阅读说明：本技术 一种铁/钨双金属有机框架阳极析氧复合材料及其制备方法 (Iron/tungsten bimetal organic frame anode oxygen evolution composite material and preparation method thereof ) 是由 王海人 魏飞飞 王麒钧 赵雪竹 于超奇 尹习习 刘战祥 于 2019-04-08 设计创作，主要内容包括：本发明属于新能源材料技术领域,具体涉及一种铁/钨双金属有机框架阳极析氧复合材料及其制备方法。更具体地,涉及一种引入亚铁离子与钨离子来构筑的金属有机框架(MOF)阵列及其制备方法。该制备方法包括如下步骤：(1)将泡沫镍(NF)放进入盐酸溶液中以去除表面的氧化镍等杂质,提升反应物在泡沫镍表面的附着力,取出洗涤后干燥表面水分,得到活化的泡沫镍载体；(2)将铁盐与钨盐按照一定的摩尔量称取,并取一定量的配体,溶于溶剂后,将(1)中获得的泡沫镍载体浸入溶液中,溶剂热反应获得具备柱状结构的铁基金属有机框架复合材料。该新型双功能电化学催化剂具有优良的电化学催化性能和稳定性。(The invention belongs to the technical field of new energy materials, and particularly relates to an iron/tungsten bimetal organic frame anode oxygen evolution composite material and a preparation method thereof. And more particularly, to a Metal Organic Framework (MOF) array constructed by introducing ferrous ions and tungsten ions and a preparation method thereof. The preparation method comprises the following steps: (1) putting the foamed Nickel (NF) into a hydrochloric acid solution to remove impurities such as nickel oxide on the surface, improving the adhesive force of reactants on the surface of the foamed nickel, taking out and washing the reactant, and drying the surface moisture to obtain an activated foamed nickel carrier; (2) weighing ferric salt and tungsten salt according to a certain molar weight, taking a certain amount of ligand, dissolving in a solvent, immersing the foamed nickel carrier obtained in the step (1) into the solution, and carrying out solvothermal reaction to obtain the iron-based metal organic framework composite material with the columnar structure. The novel bifunctional electrochemical catalyst has excellent electrochemical catalytic performance and stability.)

1. An iron/tungsten bimetal organic frame anode oxygen evolution composite material and a preparation method thereof are characterized in that the preparation method comprises the following working procedures:

step (i) for preparing a porous nickel foam material: taking a commercially available three-dimensional porous foamed nickel material;

step (II), preparing an activated three-dimensional porous foamed nickel material substrate:

activating the three-dimensional porous nickel foam material in a hydrochloric acid solution to remove an oxide film on the surface of the three-dimensional porous nickel foam material, and then taking out and drying to obtain an activated three-dimensional porous nickel foam material substrate;

step three, preparation of the iron/tungsten bimetallic organic framework/foamed nickel composite material:

the working procedure is that the iron/tungsten bimetallic organic frame/foamed nickel composite material is prepared by one-step synthesis in a high-pressure reaction kettle through a solvothermal method on the activated three-dimensional porous foamed nickel material substrate prepared in the working procedure (II).

2. The method of claim 1, wherein the step (iii) of preparing the "iron/tungsten bimetallic organic framework/foamed nickel composite material" comprises the following 3 steps:

step 1: preparing raw materials:

taking tungsten chloride (chemical purity), ferrous chloride tetrahydrate (chemical purity) and 2, 5-dihydroxy terephthalic acid (chemical purity), wherein the weight ratio of tungsten chloride: 50mg to 300mg, ferrous chloride tetrahydrate: 20-300 mg, 2, 5-dihydroxyterephthalic acid: 60mg, required: fixing the amount of the ligand, and changing the ratio of iron salt (ferrous chloride tetrahydrate) to tungsten salt (tungsten chloride) into 0-1: 1-0 (molar ratio);

taking a solvent: DMF: 20ml, deionized water: 1.5ml, absolute ethanol: 1.5ml, namely: the solvent ratio is DMF, deionized water and ethanol: 20: 1.5;

step 2: preparing reaction equipment:

high-pressure reactor, specification and model: 25ml of polytetrafluoroethylene inner container;

and step 3: preparation of MOF material:

(1) adding 20ml of DMF, 1.5ml of deionized water and 1.5ml of ethanol into a high-pressure reaction kettle;

(2) then weighing tungsten chloride, ferrous chloride tetrahydrate and 2, 5-dihydroxy terephthalic acid, and respectively adding the tungsten chloride, the ferrous chloride tetrahydrate and the 2, 5-dihydroxy terephthalic acid into a reaction kettle; completely dissolving by ultrasonic to obtain suspension;

(3) immersing the activated three-dimensional porous foamed nickel in the step (II) into the suspension, and carrying out solvothermal reaction for 24 hours at 120 ℃ to obtain an iron/tungsten bimetallic organic frame/foamed nickel material with an array-shaped structure;

(4) taking out and naturally airing to obtain the 'iron/tungsten bimetal organic frame anode oxygen evolution composite material' of the invention, namely: an iron/tungsten bimetallic organic framework/foamed nickel composite MOF material. The composite material takes three-dimensional porous foamed nickel as a framework, and an iron/tungsten bimetal organic framework/foamed nickel array composite material is generated on the surface and inside of the foamed nickel framework.

3. The method for preparing the iron/tungsten bimetallic organic framework/foamed nickel composite material according to claim 2, wherein the raw materials used in the preparation method are as follows: the tungsten salt is preferably tungsten hexachloride, the ferric salt is preferably ferrous chloride tetrahydrate, the ligand is 2, 5-dihydroxy terephthalic acid, and the solvent is selected from DMF, deionized water and ethanol: 20: 1.5.

4. The method for preparing the iron/tungsten bimetallic organic framework/foamed nickel composite material according to claim 2, wherein the ratio of the iron salt (ferrous chloride tetrahydrate) to the tungsten salt (tungsten hexachloride) in the step 1 is 0-1: 1-0 (molar ratio) of iron salt to tungsten salt.

5. The iron/tungsten bimetallic organic frame anode oxygen evolution composite material and the preparation method thereof as claimed in claim 1, wherein the 'iron/tungsten bimetallic organic frame anode oxygen evolution composite material' is an 'iron/tungsten bimetallic organic frame/nickel foam array composite material', the composite material takes three-dimensional porous nickel foam as a skeleton, and the iron/tungsten bimetallic organic frame/nickel foam array is generated on the surface and inside of the nickel foam skeleton.

Technical Field

The invention belongs to the technical field of new energy materials, and particularly relates to an iron/tungsten bimetal organic frame anode oxygen evolution composite material and a preparation method thereof.

Background

The first class of MOFs was synthesized as early as the 90's of the 20 th century, but its porosity and chemical stability were not high. Thus, scientists have begun investigating novel cationic, anionic and neutral ligand-forming coordination polymers. At present, a large number of metal organic framework materials are synthesized, mainly by carboxyl-containing organic anionic ligands or by using nitrogen-containing heterocyclic organic neutral ligands together. Many of these metal-organic frameworks have high porosity and good chemical stability. In recent years, Metal Organic Framework (MOF) and its derivative nano-materials have the characteristics of high porosity, large specific surface area, regular periodic structure, diversity of metal center and ligand, adjustable functionalization and the like, and have attracted great research interest in the fields of catalysis, energy storage, conversion and the like.

Today, there are many methods for making MOF materials, mainly:

(1) a solvent method: in the presence of water or organic solvent, a stainless steel high-pressure reaction kettle or a glass test tube with a polytetrafluoroethylene lining is used for heating a raw material mixture, and a high-quality single crystal is obtained by reaction under the self pressure;

(2) liquid phase diffusion method: mixing metal salt, organic ligand and proper solvent according to a certain proportion, putting the mixture into a small glass bottle, putting the small glass bottle into a large bottle, putting a protonized solvent into the large glass bottle, sealing the bottle cap, standing, and generating MOFs crystals after a period of time;

(3) other methods are as follows: many new production methods have been developed in recent years, including sol-gel method, stirring synthesis method, solid phase synthesis method, microwave, ultrasonic wave, and ion thermal method.

The MOFs (metal-organic frameworks) is a porous material with high specific surface area, can be used for designing inorganic and organic framework materials on a molecular level, and has wide application prospects in the field of high-capacity supercapacitors. However, most MOFs are too poor in conductivity and severely affect the performance of the energy storage device. Thus, electrically conductive MOFs have emerged, which consist of semiconductors and conductors hybrid-formed from coordination polymers such as strong metal ligand orbitals. 2D and 3D MOFs have more pores and more redox active sites than 1D. However, the intrinsic energy density of the framework material is too low, which limits the theoretical energy density increase of the redox active sites thereof, thereby reducing the volume capacity and mass capacity thereof.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a novel high-efficiency oxygen evolution electrochemical catalyst composite material and a preparation method thereof, the method fully combines the characteristics of the novel high-efficiency oxygen evolution electrochemical catalyst composite material, the preparation process of the composite material is designed in a brand-new way, the key process parameters and the raw material types in the preparation process are selected and optimized, and the novel bifunctional electrochemical high-efficiency catalyst composite material with good conductivity, stability, high strength and other excellent comprehensive properties is correspondingly prepared, namely: a novel MOFs material of iron/tungsten bimetallic organic framework/foamed nickel. The material has proven to be an excellent electrocatalytic material for large scale electrolytic oxygen production. The design concept of the present invention can be easily extended to other electrocatalytic applications, including electrocatalytic reduction of CO₂The oxygen reduction reaction and the hydrogen evolution or oxygen evolution reaction widen the application prospect of the electrochemical catalyst composite material.

The technical scheme of the invention is realized as follows:

the invention provides an iron/tungsten bimetal organic frame anode oxygen evolution composite material and a preparation method thereof, wherein the preparation method comprises the following steps: a preparation method of an iron/tungsten bimetallic organic framework/foamed nickel composite material comprises the following steps:

a first step: preparing a porous nickel foam material: taking a commercially available foam three-dimensional porous nickel foam material, and comprising the following components: the nickel content is 99.8%; specification size: 250mm 200mm 1 mm; surface density: 320g/m²±20

A second step: preparing an activated three-dimensional porous foamed nickel material carrier:

the formula of the activating solution is as follows: HCl with a concentration of 1-10 mol/L

The activation process comprises the following steps: the temperature is 25-60 ℃ and the time is 1-45 min.

And (3) activating the three-dimensional porous foamed nickel material according to the formula and the process, removing oxide skin on the surface of the three-dimensional porous foamed nickel material, taking out and drying to obtain the activated three-dimensional porous foamed nickel material carrier.

A third step of: preparing an iron/tungsten bimetallic organic framework/foamed nickel composite material:

the working procedure is that the activated three-dimensional porous foamed nickel material substrate prepared in the working procedure (II) is subjected to one-step synthesis in a high-pressure reaction kettle by a solvothermal method to prepare the organic frame iron/tungsten bimetal anode oxygen evolution composite material.

The process further comprises the following 3 steps:

step 1: preparing raw materials:

taking tungsten chloride (chemical purity), ferrous chloride tetrahydrate (chemical purity) and 2, 5-dihydroxy terephthalic acid (chemical purity), wherein the weight ratio of tungsten chloride: 50mg to 300mg, ferrous chloride tetrahydrate: 20-300 mg, 2, 5-dihydroxyterephthalic acid: 60mg, required: fixing the amount of the ligand, and changing the ratio of iron salt (ferrous chloride tetrahydrate) to tungsten salt (tungsten chloride) into 0-1: 1-0 (molar ratio);

taking a solvent: DMF: 20ml, deionized water: 1.5ml, absolute ethanol: 1.5ml, namely: the solvent ratio is DMF, deionized water and ethanol: 20: 1.5.

Step 2, preparing experimental equipment:

high-pressure reactor, specification and model: 25ml, polytetrafluoroethylene inner container.

And step 3: preparation of MOF material:

(1) adding 20ml of DMF, 1.5ml of deionized water and 1.5ml of ethanol into a high-pressure reaction kettle;

(2) then weighing tungsten chloride, ferrous chloride tetrahydrate and 2, 5-dihydroxy terephthalic acid, and respectively adding the tungsten chloride, the ferrous chloride tetrahydrate and the 2, 5-dihydroxy terephthalic acid into a reaction kettle; completely dissolving by ultrasonic to obtain suspension;

(3) and (3) immersing the activated three-dimensional porous nickel foam in the step (II) into the suspension, and carrying out solvothermal reaction for 24h at 120 ℃ to obtain the iron/tungsten bimetallic organic framework/nickel foam material with an array structure.

(4) Taking out and naturally airing to obtain the 'iron/tungsten bimetal organic frame anode oxygen evolution composite material' of the invention, namely: an iron/tungsten bimetallic organic framework/foamed nickel composite MOF material. The composite material is a composite material which takes three-dimensional porous foamed nickel as a framework, and an iron/tungsten bimetallic organic framework/foamed nickel array is generated on the surface and inside of the foamed nickel framework (as shown in figure 3).

Electrochemical test results:

the prepared MOF material is used for a working electrode of an OER linear cyclic voltammetry test, and the excellent oxygen evolution performance is embodied.

In summary, compared with the prior art, the above technical solution contemplated by the present invention can achieve the following beneficial effects:

(1) the invention provides a preparation method of a novel efficient oxygen evolution electrochemical catalyst composite material, which is characterized in that a metal organic framework array grows in situ on a three-dimensional porous foam nickel carrier at a certain temperature by a solvothermal method, so that the growth of a nano array is controlled, the specific surface area of the material is greatly increased, and the performances of the material in the aspects of electronic transmission and the like are improved.

(2) The iron/tungsten bimetallic organic framework/foamed nickel composite material prepared by the solvothermal method, the metal salt, the ligand and the components on the surface of the three-dimensional porous foamed nickel material are tightly combined through chemical bonds to form the composite material, and the composite material has good stability.

(3) The iron/tungsten bimetallic organic frame/foamed nickel composite material has a good OER anodic oxidation reaction electrochemical catalysis function, has a high-current effect, and has excellent electrochemical catalysis stability in an OER linear cyclic voltammetry test.

(4) The preparation method of the iron/tungsten bimetallic organic frame/foamed nickel composite material provided by the invention is simple, rapid and safe, and the prepared material does not need subsequent treatment. Therefore, the invention provides the iron/tungsten bimetallic organic framework/foamed nickel composite material with industrial application prospect and the preparation method thereof, and the composite material can be used for catalyzing, energy storage and CO₂The method has wide prospect in the application fields of reduction, photoelectricity and the like.

Drawings

FIG. 1 is a schematic flow chart of the preparation process of the iron/tungsten bimetallic organic frame/foamed nickel composite material;

FIG. 2 is a photograph of a sample taken from different samples during preparation;

FIG. 3 is a Scanning Electron Microscope (SEM) image of an iron/tungsten bimetallic organic framework/nickel foam composite;

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

The invention provides a preparation method of an iron/tungsten bimetal organic frame/foamed nickel composite material, which comprises the following steps:

a first step: taking a commercially available foam three-dimensional porous nickel foam material, and comprising the following components: the nickel content is 99.8%; specification size: 250mm 200mm 1 mm; surface density: 320g/m²±20

A second step: preparing an activated three-dimensional porous foamed nickel material carrier:

the formula of the activating solution is as follows: HCl with a concentration of 1-10 mol/L

The activation process comprises the following steps: the temperature is 25-60 ℃ and the time is 1-45 min.

And (3) activating the three-dimensional porous foamed nickel material according to the formula and the process, removing oxide skin on the surface of the three-dimensional porous foamed nickel material, taking out and drying to obtain the activated three-dimensional porous foamed nickel material carrier.

A third step of: preparing an iron/tungsten bimetallic organic framework/foamed nickel composite material:

step 1: preparing raw materials:

tungsten hexachloride: 50mg to 300mg, ferrous chloride tetrahydrate: 20-300 mg, 2, 5-dihydroxyterephthalic acid: 60 mg; DMF: 20ml, deionized water: 1.5ml, absolute ethanol: 1.5ml

Step 2: preparing a high-pressure reaction kettle, wherein the specification and the model are as follows: 25ml, polytetrafluoroethylene inner container.

And step 3: preparation of MOF material:

(1) adding 20ml of DMF, 1.5ml of deionized water and 1.5ml of ethanol into a high-pressure reaction kettle;

(2) weighing tungsten hexachloride, ferrous chloride tetrahydrate and 2, 5-dihydroxy terephthalic acid, and respectively adding the tungsten hexachloride, the ferrous chloride tetrahydrate and the 2, 5-dihydroxy terephthalic acid into a reaction kettle; completely dissolving by ultrasonic to obtain suspension;

(3) and (3) immersing the activated three-dimensional porous nickel foam in the step (II) into the suspension, and carrying out solvothermal reaction for 24h at 120 ℃ to obtain the iron/tungsten bimetallic organic framework/nickel foam material with an array structure.

(4) Taking out and naturally airing to obtain the iron/tungsten bimetallic organic framework/foamed nickel composite MOF material.

The following are examples: