阴极,进行恒电压电沉积,制得Fe-2O-3/Cu-2O/CC电催化薄膜,制备所得的电催化薄膜的析氧过电位最低可达296mv,塔菲尔斜率最低为66mv/dec。本发明的制备工艺简单,重复性高,制备所得的电催化薄膜具有优异的电催化析氧性能和稳定性。(The invention discloses a preparation method of an iron trioxide/cuprous oxide/carbon cloth oxygen electrocatalytic film. The preparation method comprises the following steps: 1. carrying out hydrophilic pretreatment on the carbon cloth substrate for later use; 2. immersing the substrate obtained in the step 1 in Fe 3+ In the precursor solution, carrying out hydrothermal reaction to obtain FeOOH film, and then calcining at constant temperature of 500 ℃ to obtain Fe 2 O 3 A film; 3. with Cu 2+ Using the precursor solution as electrolyte, and using the Fe obtained in the step 2 2 O 3 the/CC is taken as a cathode to carry out constant voltage electrodeposition to prepare Fe 2 O 3 /Cu 2 O/CC electrocatalytic film, the oxygen evolution overpotential of the electrocatalytic film prepared thereby being the lowestCan reach 296mv, and the lowest gradient of the Tafel is 66 mv/dec. The preparation process is simple, the repeatability is high, and the prepared electro-catalytic film has excellent electro-catalytic oxygen evolution performance and stability.)

1. Fe₂O₃/Cu₂The preparation method of the O/CC electrocatalytic film is characterized by comprising the following steps:

step 1: putting the carbon cloth substrate into a nitric acid aqueous solution, carrying out hydrophilic treatment through autoclave reaction, washing and drying for later use;

step 2: immersing the carbon cloth substrate treated in the step 1 in Fe³⁺Carrying out hydrothermal reaction in the precursor solution, washing and drying after the reaction to obtain a precursor FeOOH/CC;

and step 3: calcining the precursor obtained in the step 2 to obtain Fe₂O₃/CC。

And 4, step 4: with Cu²⁺Using the precursor solution as electrolyte, and using the Fe obtained in step 3₂O₃taking/CC as a cathode, Ag/AgCl as a reference electrode, taking a platinum sheet as a counter electrode to perform constant-voltage electrodeposition, washing with water and drying to obtain Fe₂O₃/Cu₂O/CC electrocatalytic film.

2. Fe as claimed in claim 1₂O₃/Cu₂The preparation method of the O/CC electrocatalytic film is characterized in that the molar concentration of the nitric acid aqueous solution in the step 1 is 4M, the reaction temperature is 100 ℃, and the reaction time is 4 hours.

3. Fe as claimed in claim 1₂O₃/Cu₂The preparation method of the O/CC electrocatalytic film is characterized in that Fe in the step 2³⁺The precursor solution is an acidic aqueous solution of ferric salt and sodium nitrate, and the molar concentration of the sodium nitrate is 0.8-1.0M; the molar concentration ratio of the ferric salt to the sodium nitrate is 1: 8 to 10.

4. Fe as claimed in claim 1₂O₃/Cu₂The preparation method of the O/CC electrocatalytic film is characterized in that the temperature of the hydrothermal reaction in the step 2 is 100-150 ℃ and the time is 6-12 h.

5. Fe as claimed in claim 3₂O₃/Cu₂The preparation method of the O/CC electrocatalytic film is characterized in that the ferric salt is at least one of ferric sulfate, ferric nitrate, ferric chloride and corresponding hydrates thereof.

6. Fe as claimed in claim 3₂O₃/Cu₂The preparation method of the O/CC electrocatalytic film is characterized in that the acidic aqueous solution is obtained by dissolving ferric salt and sodium nitrate in water and then adjusting the pH value to 1.5-2 by 1-2M hydrochloric acid solution.

7. Fe as claimed in claim 1₂O₃/Cu₂The preparation method of the O/CC electrocatalytic film is characterized in that in the step 3The calcining temperature is 500 ℃, and the time is 2-5 h.

8. Fe as claimed in claim 1₂O₃/Cu₂The preparation method of the O/CC electrocatalytic film is characterized in that Cu in the step 4²⁺The precursor solution is an alkaline aqueous solution of copper sulfate and lactic acid, wherein the molar concentration of the copper sulfate is 0.1-0.2M, and the molar ratio of the copper sulfate to the lactic acid is 0.1: 3.

9. Fe of claim 8₂O₃/Cu₂The preparation method of the O/CC electrocatalytic film is characterized in that the alkaline aqueous solution is obtained by dissolving copper sulfate and lactic acid in water and then adjusting the pH value to 10-12 through 3-5M NaOH solution.

10. Fe as claimed in claim 1₂O₃/Cu₂The preparation method of the O/CC electrocatalytic film is characterized in that the process parameters of the constant-voltage electrodeposition in the step 4 are as follows: the electrodeposition temperature is 35 ℃, the working voltage is-0.5 to-0.7V, and the deposition time is 300 to 700 s.

Technical Field

The invention relates to a preparation method of an iron trioxide/cuprous oxide/carbon cloth oxygen electrocatalytic film, belonging to the technical field of electrocatalytic materials.

Background

Greenhouse effect and energy shortage are two major problems facing the human society nowadays, and the search for high-efficiency harmless environment-friendly pollution treatment technology becomes a problem to be solved by human beings urgently. Hydrogen energy is widely used as an energy carrier due to its high energy density, splitting water is considered one of the most promising strategies for producing clean and renewable fuels, and water oxidation half-reaction (OER) is critical for the overall water splitting process due to its slow kinetics, which can lead to excessive potentials and reduce power conversion efficiency. Therefore, designing an efficient OER catalyst can improve reaction kinetics and reduce overpotential. Hitherto, containing noble metals such as RuO₂And IrO₂The catalyst has great catalytic activity for water oxidation. However, the high cost and scarcity of noble metals limits their practical and large-scale applications. Therefore, the development of efficient and low-cost OER electrocatalyst has become an important direction of research in this field at present.

Iron oxide, as an important oxide in new nano-materials, shows excellent chemical stability, corrosion resistance, high abundance in earth crust, nontoxicity, low processing cost and biodegradability in a wide pH range, resulting in high economic feasibility, and there are few reports in the literature that pure hematite is used as an OER electrocatalyst because of Fe₂O₃The slow kinetics and poor conductivity limit OER efficiency. By the pair of Fe₂O₃The catalyst is doped or compositely modified to obtainHigh Fe₂O₃The catalytic activity of (3).

In recent years, the use of copper-based materials as potential OER catalysts has received widespread attention due to the high purity and low cost of copper and the simplicity of these systems. Du (X.Liu, Z.Sun, S.Cui, P.Du, Cu oxide in film direct attached from a single chip salt connected with a conductive electrode for an electric oxygen reaction, electric. acta 187(2016) 381-388.) team reports that Cu oxide in film is added with Cu₂The O film has good catalytic activity and stability to OER, which shows that Cu₂O is a promising OER catalyst with an oxygen evolution overpotential of at least 296mv and a column-Fei slope of 66 mv/dec.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: high cost and scarcity of noble metals and Fe in OER catalysts₂O₃Insufficient kinetics and conductivity, etc.

In order to solve the technical problem, the invention provides Fe₂O₃/Cu₂The preparation method of the O/CC electrocatalytic film comprises the following steps:

step 1: putting the carbon cloth substrate into a nitric acid aqueous solution, carrying out hydrophilic treatment through autoclave reaction, washing and drying for later use;

step 2: immersing the carbon cloth substrate treated in the step 1 in Fe³⁺Carrying out hydrothermal reaction in the precursor solution, washing and drying after the reaction to obtain a precursor FeOOH/CC;

and step 3: calcining the precursor obtained in the step 2 to obtain Fe₂O₃/CC。

And 4, step 4: with Cu²⁺Using the precursor solution as electrolyte, and using the Fe obtained in step 3₂O₃taking/CC as a cathode, Ag/AgCl as a reference electrode, taking a platinum sheet as a counter electrode to perform constant-voltage electrodeposition, washing with water and drying to obtain Fe₂O₃/Cu₂O/CC electrocatalytic film.

Preferably, the molar concentration of the nitric acid aqueous solution in the step 1 is 4M, the temperature of the reaction is 100 ℃, and the time is 4 h.

Preferably, Fe in said step 2³⁺The precursor solution is an acidic aqueous solution of ferric salt and sodium nitrate, and the molar concentration of the sodium nitrate is 0.8-1.0M; the molar concentration ratio of the ferric salt to the sodium nitrate is 1: 8 to 10.

Preferably, the temperature of the hydrothermal reaction in the step 2 is 100-150 ℃ and the time is 6-12 h.

More preferably, the iron salt is at least one of ferric sulfate, ferric nitrate, ferric chloride and their corresponding hydrates.

Preferably, the acidic aqueous solution is obtained by dissolving ferric salt and sodium nitrate in water and then adjusting the pH value to 1.5-2 by 1-3M hydrochloric acid solution.

Preferably, the calcining temperature in the step 3 is 500 ℃ and the calcining time is 2-5 h.

Preferably, Cu in said step 4²⁺The precursor solution is an alkaline aqueous solution of copper sulfate and lactic acid, wherein the molar concentration of the copper sulfate is 0.1-0.2M, and the molar ratio of the copper sulfate to the lactic acid is 0.1: 3.

Preferably, the alkaline aqueous solution is obtained by dissolving copper sulfate and lactic acid in water and then adjusting the pH value to 10-12 through a 3-5M NaOH solution.

Preferably, the process parameters of the constant voltage electrodeposition in the step 4 are as follows: the electrodeposition temperature is 35 ℃, the working voltage is-0.5 to-0.7V, and the deposition time is 300 to 700 s.

Compared with the prior art, the invention has the beneficial effects that:

1. the invention utilizes the hydrothermal method and the electrodeposition method to prepare Fe₂O₃/Cu₂The O/CC electrocatalytic film has uniform surface, good stability of active substances, difficult peeling, easy control of film area and Fe₂O₃The morphology of the array can provide enough space and a large number of active centers for mass transfer; the core-shell heterostructure is Fe by electronic interaction₂O₃And Cu₂The electronic structure modulation of O provides a larger contact area, thereby realizing effective electron transfer and reducing the overpotential of the reaction;

2. hair brushMing Fe₂O₃/Cu₂The O/CC electro-catalysis film can be recycled, so that the cost is greatly reduced, the secondary pollution is reduced, and the problem that the powder catalyst is difficult to recover is solved;

3. the preparation process is simple, high in repeatability and low in economic cost; fe with different cuprous oxide contents is prepared by regulating and controlling parameters such as electrodeposition time, temperature and the like₂O₃/Cu₂O/CC electrocatalytic film at 10mA cm^-2A low overpotential of 66mv/dec was exhibited.

Drawings

FIG. 1 shows Fe obtained in examples 1 to 3₂O₃/Cu₂O/CC electrocatalytic films (CFC-3, CFC-5 and CFC-7 respectively) and the CC film obtained in step 1 and the Fe obtained in step 2 in example 1₂O₃XRD contrast of/CC (FC) film and FeOOH/CC (FeOOH);

FIG. 2 shows Fe obtained in step (2) of example 1₂O₃SEM image of/CC film surface;

FIG. 3 is Fe prepared in example 1₂O₃/Cu₂SEM picture of the surface of the O/CC electrocatalytic film;

FIG. 4 shows Fe obtained in examples 1 to 3₂O₃/Cu₂O/CC electrocatalytic films (CFC-3, CFC-5 and CFC-7 respectively) and the CC film obtained in step 1 and the Fe obtained in step 2 in example 1₂O₃OER polarization plot for the/CC (FC) film.

Detailed Description

In order to make the invention more comprehensible, preferred embodiments are described in detail below with reference to the accompanying drawings.

Example 1

Fe₂O₃/Cu₂The preparation method of the O/CC electrocatalytic film comprises the following steps:

(1) and (3) placing the carbon cloth substrate in 4M nitric acid aqueous solution, reacting for 4 hours at 100 ℃ to perform hydrophilic treatment, washing with deionized water to be neutral after the reaction is finished, and drying for later use.

(2) Mixing ferric chloride hexahydrate (FeCl)₃·6H₂O) and sodium nitrate are dissolved in water to prepare Fe with the concentration of ferric chloride hexahydrate of 0.1M and the concentration of sodium nitrate of 0.8M³⁺The pH of the precursor solution of (1) was adjusted to 1.9 with 2M hydrochloric acid. Immersing the carbon cloth substrate in Fe³⁺Placing the precursor solution in a high-pressure reaction kettle to perform hydrothermal film-forming reaction at 120 ℃ for 6 hours, washing with deionized water after the reaction is finished, drying to obtain a FeOOH/CC precursor, placing the precursor in a muffle furnace, and calcining at the constant temperature of 500 ℃ for 2 hours to obtain Fe₂O₃a/CC film.

(3) 100mL of a 3M lactic acid solution containing 0.1M copper sulfate was prepared, and 30mL of the solution was adjusted to pH 10 with 4M sodium hydroxide solution to obtain Cu²⁺The precursor solution of (1). With Cu²⁺The precursor solution is used as electrolyte, and electrodeposition is carried out by using an autolab electrochemical workstation and adopting a three-electrode system, namely Fe obtained in the step (2)₂O₃And performing electrodeposition by taking the/CC film as a cathode, a platinum wire as a counter electrode and an Ag/AgCl electrode as a reference electrode, wherein the electrodeposition temperature is 35 ℃, the working voltage is-0.5V, and the deposition time is 300 s. After the reaction is finished, washing with deionized water, and drying at room temperature to prepare Fe₂O₃/Cu₂O/CC electrocatalytic film.

(4) Performing electrochemical performance test on the product obtained in the step (3), using an Autolab electrochemical workstation in a KOH solution of 1M, adopting a three-electrode system to perform electrochemical performance test on the product obtained in the step (3), wherein Hg/HgO is used as a reference electrode, a foil is used as a counter electrode, and the scanning speed is 5mv s^-1. The overpotential is 302mv, the gradient of Taffel is 207mv dec^-1。

Example 2

Fe₂O₃/Cu₂The preparation method of the O/CC electrocatalytic film comprises the following steps:

(1) and (3) placing the carbon cloth substrate in 4M nitric acid aqueous solution, reacting for 4 hours at 100 ℃ to perform hydrophilic treatment, washing with deionized water to be neutral after the reaction is finished, and drying for later use.

(2) Mixing ferric chloride hexahydrate (FeCl)₃·6H₂O) and sodium nitrate are dissolved in waterFe with a concentration of 0.1M ferric chloride hexahydrate and a concentration of 0.9M sodium nitrate³⁺The pH of the precursor solution of (1) was adjusted to 1.9 with 2M hydrochloric acid. Immersing the carbon cloth substrate in Fe³⁺Placing the precursor solution in a high-pressure reaction kettle to perform hydrothermal film-forming reaction at the reaction temperature of 100 ℃ for 12 hours, washing the precursor solution with deionized water after the reaction is finished, drying the precursor solution to obtain a FeOOH/CC precursor, placing the precursor in a muffle furnace, and calcining the precursor at the constant temperature of 500 ℃ for 2 hours to obtain Fe₂O₃a/CC film.

(3) 100mL of a 3M lactic acid solution containing 0.1M copper sulfate was prepared, and 30mL of the solution was adjusted to pH 10 with 4M sodium hydroxide solution to obtain Cu²⁺The precursor solution of (1). With Cu²⁺The precursor solution is used as electrolyte, and electrodeposition is carried out by using an autolab electrochemical workstation and adopting a three-electrode system, namely Fe obtained in the step (2)₂O₃And performing electrodeposition by taking the/CC film as a cathode, a platinum wire as a counter electrode and an Ag/AgCl electrode as a reference electrode, wherein the electrodeposition temperature is 35 ℃, the working voltage is-0.5V, and the deposition time is 500 s. After the reaction is finished, washing with deionized water, and drying at room temperature to obtain Fe₂O₃/Cu₂O/CC electrocatalytic film.

(4) Performing electrochemical performance test on the product obtained in the step (3), using an Autolab electrochemical workstation in a KOH solution of 1M, adopting a three-electrode system to perform electrochemical performance test on the product obtained in the step (3), wherein Hg/HgO is used as a reference electrode, a foil is used as a counter electrode, and the scanning speed is 5mv s^-1. The over-potential is 296mv, the gradient of Taffel is 66mv dec^-1。

Example 3

Fe₂O₃/Cu₂The preparation method of the O/CC electrocatalytic film comprises the following steps:

(1) and (3) placing the carbon cloth substrate in 4M nitric acid aqueous solution, reacting for 4 hours at 100 ℃ to perform hydrophilic treatment, washing with deionized water to be neutral after the reaction is finished, and drying for later use.

(2) Mixing ferric chloride hexahydrate (FeCl)₃·6H₂O), sodium nitrate was dissolved in water to prepare ferric chloride hexahydrate at a concentration of 0.1M, 1M concentration of sodium nitrate Fe³⁺The pH of the precursor solution of (1) was adjusted to 1.9 with 2M hydrochloric acid. Immersing the carbon cloth substrate in Fe^{3 +}The precursor solution is placed in a high-pressure reaction kettle to carry out hydrothermal film-forming reaction at the reaction temperature of 120 ℃ for 6 hours, the FeOOH/CC precursor is obtained after the reaction is finished and is washed by deionized water and dried, the precursor is placed in a muffle furnace and is calcined for 2 hours at the constant temperature of 500 ℃ to obtain Fe₂O₃a/CC film.

(3) 100mL of a 3M lactic acid solution containing 0.1M copper sulfate was prepared, and 30mL of the solution was adjusted to pH 10 with 4M sodium hydroxide solution to obtain Cu²⁺The precursor solution of (1). With Cu²⁺The precursor solution is used as electrolyte, and electrodeposition is carried out by using an autolab electrochemical workstation and adopting a three-electrode system, namely Fe obtained in the step (2)₂O₃And performing electrodeposition by taking the/CC film as a cathode, a platinum wire as a counter electrode and an Ag/AgCl electrode as a reference electrode, wherein the electrodeposition temperature is 35 ℃, the working voltage is-0.5V, and the deposition time is 700 s. After the reaction is finished, washing with deionized water, and drying at room temperature to prepare Fe₂O₃/Cu₂O/CC electrocatalytic film.

(4) Performing electrochemical performance test on the product obtained in the step (3), using an Autolab electrochemical workstation in a KOH solution of 1M, adopting a three-electrode system to perform electrochemical performance test on the product obtained in the step (3), wherein Hg/HgO is used as a reference electrode, a foil is used as a counter electrode, and the scanning speed is 5mv s^-1. The overpotential is 343mv, the Taffel slope is 155mv dec^-1。

Wherein, examples 1 to 3 were conducted to obtain Fe₂O₃/Cu₂O/CC electrocatalytic film, CC film obtained in step 1 of example 1, and Fe obtained in step 2₂O₃The XRD contrast of the/CC (FC) thin film and FeOOH/CC (FeOOH) precursor is shown in FIG. 1, and it can be seen from FIG. 1 that Fe obtained in examples 1-3₂O₃/Cu₂The XRD curve of the O/CC electro-catalytic film contains the characteristic diffraction peaks of alpha-ferric oxide crystal and cuprous oxide crystal, which indicates that Fe is successfully synthesized₂O₃/Cu₂O/CC electrocatalytic filmA membrane material; fe obtained in step 2 of example 1₂O₃Film of/CC (FC) and Fe finally obtained₂O₃/Cu₂The scanning electron micrographs of the O/CC electrocatalytic film are shown in FIG. 2 and FIG. 3, respectively, and it can be seen from FIG. 2 and FIG. 3 that Fe₂O₃The crystals are uniformly distributed in an array form and are subjected to electrochemical deposition to obtain Fe₂O₃Uniform deposition of Cu on the surface of CC film₂O nanoparticles; examples 1 to 3 Fe₂O₃/Cu₂O/CC electrocatalytic film, CC film obtained in step 1 of example 1, and Fe obtained in step 2₂O₃The OER polarization curve of the/CC (FC) film is shown in FIG. 4. from FIG. 4, it can be seen that the deposition time is 500s, the electro-catalytic film material reaches 10mA cm^-1The minimum overpotential required is 296mv, and the deposition time is 300s and 700s, respectively, 302mv and 343mv are required to reach 10mA cm^-1。

The above-described embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention in any way and substantially, it should be noted that those skilled in the art may make several modifications and additions without departing from the scope of the present invention, which should also be construed as a protection scope of the present invention.