阅读说明：本技术 一种一锅法合成非贵金属氧还原、氧解析双效电催化剂 (One-pot synthesis of non-noble metal double-effect electrocatalyst for oxygen reduction and oxygen desorption ) 是由 朱威 马猛猛 庄仲滨 于 2019-10-18 设计创作，主要内容包括：本发明涉及一种运用g?C<Sub>3</Sub>N<Sub>4</Sub>的七嗪结构捕获螯合金属原子，形成Fe?N<Sub>x</Sub>和Ni?N<Sub>x</Sub>双活性位点，使催化剂同时具备氧还原和氧解析双效功能。该方法简单高效，通过将铁源、镍源与g?C<Sub>3</Sub>N<Sub>4</Sub>一锅混合，然后通过水热反应将铁、镍紧密螯合在g?C<Sub>3</Sub>N<Sub>4</Sub>的空位中，最后通过高温碳化，形成铁、镍的活性位点，从而得到一种同时具备氧还原和氧解析双效性能的非贵金属催化剂。该催化剂在碱性条件下性能优异，而且稳定性好，足以取代贵金属Pt/IrO<Sub>2</Sub>催化剂，具有很高的商业价值。(The invention relates to a method for applying g-C 3 N 4 The heptazine structure of (A) captures the chelated metal atom to form Fe-N x And Ni-N x The double active sites enable the catalyst to have double functions of oxygen reduction and oxygen analysis. The method is simple and efficient, and iron source, nickel source and g-C are mixed 3 N 4 Mixing in a pot, and then tightly chelating Fe and Ni in g-C by hydrothermal reaction 3 N 4 Finally, active sites of iron and nickel are formed through high-temperature carbonization in the vacant sites, so that the non-noble metal catalyst with double-effect performance of oxygen reduction and oxygen analysis is obtained. The catalyst has excellent performance and good stability under alkaline condition, and can replace noble metal Pt/IrO 2 The catalyst has high commercial value.)

1. A preparation process for synthesizing a non-noble metal double-effect electrocatalyst with oxygen reduction and oxygen analysis by a one-pot method comprises the following steps:

step 1) weighing 500g of urea in a magnetic boat, transferring the urea to a tube furnace in air atmosphere, and carbonizing the urea for 4 hours at 550 ℃ to obtain g-C ₃ N ₄ Weighing 500mg of g-C ₃ N ₄ Adding a certain amount of ferric salt and nickel salt into 75mL of ultrapure water, carrying out oil bath for a period of time at a certain temperature, then washing the obtained material with water for three times, transferring the washed material to a polytetrafluoroethylene lining, adding 20mL of glucose solution with a certain concentration, then carrying out hydrothermal treatment for a certain time at a certain temperature, then washing with water and ethanol for three times, and drying in a vacuum drying oven for 12 hours to obtain g-C ₃ N ₄ -Fe+Ni,

Step 2) adding g-C ₃ N ₄ Transferring Fe + Ni into a porcelain boat, calcining the porcelain boat in a tubular furnace in an inert atmosphere at a certain temperature for a certain time, naturally cooling to room temperature to obtain the non-noble metal electrocatalyst with the double-effect catalytic performances of oxygen reduction and oxygen desorption.

2. The method for preparing a double-effect non-noble metal electrocatalyst for oxygen reduction and oxygen dissociation reactions as claimed in claim 1, wherein the method comprises the following steps: the ferric salt in the step 1) can be one or two of ferric nitrate nonahydrate, ferric chloride hexahydrate, ferrous ammonium sulfate hexahydrate, ferrous sulfate, ferric sulfate, ferrous chloride tetrahydrate, ferrous acetate tetrahydrate, anhydrous ferrous chloride and anhydrous ferric chloride.

3. The method for preparing a double-effect non-noble metal electrocatalyst for oxygen reduction and oxygen dissociation reactions as claimed in claim 1, wherein the method comprises the following steps: the nickel salt in the step 1) can be one or two of nickel nitrate hexahydrate, nickel chloride hexahydrate, nickel sulfate hexahydrate, nickel nitrate hexahydrate, nickel acetylacetonate and nickel bromide.

4. The method for preparing a double-effect non-noble metal electrocatalyst for oxygen reduction and oxygen dissociation reactions as claimed in claim 1, wherein the method comprises the following steps: the temperature in step 1) may be 30-80 ℃.

5. The method as claimed in claim 1, wherein the method for preparing the double-effect non-noble metal electrocatalyst for oxygen reduction and oxygen dissociation reaction comprises the following steps: the period of time in step 1) may be 4 to 24 hours.

6. The method for preparing a double-effect non-noble metal electrocatalyst for oxygen reduction and oxygen dissociation reactions as claimed in claim 1, wherein the method comprises the following steps: the mixing in step 1) may be at a concentration of glucose of 0.2-1M.

7. The method as claimed in claim 1, wherein the method for preparing the double-effect non-noble metal electrocatalyst for oxygen reduction and oxygen dissociation reaction comprises the following steps: the temperature of the hydrothermal reaction in step 1) may be 100 to 200 ℃.

8. The method as claimed in claim 1, wherein the method for preparing the double-effect non-noble metal electrocatalyst for oxygen reduction and oxygen dissociation reaction comprises the following steps: the hydrothermal reaction time in step 1) may be 4-24h.

9. The method for preparing a double-effect non-noble metal electrocatalyst for oxygen reduction and oxygen dissociation reactions as claimed in claim 1, wherein the method comprises the following steps: the inert gas introduced into the high-temperature tube furnace in the step 2) can be argon or nitrogen, and the gas flow can be 30-120ml/min.

10. The method for preparing a double-effect non-noble metal electrocatalyst for oxygen reduction and oxygen dissociation reactions as claimed in claim 1, wherein the method comprises the following steps: the calcining process in the high-temperature tube furnace in the step 2) is a calcining process, wherein the temperature is increased to 150-250 ℃ at the speed of 1-10 ℃/min, and the temperature is kept for 0.5-3.0 hours; then the temperature is raised to 800-1000 ℃ at the speed of 1-5 ℃/min, and the temperature is preserved for 0.5-3.0 hours.

Technical Field

The invention relates to a non-noble metal catalyst which is synthesized by a one-pot method and simultaneously has iron and nickel double sites, and has high-efficiency catalytic performance when being applied to oxygen reduction and oxygen analysis. Using g-C ₃ N ₄ The heptazine structure captures chelated metal atoms, anchors iron and nickel in the hydrothermal process, simultaneously mixes glucose to further improve the carbon content, and finally forms Fe-N in the carbonization stage _x And Ni-N _x A double active site. The iron and nickel double sites are simultaneously prepared by the one-pot method, so that the high-efficiency non-noble metal catalyst with oxygen reduction and oxygen analysis is obtained, and the method has wide application prospect in the field of zinc-air batteries.

Background

Zinc-air batteries are considered to be one of the most promising energy storage and conversion devices due to their high conversion, environmental friendliness, and little emission of nitrogen oxides and sulfides. Zinc is a cheap metal resource, has abundant reserves on the earth, has the advantages of no toxicity, negative electrode potential and the like, and is always an anode widely applied to chemical power sources. The industrial production is started as early as 90 s in the 19 th century, and the anode material of the zinc-manganese battery which is still widely used globally at present is zinc. The zinc or zinc alloy is used as the anode of the fuel cell, and the cathode adopts air, so that the zinc-air cell is obtained by assembly. Zinc air cells are an energy conversion technology that is intermediate between fuel cells and conventional batteries. It has the design features of conventional cells with metallic zinc as the cathode, on the other hand, they are like fuel cells, with a porous anode structure that requires oxygen from the ambient air as a reactant. Theoretically, with oxygen in the air as the cathode, the positive electrode capacity is nearly infinite and outside the cell, the space within the cell can be filled with more anode material. Thus, zinc-air cells are the highest specific energy among zinc-type cells, up to 1086 Wh-kg-1 (including oxygen), and the cathode material is derived from air, with zero cost.

At present, the cathode oxygen reduction electrocatalysis of the zinc-air battery is mainly made of noble metals such as Pt and the like and alloys thereof. Although the oxygen reduction catalytic performance of the noble metal Pt catalyst is high, the noble metal Pt catalyst is expensive, scarce in resources and poor in stability, and the commercial development and application of the noble metal Pt catalyst are limited. Researches show that the functionalized carbon material can catalyze the oxygen reduction reaction, and the iron-nickel co-doped oxygen reduction and oxygen decomposition high-efficiency non-noble metal electrocatalyst is prepared by a one-pot method, so that the electrocatalyst not only has high-efficiency catalytic performance, but also is low in raw material cost, simple and high-efficiency. Since the active site of iron has the ability to catalyze the reduction of oxygen, the active site of nickel has the ability to catalyze the resolution of oxygen. Therefore, the bifunctional catalyst synthesized by the experiment is very suitable for the chargeable and dischargeable zinc-air battery.

Disclosure of Invention

The technical problem solved by the invention is as follows: by regulating the proportion of iron and nickel, g-C is utilized ₃ N ₄ The heptazine structure is subjected to one-pot reaction, so that the catalyst material with iron and nickel double sites is synthesized very accurately, and the catalyst material has high-efficiency catalytic capability of oxygen reduction and oxygen analysis. And the catalyst has low cost, and the synthesis method is simple and efficient. The problems of low catalytic performance, poor stability, high cost and difficulty in large-scale popularization of the chargeable and dischargeable zinc-air battery catalyst are solved.

The invention is realized by the following modes:

step 1) weighing 500g of urea in a magnetic boat, transferring the urea to a tube furnace in air atmosphere, and carbonizing the urea for 4 hours at a certain temperature to obtain g-C ₃ N ₄ Weighing a certain amount of g-C ₃ N ₄ Adding 75mL of ultrapure water into iron salt and nickel salt, performing oil bath for a period of time at a certain temperature, then washing the obtained material with water for three times, transferring the material to a polytetrafluoroethylene lining, adding 20mL of glucose solution with a certain concentration, performing hydrothermal treatment for a certain time at a certain temperature, then washing with water and ethanol for three times, and drying in a vacuum drying oven for 12 hours to obtain g-C ₃ N ₄ -Fe+Ni。

Step 2) adding g-C ₃ N ₄ Transferring Fe + Ni into a porcelain boat, calcining the porcelain boat in a tubular furnace in an inert atmosphere at a certain temperature for a certain time, naturally cooling to room temperature to obtain the non-noble metal electrocatalyst with the double-effect catalytic performances of oxygen reduction and oxygen desorption.

Further preferred is

In the step 1), the certain temperature is 30-80 ℃, and the optimal temperature is 60-80 ℃.

The reaction period in the step 1) is 4-24h, and is optimized to be 12-24h.

In the step 1), the mixing is carried out at a certain concentration of 0.2-1M glucose, preferably 0.6-1M glucose.

In the step 2), the calcining process in the high-temperature tube furnace is to heat up to 150-250 ℃ at the speed of 1-10 ℃/min and preserve heat for 0.5-3.0 hours; then the temperature is raised to 800-1000 ℃ at the speed of 1-5 ℃/min, and the temperature is preserved for 0.5-3.0 hours. The optimization is that the temperature is raised to 200-250 ℃ at the rate of 5 ℃ and is kept for 2-3.0 hours; then the temperature is raised to 800-1000 ℃ at the speed of 5 ℃/min, and the temperature is kept for 2.0-3.0 hours.

THE ADVANTAGES OF THE PRESENT INVENTION

The invention synthesizes the iron and nickel codoped double-effect non-noble metal electrocatalyst with oxygen reduction and oxygen desorption by using a one-pot method, the synthesis method is simple, and the prepared electrocatalyst not only has excellent catalytic performance of oxygen reduction and oxygen desorption, but also has good stability. Provides a new idea for preparing the zinc-air battery catalyst capable of being charged and discharged. Compared with the prior art, the invention has the following advantages:

1) The invention synthesizes the iron and nickel codoped bifunctional electrocatalyst by a one-pot method. The method is simple, low in cost and easy to popularize.

2) The invention obtains the Pt/IrO of which the performance of the catalyst is superior to that of the noble metal by introducing the non-noble metals of iron and nickel and accurately regulating and controlling the proportion of the iron and the nickel ₂ The catalyst has great economic value.

3) The invention obtains stable Fe-N through a carbonization step _x And Ni-N _x Double active sites, so that the electrocatalyst with extremely high stability is obtained, and the electrocatalyst is very suitable for being applied to a component of a zinc-air battery.

Drawings

FIG. 1 shows non-noble metals of iron and nickel (m) synthesized by a one-pot method in example 1 _{Iron (II)} ：m _{Nickel (II)} = 1:1) co-doped two-way electrocatalyst linear scanning voltammogram.

FIG. 2 shows non-noble metals of Fe and Ni (m) synthesized by one-pot method in comparative example 1 _Iron ：m _{Nickel (II)} Linear scanning voltammogram of 1.5).

FIG. 3 shows non-noble metals Fe and Ni (m) synthesized by one-pot method in comparative example 2 _{Iron (II)} ：m _{Nickel (II)} = 1.5) linear sweep voltammogram of co-doped two-way electrocatalyst.

FIG. 4 is a scheme of the one-pot synthesis of non-noble in example 1Metallic iron, nickel (m) _Iron ：m _{Nickel (II)} = 1:1) co-doped dual effect electrocatalyst transmission electron microscopy images.

FIG. 5 shows non-noble metals of Fe and Ni (m) synthesized by one-pot method in example 1 _{Iron (II)} ：m _{Nickel (II)} = 1:1) co-doped double effect electrocatalyst test pattern for zinc air cell.

Example 1

Step 1) weighing 500g of urea in a magnetic boat, transferring the urea to a tube furnace in air atmosphere, and carbonizing the urea for 4 hours at 550 ℃ to obtain g-C ₃ N ₄ Weighing 500mg of g-C ₃ N ₄ ，250mg FeCl ₃ ·6H ₂ O，250mg Ni(NO ₃ ) ₂ ·6H ₂ Adding 75mL of ultrapure water into O, carrying out oil bath at 70 ℃ for 12h, then washing the obtained material with water for three times, transferring the material to a polytetrafluoroethylene lining, adding 20mL of 0.6M glucose solution, then carrying out hydrothermal treatment at 140 ℃ for 12h, then washing with water and ethanol for three times, and drying the material in a vacuum drying oven for 12h to obtain g-C ₃ N ₄ -Fe+Ni。

Step 2) adding g-C ₃ N ₄ Transferring Fe + Ni into a porcelain boat, putting the porcelain boat into a tube furnace, heating the sample to 250 ℃ at a heating rate of 5 ℃/min in an inert atmosphere, keeping the sample at 250 ℃ for 2 hours under flowing argon, heating the sample to 900 ℃, keeping the sample at 900 ℃ for 2 hours under flowing argon, naturally cooling the sample to room temperature to obtain the non-noble metal electrocatalyst g-C with the double-effect catalytic performance of oxygen reduction and oxygen desorption ₃ N ₄ -Fe+Ni（1:1）。

Comparative example 1

Step 1) weighing 500g of urea in a magnetic boat, transferring the urea to a tube furnace in air atmosphere, and carbonizing the urea for 4 hours at 550 ℃ to obtain g-C ₃ N ₄ Weighing 500mg of g-C ₃ N ₄ ，375mg FeCl ₃ ·6H ₂ O，250mg Ni(NO ₃ ) ₂ ·6H ₂ Adding 75mL of ultrapure water into O, performing oil bath at 70 ℃ for 12h, then washing the obtained material with water three times, transferring the material to a polytetrafluoroethylene lining, and adding 0.6M glucose solutionHeating the solution 20mL, washing with water and ethanol at 140 deg.C for 12h, washing with water and ethanol for three times, and drying in vacuum drying oven for 12h to obtain g-C ₃ N ₄ -Fe+Ni。

Step 2) adding g-C ₃ N ₄ Transferring Fe + Ni into a porcelain boat, putting the porcelain boat into a tube furnace, heating the sample to 250 ℃ at a heating rate of 5 ℃/min in an inert atmosphere, keeping the sample at 250 ℃ for 2 hours under flowing argon, heating the sample to 900 ℃, keeping the sample at 900 ℃ for 2 hours under flowing argon, naturally cooling the sample to room temperature to obtain the non-noble metal electrocatalyst g-C with the double-effect catalytic performance of oxygen reduction and oxygen desorption ₃ N ₄ -Fe+Ni（1.5:1）。

Comparative example 2

Step 1) weighing 500g of urea in a magnetic boat, transferring the urea to a tube furnace in air atmosphere, and carbonizing the urea for 4 hours at 550 ℃ to obtain g-C ₃ N ₄ Weighing 500mg of g-C ₃ N ₄ ，250mg FeCl ₃ ·6H ₂ O，375mg Ni(NO ₃ ) ₂ ·6H ₂ Adding 75mL of ultrapure water into O, carrying out oil bath at 70 ℃ for 12h, then washing the obtained material with water for three times, transferring the material to a polytetrafluoroethylene lining, adding 20mL of 0.6M glucose solution, then carrying out hydrothermal treatment at 140 ℃ for 12h, then washing with water and ethanol for three times, and drying the material in a vacuum drying oven for 12h to obtain g-C ₃ N ₄ -Fe+Ni。

Step 2) adding g-C ₃ N ₄ Transferring Fe + Ni into a porcelain boat, putting the porcelain boat into a tube furnace, heating the sample to 250 ℃ at a heating rate of 5 ℃/min in an inert atmosphere, keeping the sample at 250 ℃ for 2 hours under flowing argon, heating the sample to 900 ℃, keeping the sample at 900 ℃ for 2 hours under flowing argon, naturally cooling the sample to room temperature to obtain the non-noble metal electrocatalyst g-C with the double-effect catalytic performance of oxygen reduction and oxygen desorption ₃ N ₄ -Fe+Ni（1:1.5）。