Preparation method of ORR catalyst
阅读说明：本技术 Orr催化剂的制备方法 (Preparation method of ORR catalyst ) 是由 梁茜 王诚 王海峰 王利生 于 2019-09-18 设计创作，主要内容包括：本发明提供一种ORR催化剂的制备方法。该ORR催化剂的制备方法包括以下步骤：1)制作含钴多氮型金属有机框架材料的前驱体；2)将前驱体分散于含氯铂酸的乙二醇溶液中,进行微波合成/萃取反应,制得含有铂参与后配位的钴多氮型金属有机框架材料；3)铂参与后配位的钴多氮型金属有机框架材料进行煅烧处理,得到ORR催化剂。采用基于Pt增强多氮型咪唑羧酸类钴基金属有机框架材料,通过氧化还原方式制备电催化剂,操作工艺简单；同时降低了催化剂中铂含量,制得的催化剂金属有机框架具有微孔结构,有助于质子和气体的传输,产品具有较高的催化性能。(The invention provides a preparation method of an ORR catalyst. The preparation method of the ORR catalyst comprises the following steps: 1) preparing a precursor of the cobalt-containing multi-nitrogen metal organic framework material; 2) dispersing the precursor in a glycol solution containing chloroplatinic acid, and performing microwave synthesis/extraction reaction to prepare a cobalt multi-nitrogen type metal organic framework material containing platinum for coordination; 3) and calcining the coordinated cobalt multi-nitrogen type metal organic framework material after platinum participates to obtain the ORR catalyst. The Pt-based enhanced multi-nitrogen imidazole carboxylic acid cobalt-based metal organic framework material is adopted to prepare the electrocatalyst in an oxidation-reduction mode, so that the operation process is simple; meanwhile, the content of platinum in the catalyst is reduced, the prepared metal organic framework of the catalyst has a microporous structure, the transmission of protons and gas is facilitated, and the product has high catalytic performance.)
1. A preparation method of an ORR catalyst is characterized by comprising the following steps:
1) preparing a precursor of the cobalt-containing multi-nitrogen metal organic framework material;
2) dispersing the precursor in a glycol solution containing chloroplatinic acid, and performing microwave synthesis/extraction reaction to prepare a cobalt multi-nitrogen type metal organic framework material containing platinum for coordination;
3) and calcining the coordinated cobalt multi-nitrogen type metal organic framework material after platinum participates to obtain the ORR catalyst.
2. The method according to claim 1, wherein the step 1) is:
dissolving cobalt salt and 2- (p-N-imidazolyl) phenyl-1H-4, 5-imidazole dicarboxylic acid ligand in a mixed solvent, adjusting the pH value of the solution to be acidic, and carrying out hydrothermal reaction to obtain the cobalt-containing multi-nitrogen type metal organic framework material precursor.
3. The preparation method of claim 2, wherein the pH value of the solution is adjusted to 2-4, and the hydrothermal reaction is carried out at 140-155 ℃ for 48-96 h.
4. The method according to claim 2 or 3, wherein the cobalt salt is CoCl2·6H2O or Co (NO)3)2·6H2And O, and/or the mixed solvent is formed by uniformly mixing water and acetonitrile in a volume ratio of 4-8: 1-3.
5. The preparation method of claim 1, wherein in the step 2), the molar ratio of the precursor to the chloroplatinic acid-containing glycol solution is 1: 0.01-1.
6. The method according to claim 1 or 5, wherein the precursor is dispersed in a glycol solution containing chloroplatinic acid, and the microwave synthesis/extraction reaction is carried out by heating the mixture to 110 to 120 ℃ in an inert gas atmosphere for 15 to 20 minutes.
7. The preparation method according to claim 6, wherein the reaction system is sequentially subjected to centrifugation, water washing and vacuum drying after the microwave synthesis/extraction reaction is completed and then cooled to 30-45 ℃.
8. The preparation method according to claim 1, wherein in the step 3), the cobalt polynitrogen type metal organic framework material with platinum participating in post-coordination is heated to 300-500 ℃ in an inert gas atmosphere and is kept warm for 1-2 hours.
9. The method according to claim 8, wherein the heating is performed at a temperature rise rate of 2 to 3 ℃/min.
10. The preparation method according to claim 8 or 9, characterized in that the calcined product is sequentially subjected to ultrasonic washing with an organic solvent, water washing to neutrality and drying treatment.
Technical Field
The invention belongs to the technical field of oxidation-reduction electrocatalysis, and particularly relates to a preparation method of an ORR catalyst.
Background
The development of human civilization has been advanced to date, and the importance of energy is self-evident as the human society continues to advance at a high rate. With the continuous use of the three major ore energy sources, the problems of energy storage, excessive mining, environmental pollution and the like become more serious. Although each energy technological innovation and breakthrough has a great influence on the development of productivity and social change, all the social progress is built on the basis of using a large amount of fossil fuel to date. In the face of the demand for energy sources for global economy and population growth, and the increasing exhaustion of traditional energy sources, and the gradual deterioration of human living environment, the development of clean renewable new energy sources is the only way to maintain human sustainable development.
The hydrogen energy has the advantages of cleanness, high efficiency, environmental friendliness and the like, and is considered as an ideal energy source in the 21 st century. In addition, the bulk of hydrogen is in the form of compound water, and about 70% of the earth's surface is covered with water, so hydrogen is an "inexhaustible" energy source. As such, the united states, japan, etc. have been developing hydrogen fuel cells in our country, for example, the united states has established a national hydrogen energy development route as early as 2002, and japan is implementing a new solar plan to develop hydrogen energy economy. A fuel cell, which is an energy conversion device that can directly convert chemical energy into electrical energy as a hydrogen energy utilization technology, has high conversion efficiency, and the electrochemical reaction process thereof is a process of generating water by a hydrogen-oxygen reaction.
Proton Exchange Membrane Fuel Cells (PEMFCs) are green, efficient, and high-energy-density energy conversion devices, which can directly convert chemical energy into electric energy, and have the advantages of fast start, no pollution, and conversion efficiency up to 40%. The core component of the PEMFC is a Membrane Electrode (MEA), which is formed by hot pressing a proton exchange membrane having catalytic activity and a Gas Diffusion Layer (GDL). The performance of the MEA as a place for electrochemical reaction directly determines the conversion efficiency of the fuel cell, and also determines the performance, lifetime, and cost of the product. The electrochemical reaction performance of the MEA is mainly determined by the catalytic activity, specific surface area and electrochemical stability of the catalyst. According to the U.S. Department of Energy (DOE) report, it is shown that platinum (Pt) as a redox catalyst in the catalyst layer occupies 17% of the total cost of an 80kW PEMFC stack for a vehicle. Therefore, how to newly design a Catalyst Layer (CL) under the background of "high current density, low platinum loading, and low humidification" is becoming the leading edge of the current PEMFC research because the platinum loading is reduced while the high power density is realized.
The redox reaction (ORR) is the basic reaction of the cathode in a proton exchange membrane fuel cell, and currently, the commercial Pt/C catalyst is the most commonly used ORR electrocatalyst. However, Pt reserves are limited in nature and expensive, resulting in fuel cells that cannot be commercially used on a large scale. Over the past decades, scientists have developed different kinds of electrocatalysts, for example, non-noble metals and electrocatalysts free of metallic materials. Among these ORR catalytic materials, Metal Organic Frameworks (MOFs) have been applied to the fields of proton conduction and electrocatalysis due to their advantages such as higher porosity, larger specific surface area, and tunable and variable channel structure, and hetero atoms (B, N, S, P, etc.) prepared by using the metal organic frameworks as precursors can enhance the electrocatalysis activity after being doped into a carbon matrix or combined with metal/metal oxide, but none of the effects is ideal.
Disclosure of Invention
Therefore, the technical problem to be solved by the present invention is to provide a method for preparing an ORR catalyst, which can reduce the Pt content in the catalyst and has high catalytic performance.
In order to solve the above problems, the present invention provides a method for preparing an ORR catalyst, comprising the steps of:
1) preparing a precursor of the cobalt-containing multi-nitrogen metal organic framework material;
2) dispersing the precursor in a glycol solution containing chloroplatinic acid, and performing microwave synthesis/extraction reaction to prepare a cobalt multi-nitrogen type metal organic framework material containing platinum for coordination;
3) and calcining the coordinated cobalt multi-nitrogen type metal organic framework material after platinum participates to obtain the ORR catalyst.
Preferably, step 1) is:
dissolving cobalt salt and 2- (p-N-imidazolyl) phenyl-1H-4, 5-imidazole dicarboxylic acid ligand in a mixed solvent, adjusting the pH value of the solution to be acidic, and carrying out hydrothermal reaction to obtain the cobalt-containing multi-nitrogen type metal organic framework material precursor.
Preferably, the pH value of the solution is adjusted to 2-4, and the hydrothermal reaction is carried out for 48-96 h at 140-155 ℃.
Preferably, the cobalt salt is CoCl2·6H2O or Co (NO)3)2·6H2And O, and/or the mixed solvent is formed by uniformly mixing water and acetonitrile in a volume ratio of 4-8: 1-3.
Preferably, in the step 2), the molar ratio of the precursor to the ethylene glycol solution containing chloroplatinic acid is 1: 0.01-1.
Preferably, the precursor is dispersed in a glycol solution containing chloroplatinic acid, and is heated to 110-120 ℃ in an inert gas atmosphere to carry out microwave synthesis/extraction reaction for 15-20 minutes.
Preferably, after the microwave synthesis/extraction reaction is finished, cooling to 30-45 ℃, and sequentially centrifuging, washing and vacuum drying the reaction system.
Preferably, in the step 3), the cobalt multi-nitrogen type metal organic framework material coordinated after platinum participates is heated to 300-500 ℃ in an inert gas atmosphere, and the temperature is kept for 1-2 hours.
Preferably, the heating process is carried out at a heating rate of 2-3 ℃/min.
Preferably, the calcined product is sequentially subjected to ultrasonic washing by an organic solvent, water washing to neutrality and drying treatment. .
The invention provides a preparation method of an ORR catalyst, which comprises the following steps: 1) preparing a precursor of the cobalt-containing multi-nitrogen metal organic framework material; 2) dispersing the precursor in a glycol solution containing chloroplatinic acid, and performing microwave synthesis/extraction reaction to prepare a cobalt multi-nitrogen type metal organic framework material containing platinum for coordination; 3) and calcining the coordinated cobalt multi-nitrogen type metal organic framework material after platinum participates to obtain the ORR catalyst. The Pt-based enhanced multi-nitrogen imidazole carboxylic acid cobalt-based metal organic framework material is adopted to prepare the electrocatalyst in an oxidation-reduction mode, so that the operation process is simple; meanwhile, the content of platinum in the catalyst is reduced, the prepared metal organic framework of the catalyst has a microporous structure, the transmission of protons and gas is facilitated, and the product has high catalytic performance.
Drawings
FIG. 1 is an XRD pattern of a cobalt-based metal organic framework synthesized according to an example of the present invention; the measured curve is a synthetic product, and the simulated curve is a simulated product;
FIG. 2 is SEM images of Co-MNMOF, Pt/Co-MNMOF and Pt/Co-NC prepared by the embodiment of the invention, which respectively correspond to FIG. 2(a), FIG. 2(b) and FIG. 2 (c);
FIG. 3 is an HR-TEM image (high resolution TEM image) of Pt/Co-NC nanoparticles prepared according to an example of the present invention; it can be seen that the Pt/Co-NC catalyst particles are uniformly dispersed;
FIG. 4 shows examples of Co-MNMOF, Pt/Co-NC catalysts in N2Saturated 0.1M HClO4Comparison of Cyclic Voltammetry (CV) profiles in the electrolyte;
FIG. 5 is a graphical representation of a Pt/Co-NC and commercial 20% Pt/C catalyst of an example of the invention in N2Saturated 0.1M HClO4CV diagram comparison in electrolyte;
FIG. 6 shows Co-MNMOF, Pt/Co-NC catalysts in O according to an embodiment of the present invention2Saturated 0.1M HClO4Comparison of oxygen reduction (ORR) curves in electrolytes;
FIG. 7 shows examples of Pt/Co-NC and commercial 20% Pt/C catalysts of the invention in O2Saturated 0.1M HClO4Oxygen reduction (ORR) comparison in electrolyte.
Detailed Description
The invention provides a preparation method of a Pt-enhanced multi-nitrogen imidazole carboxylic acid cobalt-based metal organic framework material oxidation-reduction electrocatalyst for reducing the using amount of limited Pt resources, and the basic reaction principle of the preparation method is shown in the following equation:
chemical formula [ Co (p-IPhHIDC)]n
Chemical formula Pt/Co-MNMOF
The preparation method of the ORR catalyst has the following technical scheme that the preparation method comprises the following steps:
1) dissolving a cobalt salt and a 2- (p-N-imidazolyl) phenyl-1H-4, 5-imidazole dicarboxylic acid ligand in water and an acetonitrile solvent, performing ultrasonic treatment, stirring and mixing, adding an acid to adjust the pH value of the solution to 2-4, and performing hydrothermal reaction at the constant temperature of 140-155 ℃ for 48-96 hours; after cooling to room temperature, sequentially washing and naturally airing the obtained product to generate a black green transparent cobalt-containing multi-nitrogen metal organic framework material precursor (chemical formula: Co (p-IPhHIDC) ] n);
2) the precursor material [ Co (p-IPhHIDC) prepared in the step 1) is added]nUltrasonic dispersing in chloroplatinic acid (H) after fully grinding2PtCl6·6H2O) in glycol solution, placing the mixed solution in a microwave synthesis extraction reactor at 110-120 ℃, carrying out batch reaction for 15-20 min, and adding N2Making protective gas; cooling to about 30-45 ℃, taking out, sequentially centrifuging, washing and vacuum drying the reacted solution to obtain Pt/Co-MNMOF black solid powder with Pt participating in post-coordination;
3) in N2Under the atmosphere, the Pt/Co-MNMOF powder obtained in the step 2) is reducedAnd (3) carrying out warm calcination for 1-2 h, ultrasonically washing the obtained powder with an organic solvent, repeatedly carrying out centrifugal washing with water until the powder is neutral, and drying to obtain the target product Pt/Co-NC.
In the step 1), the mixing volume ratio of water to acetonitrile in the mixed solvent of water and acetonitrile is 4-8: 1-3.
In the step 2), the molar ratio of the precursor to the chloroplatinic acid ethylene glycol solution is 1: 0.01-1.
In step 3), putting the black solid powder of Pt/Co-MNMOF in N2And heating to 300-500 ℃ at the heating rate of 2-3 ℃/min in an atmosphere tube furnace, preserving heat for 1.5h, cooling to room temperature at the cooling rate of 1 ℃/min, and washing. Wherein the organic solvent used for ultrasonic washing is acetone or ethanol.
In order to more clearly illustrate the objects and technical solutions of the present invention, the following detailed description is given by way of specific examples.
- 上一篇：一种医用注射器针头装配设备
- 下一篇：一种电池模组的堆叠小车