Transition metal element doped lead dioxide electrolyzed water catalyst as well as preparation method and application thereof

Abstract

The invention discloses a transition metal element doped lead dioxide electrolyzed water catalyst and a preparation method and application thereof, the transition metal element doped lead dioxide electrolyzed water catalyst is composed of lead, oxygen and transition metal elements, and the transition metal elements are one or more of manganese, iron, cobalt and nickel. The transition metal element doped lead dioxide electrode is synthesized through an anodic oxidation deposition method, and lead dioxide serves as a base material, has good conductivity and has good stability in an acid solution; the doped transition metal element is used as an active element of an oxygen evolution reaction, so that the catalytic activity of the catalyst in the oxygen evolution reaction in an acid solution is improved; according to the invention, high stability and activity of the acidic oxygen evolution catalyst are realized, and the manufacturing cost of the proton exchange membrane anode material is reduced; the manufacturing process is simple and easy to implement and has the potential of large-scale production. In conclusion, the method has high economic benefits and application value.

Description

Technical Field

[0001] The invention belongs to the technical field of electrochemical catalysis, and specifically relates to a transition metal element-doped lead dioxide water electrolysis catalyst and a preparation method and application thereof. Background Art

[0002] Proton exchange membrane water electrolysis has excellent performance, with the characteristics of high current density, low ohmic loss, high gas purity, and strong flexibility. It is a water electrolysis hydrogen production technology that is currently developing at a very fast speed. In the proton exchange membrane water electrolysis technology, the reaction occurring at the anode is the oxygen evolution reaction (OER) of four-electron transfer, which has slow kinetics. Therefore, the anode catalyst must have a high electrocatalytic activity to improve the kinetics of OER; when the anode is electrolyzed, a high oxidation potential is applied and the local environment is acidic. The anode catalyst is easily corroded in this environment, so the anode catalyst also needs to have excellent stability in this working environment. At present, the common anode catalyst materials are mainly iridium dioxide (IrO2) and ruthenium dioxide (RuO2) materials, but these materials are based on precious metal elements, with huge costs, which are obstacles to the further application of proton exchange membrane water electrolysis hydrogen production technology. In summary, it is necessary to develop a catalyst based on non-precious metal elements that is both active and stable, and the preparation process should be simple and easy. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a transition metal element doped lead dioxide water electrolysis catalyst and its preparation method and application, so as to solve the problem of high cost of existing anode catalysts, achieve good OER catalytic activity and stability while having a simple and easy preparation process, and greatly reduce the cost of anode materials in proton exchange membrane water electrolysis technology.

[0004] According to the technical solution of the present invention, the present invention provides a transition metal element doped lead dioxide water electrolysis catalyst, the element composition of which is lead, oxygen and transition metal elements, wherein the transition metal element is one or more of manganese, iron, cobalt and nickel.

[0005] According to some embodiments, it is CoMn-PbO x .

[0006] Furthermore, it exhibits high activity in catalyzing oxygen evolution reaction under acidic conditions, with a peak of 10 mA cm -2 The overpotential is 490 mV.

[0007] Furthermore, it exhibits high stability in catalyzing the oxygen evolution reaction under acidic conditions, with a -2 The catalytic activity can be stable for 20 h.

[0008] According to the technical solution of the present invention, the present invention also provides a method for preparing a transition metal element-doped lead dioxide water electrolysis catalyst, which is used to prepare the transition metal element-doped lead dioxide water electrolysis catalyst of the present invention, and comprises the following steps: Step S1, adding a lead salt precursor and a transition metal salt precursor to a nitric acid solution, obtaining a uniform solution after ultrasonic treatment, and using the solution as an electrolyte; Step S2, using the conductive substrate material as the working electrode, the graphite rod as the counter electrode, and the silver / silver chloride electrode as the reference electrode; Step S3, placing the working electrode, the counter electrode, and the reference electrode in the electrolyte prepared in step S1, applying voltage to the working electrode at room temperature for anodic oxidation deposition, and after a period of deposition, the surface of the conductive base material will gradually be covered with deposited black oxide; Step S4, washing the working electrode obtained after step S3 with ultrapure water, and then drying it in an oven, thereby obtaining an electrode covered with the lead dioxide water electrolysis catalyst doped with the transition metal element.

[0009] Furthermore, in step S1, the lead salt precursor is lead nitrate, and the transition metal salt precursor is manganese and cobalt nitrate.

[0010] Further, in step S1, the lead salt precursor is one of Pb(NO3)2, Pb(ClO4)2, and Pb(CH3COO)2; And / or, the transition metal salt precursor is one or more of Mn(NO3)2, Fe(NO3)2, Co(NO3)2, and Ni(NO3)2.

[0011] Furthermore, in step S2, the conductive base material is one of antimony-doped tin oxide conductive glass, fluorine-doped tin oxide conductive glass, carbon paper, and carbon cloth.

[0012] Furthermore, the ultrasound is set to a frequency of 12kHz to 24kHz, the total power of the ultrasound equipment used is 2000W, the output power is 20% to 50% of the total power, and the ultrasound duration is 10min to 30min; And / or, in step S3, when performing anodization deposition, the applied voltage is 1.8 V vs Ag / AgCl, and the deposition time is 1800 s.

[0013] According to the technical solution of the present invention, the present invention also provides an application of a transition metal element-doped lead dioxide water electrolysis catalyst for catalyzing oxygen evolution reaction in an acidic environment.

[0014] Compared with the prior art, the beneficial technical effects of the present invention are as follows: 1. The base material PbO2 in the catalyst of the present invention has excellent conductivity. There is interaction between the doped transition metal elements such as Co, Mn and Pb, which optimizes the internal electronic structure of the catalyst and reduces the overpotential of OER. Compared with single PbO2, the activity of the catalyst is greatly improved.

[0015] 2. The catalyst matrix material PbO2 is extremely stable in an acidic environment. Therefore, the catalyst is difficult to be corroded by high potential and acidic environment during catalytic oxygen evolution and has excellent stability.

[0016] 3. The lead and transition metal elements in the catalyst are cheap, which greatly reduces the manufacturing cost of the anode oxygen evolution catalyst in the proton exchange membrane water electrolysis technology.

[0017] 4. The present invention is synthesized by a simple anodic oxidation deposition method, with low equipment cost and operation cost, and is easy to realize industrial mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is the XRD pattern of the catalyst prepared in Example 1 of the present invention.

[0019] Figure 2 This is the SEM image of the catalyst prepared in Example 1 of the present invention.

[0020] Figure 3 This is a graph of the catalytic activity of the catalyst prepared in Example 1 of the present invention in oxygen evolution reaction in 0.5 MH2SO4 measured by chronopotentiometry in a three-electrode system.

[0021] Figure 4 This is a graph of the catalytic stability of the catalyst prepared in Example 1 of the present invention in the oxygen evolution reaction in 0.5 MH2SO4 measured by chronopotentiometry in a three-electrode system. DETAILED DESCRIPTION

[0022] The present invention provides a transition metal element doped lead dioxide water electrolysis catalyst and a preparation method and application thereof, which solves the problem of high cost of existing anode catalysts, achieves good OER catalytic activity and stability, and has a simple and easy preparation process, thereby greatly reducing the cost of anode materials in proton exchange membrane water electrolysis technology.

[0023] The lead dioxide electrolysis catalyst doped with transition metal elements of the present invention comprises lead, oxygen and transition metal elements, wherein the transition metal elements are one or more of manganese, iron, cobalt and nickel. Preferably, the lead dioxide electrolysis catalyst doped with transition metal elements is CoMn-PbO x , that is, lead oxide doped with cobalt and manganese elements. The catalyst of the present invention exhibits high activity in catalyzing oxygen evolution reaction under acidic conditions.x For example, at 10 mA cm -2 The overpotential at 490 mV is 490 mV. The catalyst of the present invention exhibits high stability when catalyzing the oxygen evolution reaction under acidic conditions. x For example, at 10 mA cm -2 The catalytic activity can be stable for 20 h.

[0024] The present invention also provides a method for preparing a transition metal element-doped lead dioxide water electrolysis catalyst, which is used to prepare the transition metal element-doped lead dioxide water electrolysis catalyst of the present invention, and comprises the following steps S1 to S4.

[0025] Step S1, adding a lead salt precursor and a transition metal salt precursor to a nitric acid solution, obtaining a uniform solution after ultrasonic treatment, and using the solution as an electrolyte to be used in the following steps.

[0026] Wherein, in some embodiments, the lead salt precursor is one of Pb(NO3)2, Pb(ClO4)2, and Pb(CH3COO)2. In some embodiments, the transition metal salt precursor is one or more of Mn(NO3)2, Fe(NO3)2, Co(NO3)2, and Ni(NO3)2. Preferably, the lead salt precursor is lead nitrate, specifically Pb(NO3)2, and the transition metal salt precursor is manganese and cobalt nitrate, specifically Co(NO3)2 and Mn(NO3)2. In some embodiments, the ultrasound is set to a frequency of 12kHz to 24kHz, the total power of the ultrasonic equipment used is 2000W, the output power is 20% to 50% of the total power, and the ultrasound duration is 10min to 30min.

[0027] Step S2, using the conductive substrate material as the working electrode, a graphite rod (graphite) as the counter electrode, and a silver / silver chloride (Ag / AgCl) electrode as the reference electrode.

[0028] Among them, preferably, the conductive base material is one of antimony-doped tin oxide (ATO) conductive glass, fluorine-doped tin oxide (FTO) conductive glass, carbon paper, and carbon cloth.

[0029] Step S3, placing the working electrode, the counter electrode, and the reference electrode in the electrolyte prepared in step S1, applying voltage to the working electrode at room temperature for anodizing deposition, and after a period of deposition, the surface of the conductive base material will gradually be covered with deposited black oxide.

[0030] Preferably, during the anodic oxidation deposition, the applied voltage is 1.8 V vs Ag / AgCl, and the deposition time is 1800 s.

[0031] Step S4, washing the working electrode obtained after step S3 with ultrapure water for several times, and then drying it in an oven, thereby obtaining an electrode covered with the lead dioxide water electrolysis catalyst doped with the transition metal element.

[0032] Furthermore, the present invention also provides an application of the transition metal element-doped lead dioxide water electrolysis catalyst to catalyze oxygen evolution reaction in an acidic environment.

[0033] The technical solution of the present invention is further described below in conjunction with specific embodiments, but the content of the present invention is not limited to the following embodiments.

[0034] Embodiment 1: Step S1, adding 0.05 M Pb(NO3)2, 0.025 M Co(NO3)2 and 0.025 M Mn(NO3)2 to 0.1 M HNO3 solution, obtaining a uniform solution after ultrasonic treatment, and using the solution as an electrolyte; Step S2, using antimony-doped tin oxide (ATO) conductive glass as a base working electrode, a graphite rod (graphite) as a counter electrode, and a silver / silver chloride (Ag / AgCl) electrode as a reference electrode; Step S3, placing the above-mentioned electrode in the electrolyte prepared in step S1, applying a certain voltage to the working electrode at room temperature (e.g., about 20°C to 25°C) for anodic oxidation deposition, the voltage is 1.8 V vs Ag / AgCl, the deposition time is 1800s, and during the deposition process, the surface of the ATO conductive glass will be gradually covered with deposited black oxide; Step S4, washing the electrode obtained in step S3 with ultrapure water for several times, and then drying it in an oven at 60°C, thereby obtaining an electrode covered with a catalyst.

[0035] The crystal structure of the catalyst material obtained above is Figure 1 The XRD diffraction spectrum in the figure shows that it is β-PbO2, the diffraction peaks corresponding to each crystal plane are obvious, and the crystallinity is good.

[0036] The catalyst material is obtained by Figure 2 The SEM photos in Figure 2 show that the catalyst surface is irregular and contains voids and gaps.

[0037] Embodiment 2: The preparation steps and conditions are basically the same as those in Example 1, except that 0.025 M Co(NO3)2 and 0.025 M Mn(NO3)2 in step S1 are replaced by 0.05 M Co(NO3)2.

[0038] Embodiment 3: The preparation steps and conditions are basically the same as those in Example 1, except that 0.025 M Co(NO3)2 and 0.025 M Mn(NO3)2 in S1 are replaced by 0.05 M Mn(NO3)2.

[0039] Application Example 1: The transition metal element-doped lead dioxide obtained in Example 1 of the present invention is used to catalyze the oxygen evolution reaction in an acidic electrolyte. In a three-electrode test system, a graphite rod is selected as a counter electrode, silver / silver chloride is selected as a reference electrode, and 0.5 molL - 1 H2SO4 is the electrolyte.

[0040] The electrocatalytic oxygen evolution performance of the samples was tested by chronopotentiometry with current density values ​​set to 1, 10, 20, 30, 40 and 50 mA cm -2 ; The stability of the catalyst obtained in Example 1 of the present invention was tested by chronopotentiometry, where the current density was set to 10 mA cm -2 .

[0041] The test results show that the catalytic activity of the catalyst material prepared above is good, reaching 10 mA cm in 0.5 M H2SO4 solution. -2 The overpotential required for the current density is only 440 mV; the catalytic stability of the catalyst material prepared above is good, and the overpotential is 10 mA cm -2 At a current density of 1.5 Å, the catalytic activity can be maintained for more than 20 h.

[0042] In summary, the present invention synthesizes a transition metal element doped lead dioxide electrode by an anodic oxidation deposition method, wherein lead dioxide is used as a matrix material, has better conductivity, and has better stability in an acidic solution; the doped transition metal element is used as an active element for the oxygen evolution reaction, which improves the catalytic activity of the catalyst for the oxygen evolution reaction in an acidic solution. The present invention achieves higher stability and activity of the acidic oxygen evolution catalyst, reduces the manufacturing cost of the proton exchange membrane anode material; the manufacturing process is simple and easy, and has the potential for large-scale production. Therefore, the present invention has higher economic benefits and application value.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention; for ease of description, only the parts related to the relevant inventions are shown in the accompanying drawings. In the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other; modifying the technical solutions recorded in the aforementioned embodiments, or replacing some of the technical features therein by equivalents, does not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A transition metal element-doped lead dioxide water electrolysis catalyst, characterized in that: Its element composition is lead, oxygen and transition metal elements, wherein the transition metal elements are one or more of manganese, iron, cobalt and nickel.

2. The transition metal element-doped lead dioxide water electrolysis catalyst according to claim 1, characterized in that: It is CoMn-PbO x .

3. The transition metal element-doped lead dioxide water electrolysis catalyst according to claim 2, characterized in that: It exhibits high catalytic activity for oxygen evolution reaction under acidic conditions, with a catalytic activity of 10 mA cm -2 The overpotential is 490 mV.

4. The transition metal element-doped lead dioxide water electrolysis catalyst according to claim 2, characterized in that: It exhibits high stability in catalyzing oxygen evolution reaction under acidic conditions, with a -2 The catalytic activity can be stable for 20 h.

5. A method for preparing a transition metal element-doped lead dioxide water electrolysis catalyst, characterized in that: It is used to prepare the transition metal element-doped lead dioxide water electrolysis catalyst according to claim 1, and comprises the following steps: Step S1, adding a lead salt precursor and a transition metal salt precursor to a nitric acid solution, obtaining a uniform solution after ultrasonic treatment, and using the solution as an electrolyte; Step S2, using the conductive substrate material as the working electrode, the graphite rod as the counter electrode, and the silver / silver chloride electrode as the reference electrode; Step S3, placing the working electrode, the counter electrode, and the reference electrode in the electrolyte prepared in step S1, applying voltage to the working electrode at room temperature for anodic oxidation deposition, and after a period of deposition, the surface of the conductive base material will gradually be covered with deposited black oxide; Step S4, washing the working electrode obtained after step S3 with ultrapure water, and then drying it in an oven, thereby obtaining an electrode covered with the lead dioxide water electrolysis catalyst doped with the transition metal element.

6. The transition metal element-doped lead dioxide water electrolysis catalyst according to claim 5, characterized in that: In step S1, the lead salt precursor is lead nitrate, and the transition metal salt precursor is manganese and cobalt nitrate.

7. The transition metal element-doped lead dioxide water electrolysis catalyst according to claim 5, characterized in that: In step S1, the lead salt precursor is one of Pb(NO3)2, Pb(ClO4)2, and Pb(CH3COO)2; And / or, the transition metal salt precursor is one or more of Mn(NO3)2, Fe(NO3)2, Co(NO3)2, and Ni(NO3)2.

8. The transition metal element-doped lead dioxide water electrolysis catalyst according to claim 5, characterized in that: In step S2, the conductive base material is one of antimony-doped tin oxide conductive glass, fluorine-doped tin oxide conductive glass, carbon paper, and carbon cloth.

9. The transition metal element-doped lead dioxide water electrolysis catalyst according to claim 5, characterized in that: In step S1, the ultrasound is set to a frequency of 12kHz to 24kHz, the total power of the ultrasonic equipment used is 2000W, the output power is 20% to 50% of the total power, and the ultrasound duration is 10min to 30min; And / or, in step S3, when performing anodization deposition, the applied voltage is 1.8 V vs Ag / AgCl, and the deposition time is 1800 s.

10. Use of the transition metal element-doped lead dioxide water electrolysis catalyst according to any one of claims 1 to 4 to catalyze oxygen evolution reaction in an acidic environment.

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