阅读说明：本技术 一种钴氮杂石墨烯基催化剂催化氨硼烷产氢性能的研究 (Research on hydrogen production performance of ammonia borane catalyzed by cobalt-nitrogen-doped graphene-based catalyst ) 是由 马晓艳 高庆玲 张洋 胡莉 郝杰 张旭梅 于 2019-09-30 设计创作，主要内容包括：本发明公开了一种钴氮杂石墨烯基催化剂催化氨硼烷产氢性能的研究。氨硼烷除用作高能储氢材料外,近年来氨硼烷及其衍生物在有机合成化学领域还可用作还原剂用于醛酮、羰基化合物的还原反应,与传统还原剂相比具有反应条件温和、选择性强、产物收率高等优点。氨硼烷化合物(NH<Sub>3</Sub>BH<Sub>3</Sub>)是新近得到密切关注的一种新型化学氢化物储氢材料,它具有超高的氢密度(19.6wt％),热稳定性和化学稳定性良好等优点而具有广阔的应用前景。其中在T＝298K、15％NaOH下氨硼烷产氢速率最快,TOF值为54moL<Sub>H2</Sub>.min<Sup>-1</Sup>.moL<Sub>Ca</Sub><Sup>-1</Sup>,表观活化能为27.1kJ/mol,其中金属钴的负载量为1-2％wt,该催化剂的成功制备对氨硼烷产氢有着重大意义。(The invention discloses a research on the performance of catalyzing ammonia borane to produce hydrogen by using a cobalt aza graphene-based catalyst. Besides being used as a high-energy hydrogen storage material, ammonia borane and derivatives thereof can also be used as a reducing agent in the field of organic synthetic chemistry for reduction reaction of aldehyde ketone and carbonyl compounds in recent years, and compared with the traditional reducing agent, the ammonia borane has the advantages of mild reaction conditions, strong selectivity, high product yield and the like. Ammonia borane compound (NH) 3 BH 3 ) The material is a novel chemical hydride hydrogen storage material which is recently and closely focused, and has the advantages of ultrahigh hydrogen density (19.6 wt%), good thermal stability and chemical stability and the like, thereby having wide application prospect. Wherein the ammonia borane has the fastest hydrogen production rate under the conditions of T298K and 15 percent NaOH, and the TOF value is 54moL H2 .min ‑1 .moL Ca ‑1 The apparent activation energy is 27.1kJ/mol, the loading of metallic cobalt is 1-2 wt%, and the catalyst is successfully preparedHas great significance for producing hydrogen from ammonia borane.)

1. A research on the hydrogen production performance of ammonia borane catalyzed by a cobalt-nitrogen-doped graphene-based catalyst is characterized by comprising the following specific steps:

s1, preparing the cobalt-nitrogen-doped graphene-based catalyst, which comprises the following steps:

weighing urea, phthalic anhydride, ammonium molybdate and cobalt chloride hexahydrate in a 500mL beaker, placing the beaker in an oil bath kettle at a certain temperature for heating and stirring, cooling to room temperature after a sample reaches a molten state, placing the sample in a microwave oven for heating for a period of time, taking out the sample, cooling to room temperature, grinding, adding a sodium hydroxide solution with a certain volume and concentration, boiling for 30min, carrying out suction filtration, washing to be neutral, drying and grinding; dissolving the dried product with concentrated sulfuric acid, diluting with deionized water, filtering, washing to neutrality, drying, and grinding to obtain cobalt phthalocyanine; calcining cobalt phthalocyanine at high temperature to obtain a cobalt aza graphene-based catalyst;

s2, catalyzing ammonia borane to produce hydrogen by using the cobalt aza graphene-based catalyst, the method comprises the following steps:

adding a certain amount of catalyst, reaction substrate and solvent into a two-neck flask, designing experiments under different conditions by using a controlled variable method, and inspecting the influence of the catalyst on the ammonia borane hydrolysis rate under different conditions.

2. The method of claim 1, wherein the cobalt aza-graphene-based catalyst is prepared according to S1, wherein the mass of urea, phthalic anhydride, ammonium molybdate, and cobalt chloride hexahydrate is 27g, 16.8g, 1.5g, and 5.7 g.

3. The method for preparing the cobalt-aza-graphene-based catalyst in S1 according to claim 1, wherein the oil bath temperature is 100 ℃ and 120 ℃, and the reaction time in microwave is 6-8 min.

4. The method of claim 1, S1, wherein the cobalt aza graphene-based catalyst is prepared with a sodium hydroxide volume of 340mL and a concentration of 20%.

5. The method of preparing a cobalt aza graphene-based catalyst as claimed in S1, wherein the loading of cobalt is 1-2%.

6. In the experiment of producing hydrogen by catalyzing ammonia borane with the cobalt aza graphene-based catalyst according to the claim 1 in S2, the designed conditions are sodium hydroxide concentration, catalyst concentration, concentration of aqueous solution, ammonia borane concentration, temperature and catalyst cycling stability experiment.

Technical Field

The invention belongs to the field of catalysts, and particularly relates to a preparation method of a non-noble metal catalyst and research on hydrogen production performance of ammonia borane.

Background

In recent years, with the rapid development of global economy, the demand of human beings on energy sources accelerates the consumption of non-renewable energy sources such as coal, petroleum, natural gas and the like, and also causes serious pollution to the global environment, and the hydrogen energy has the advantages of rich content, high fuel value, reproducibility, no pollution and the like and is paid attention to by people. Ammonia borane (NH)₃BH₃AB for short, has a high hydrogen storage density (19.6%) and a low molecular weight (30.9 gmol)^-1) It is one of the chemical hydride hydrogen storage materials with the highest hydrogen storage capacity. Meanwhile, the development and utilization of hydrogen energy have received high attention from researchers, but the storage and utilization of hydrogen gas have been faced with great challenges. The most critical problems are the difficulty in quickly and efficiently producing hydrogen and the safe storage of hydrogen. Hydrogen is one of the best expected energy carriers to meet the growing demand for clean and efficient energy supplies. The hydrogen production of ammonia borane can be realized by two modes of pyrolysis and hydrolysis, however, the pyrolysis method needs to be carried out at higher temperature, and the aqueous solution of ammonia borane is stable and can be quickly and easily hydrolyzed at room temperature to generate hydrogen in the presence of a proper catalyst.

In view of the above, the present invention is proposed to solve the above technical problems.

Disclosure of Invention

The invention aims to provide a research on the hydrogen production performance of ammonia borane catalyzed by a cobalt aza graphene-based catalyst, which adopts the cobalt aza graphene-based catalyst, has mild reaction conditions and high catalysis efficiency, and is suitable for the catalysis field.

A cobalt aza graphene based catalyst ammonia borane hydrogen production performance research comprises the following specific steps:

s1, preparing a cobalt nitrogen graphene-based catalyst;

and S2, catalyzing ammonia borane to produce hydrogen by using the cobalt aza graphene-based catalyst.

Further, the preparation method of the cobalt aza graphene-based catalyst in S1 comprises the specific steps of: putting urea, phthalic anhydride, ammonium molybdate and cobalt chloride hexahydrate in a 500mL beaker, heating and stirring in an oil bath kettle at a certain temperature, cooling to room temperature after a sample reaches a molten state, heating in a microwave oven for a period of time, taking out, cooling to room temperature, grinding, adding a sodium hydroxide solution with a certain volume and concentration, boiling for 30min, carrying out suction filtration, washing to be neutral, drying and grinding; dissolving the dried product with concentrated sulfuric acid, diluting with deionized water, filtering, washing to neutrality, drying, and grinding to obtain cobalt phthalocyanine; calcining cobalt phthalocyanine at high temperature to obtain a cobalt aza graphene-based catalyst;

further, in the preparation method of the cobalt aza graphene-based catalyst in S1, the mass of the urea, phthalic anhydride, ammonium molybdate and cobalt chloride hexahydrate in the step are 27g, 16.8g, 1.5g and 5.7g respectively;

further, in the preparation method of the cobalt-nitrogen-doped graphene-based catalyst in S1, the oil bath temperature in the step is 100-120 ℃, and the reaction time in microwave is 6-8 min;

further, in the preparation method of the cobalt aza graphene-based catalyst in S1, the volume of sodium hydroxide in the step is 340mL, and the concentration is 20%;

further, in the preparation method of the cobalt aza graphene-based catalyst in S1, the loading amount of cobalt in the step is 1-2%;

further, the cobalt aza graphene-based catalyst in S2 is used for catalyzing ammonia borane to produce hydrogen, and the specific steps are as follows: adding a certain amount of catalyst, reaction substrate and solvent into a two-mouth flask, designing experiments under different conditions by using a controlled variable method, and inspecting the influence of the catalyst on the ammonia borane hydrolysis rate under different conditions;

further, in the step S2, the cobalt aza graphene-based catalyst catalyzes ammonia borane to produce hydrogen, and the conditions designed in the step are sodium hydroxide concentration, catalyst concentration, concentration of aqueous solution, ammonia borane concentration, temperature, and catalyst cycling stability experiment.

The invention has the beneficial effects that:

1. in the research on the performance of catalyzing ammonia borane to generate hydrogen by using the cobalt aza graphene-based catalyst provided by the invention, the catalyst has high activity and high selectivity;

2. in the research on the performance of catalyzing ammonia borane to generate hydrogen by using the cobalt aza graphene-based catalyst provided by the invention, the preparation method of the catalyst is simple and easy to implement and has low cost;

3. the catalyst of the invention has less by-products in catalyzing ammonia borane to produce hydrogen, mild reaction conditions, simple and convenient operation and good reproducibility;

4. the raw material of the invention has high hydrogen storage density (19.6%) and low molecular weight (30.9g mol)^-1) No toxicity, high stability, environment friendship, etc.

Drawings

FIG. 1 is a graph of the effect of NaOH concentration on ammonia borane hydrolysis to produce hydrogen;

FIG. 2 is a graph of the effect of catalyst concentration on ammonia borane hydrolysis to produce hydrogen;

FIG. 3 is a graph of the effect of water concentration on ammonia borane hydrolysis to produce hydrogen;

FIG. 4 is a graph of the effect of ammonia borane concentration on ammonia borane hydrolysis to produce hydrogen;

FIG. 5 is a graph of the effect of temperature on ammonia borane hydrolysis to produce hydrogen;

FIG. 6 is a graph of the effect of catalyst recycle on ammonia borane hydrolysis to produce hydrogen;

fig. 7 is a Scanning Electron Microscope (SEM) image of a cobalt aza graphene-based catalyst.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings.