阅读说明：本技术 一种Pr改性的Co-B催化剂的制备方法及应用 (Preparation method and application of Pr modified Co-B catalyst ) 是由 刘莹 苏彦铭 张欢 于 2019-09-12 设计创作，主要内容包括：本发明公开了一种Pr改性的Co-B催化剂的制备方法及应用,制备包括以下步骤：在室温常压下,用钴源前驱物和镨源前驱物配置成溶液A,用还原剂配置成溶液B；磁力搅拌下将溶液B缓慢滴加至溶液A中,将得到的黑色悬浮液离心,洗涤,干燥后获得催化剂产品。本发明的一种Pr改性Co-B催化剂主要应用于催化水解硼氢化钠制氢。本发明的有益之处在于：催化剂的活性组分是钴,价格合理,产品活性高。稀土元素Pr的掺杂避免了催化剂的团聚,促进纳米颗粒的分散,使更多的活性位点暴露,增强了催化剂的催化性能,且催化剂材料有磁性,易于分离回收利用。本发明所属催化剂的制备方法,生产流程短,工艺简单。(the invention discloses a preparation method and application of a Pr modified Co-B catalyst, wherein the preparation method comprises the following steps: preparing a solution A from a cobalt source precursor and a praseodymium source precursor at room temperature and normal pressure, and preparing a solution B from a reducing agent; slowly dripping the solution B into the solution A under magnetic stirring, centrifuging the obtained black suspension, washing and drying to obtain the catalyst product. The Pr modified Co-B catalyst is mainly applied to catalytic hydrolysis of sodium borohydride to produce hydrogen. The invention has the advantages that: the active component of the catalyst is cobalt, the price is reasonable, and the product activity is high. The rare earth element Pr is doped, so that the agglomeration of the catalyst is avoided, the dispersion of nano particles is promoted, more active sites are exposed, the catalytic performance of the catalyst is enhanced, and the catalyst material is magnetic and is easy to separate, recycle and utilize. The preparation method of the catalyst has the advantages of short production flow and simple process.)

1. A preparation method of a Pr modified Co-B catalyst is characterized in that the catalyst consists of cobalt, praseodymium and boron, and the structural formula of the catalyst is Co_x-Pr_(2-x)-B, wherein x is 2, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.2, 0. The method comprises the following steps:

(1) Cobalt praseodymium precursors in different proportions are taken and put into a round-bottom flask, and are uniformly mixed at room temperature and normal pressure.

(2) Adding a certain amount of sodium borohydride into the round-bottom flask, and carrying out reduction reaction for 3-5 min.

(3) And centrifuging the black suspension, washing and drying to obtain a catalyst sample.

2. The preparation method of the Pr-modified Co-B catalyst according to claim 1, wherein the preparation method of the catalyst for hydrogen production by catalytic hydrolysis of sodium borohydride comprises the following steps:

(1) Preparing a solution A by using a cobalt source precursor and a praseodymium source precursor at room temperature and normal pressure; preparing solution B by using a reducing agent; the molar ratio of the cobalt source precursor to the praseodymium source precursor is 2-0: 0-2;

(2) Slowly dropwise adding the solution B into the mixed solution A, and magnetically stirring for 3-5min at room temperature under normal pressure to obtain a black suspension catalyst;

(3) And centrifuging the black suspension, washing and drying to obtain a catalyst sample.

3. The method for preparing a Pr-modified Co-B catalyst according to claim 1, wherein the cobalt source precursor used is cobalt chloride hexahydrate, cobalt nitrate hexahydrate, or cobalt sulfate heptahydrate; the praseodymium source precursor is praseodymium nitrate hexahydrate.

4. The method of claim 1, wherein the molar ratio of the cobalt source precursor to the praseodymium source precursor is 2-0: 0-2.

5. The method of claim 1, wherein the optimal molar ratio of the cobalt source precursor to the praseodymium source precursor is 1.6: 0.4.

6. The method of claim 1, wherein the reducing agent is sodium borohydride or potassium borohydride.

7. An application of Pr modified Co-B catalyst in preparing hydrogen by catalytic hydrolysis of sodium borohydride.

8. Pr-modified C according to claim 7the application of the o-B catalyst in the hydrogen production by catalytic hydrolysis of sodium borohydride is characterized in that the catalyst is added with 5 percent (wt) of NaOH and 2.5 percent (wt) of NaBH into the solution during the catalytic hydrolysis of sodium borohydride₄The reaction solution of (1).

Technical Field

The invention particularly relates to a preparation method and application of a Pr modified Co-B catalyst, belonging to the field of environmental catalysis.

Background

Sodium borohydride (NaBH)₄) Is an environment-friendly hydrogen storage material, the theoretical hydrogen storage capacity of the material can reach 10.8 percent, and the material is an ideal hydrogen storage material. Generally, sodium borohydride can produce hydrogen gas by pyrolysis or hydrolysis. Pyrolysis is typically carried out at elevated temperatures, but high temperature conditions limit its use; hydrolysis reaction occurs relatively easily, and sodium metaborate (NaBO) is a by-product of the hydrolysis reaction₂) Is nontoxic and can be recycled and regenerated, but the reaction rate of the hydrogen production by hydrolysis is slower. In this case, a catalyst is required which can efficiently catalyze hydroborationThe hydrolysis reaction of sodium can accelerate the hydrogen production rate.

noble metals of platinum, rhodium and ruthenium have good catalytic activity for the hydrolysis of sodium borohydride, but the high cost and scarcity of these catalysts limit the application of the catalysts in practical commercial industries. Non-noble metal catalysts such as cobalt, nickel, copper and alloys thereof, in which Co-B is a good catalyst, are inexpensive and exhibit high catalytic activity, but generally Co-B exhibits disadvantages of low specific surface area, poor thermal stability and agglomeration. At present, many researches are biased to Co-B alloy catalysts improved by transition metals and rare earth elements, and the combination of multiple metals can generate a synergistic effect so as to improve the catalytic performance of a single metal. Zou Yongjin and the like adopt sodium borohydride as a reducing agent to prepare the Co-Ce-B nano catalyst by adopting a Co-reduction method, and the addition of Ce improves the dispersion degree of the catalyst and improves the activity of the catalyst. Ce and Pr are lanthanide, so the application of the rare earth element provides a new idea for the research of the catalyst, and the low price and the relatively abundant resource of the rare earth element provide possibility for the industrial application of the catalyst for catalyzing the hydrolysis of sodium borohydride to prepare hydrogen.

disclosure of Invention

In order to solve the defects of the prior art, the invention designs the Pr modified Co-B catalyst, the preparation method of the invention is simple, the operation is easy, the price is reasonable, the catalyst has high catalytic activity, and the catalyst material has magnetism and is easy to separate, recycle and utilize.

In order to achieve the above purpose, the invention adopts the following technical scheme:

A preparation method of a Pr modified Co-B catalyst is characterized in that the catalyst consists of cobalt, praseodymium and boron, and the structural formula of the catalyst is Co_x-Pr(_2-x)-B, wherein x-2, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.2, 0. The method comprises the following steps:

(1) And (3) taking the cobalt source precursor and the praseodymium source precursor in different proportions, and uniformly mixing at room temperature in a round-bottom flask.

(2) And adding a certain amount of sodium borohydride into the round-bottom flask, and reducing for 3-5min to obtain the black suspended liquid catalyst.

(3) And centrifuging the black suspension, washing and drying to obtain a catalyst sample.

The preparation method of the Pr modified Co-B catalyst is characterized in that the preparation method of the catalyst for catalyzing hydrolysis of sodium borohydride comprises the following steps:

(1) Preparing a solution A by using a cobalt source precursor and a praseodymium source precursor at room temperature and normal pressure; preparing solution B by using a reducing agent; the mass ratio of the cobalt source precursor liquid to the praseodymium source precursor is 2-0: 0-2.

(2) Slowly dropwise adding the solution B into the mixed solution A, and magnetically stirring for 3-5min at room temperature under normal pressure to obtain a black suspended liquid catalyst.

(3) And centrifuging the black suspension, washing and drying to obtain a catalyst sample.

The preparation method of the Pr-modified Co-B catalyst is characterized in that the cobalt source precursor is cobalt chloride hexahydrate, cobalt nitrate hexahydrate or cobalt sulfate heptahydrate; the praseodymium source precursor is praseodymium nitrate hexahydrate.

The preparation method of the Pr modified Co-B catalyst is characterized in that the molar ratio of the cobalt source precursor to the praseodymium source precursor is 2-0: 0-2.

The preparation method of the Pr modified Co-B catalyst is characterized in that the optimal molar ratio of the cobalt source precursor to the praseodymium source precursor is 1.6: 0.4.

The preparation method of the Pr modified Co-B catalyst is characterized in that the reducing agent is sodium borohydride or potassium borohydride.

The Pr-modified Co-B catalyst is characterized by being prepared by the method.

An application of Pr modified Co-B catalyst in catalyzing the hydrolysis of sodium borohydride to prepare hydrogen.

the application of the Pr modified Co-B catalyst in hydrogen production by catalytic hydrolysis of sodium borohydride is characterized in that the catalyst is used for adding 5% (wt) NaOH and 2.5% (wt) NaBH into a solution in advance when the catalyst is used for catalytic hydrolysis of sodium borohydride₄The reaction solution of (1).

the invention has the advantages that: cobalt is a transition element, is less expensive than noble metals, and has significantly better activity than other elements than other non-noble metals. The praseodymium is doped, so that the dispersion degree of the catalyst is well improved, the agglomeration of catalyst particles is reduced, more active sites are exposed outside, the activity of the catalyst is improved, and the catalyst material is magnetic and is easy to separate, recycle and utilize.

Drawings

FIG. 1 influence of Co/Pr ratio on hydrogen production performance by catalytic hydrolysis of sodium borohydride

FIG. 2 Co_1.6-Pr_0.4TEM image of-B catalyst

FIG. 3 Co_1.6-Pr_0.4Stability Performance test of the-B catalyst

Detailed Description

A preparation method of a Pr modified Co-B catalyst is characterized in that the catalyst consists of cobalt, praseodymium and boron, and the structural formula of the catalyst is Co_x-Pr(_2-x)-B, wherein x-2, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.2, 0. The method comprises the following steps:

(1) And (3) taking nickel source precursors and praseodymium source precursors in different proportions, and uniformly mixing at room temperature in a round-bottom flask.

(2) and adding a certain amount of sodium borohydride into the round-bottom flask, and reducing for 3-5min to obtain the black suspended liquid catalyst.

(3) And centrifuging the black suspension, washing and drying to obtain a catalyst sample.

The cobalt source precursor is cobalt chloride hexahydrate, cobalt nitrate hexahydrate or cobalt sulfate heptahydrate;

The praseodymium source precursor is praseodymium nitrate hexahydrate;

The molar ratio of the cobalt source precursor to the praseodymium source precursor is 2-0: 0-2;

The optimal molar ratio of the cobalt source precursor to the praseodymium source precursor is 1.6: 0.4;

the reducing agent is sodium borohydride or potassium borohydride;

The solvent dissolving the cobalt source precursor, the praseodymium source precursor and the reducing agent is distilled water.

the invention relates to a method for preparing hydrogen by catalyzing and hydrolyzing sodium borohydride with Pr modified Co-B catalyst, which comprises the following steps:

(1) 20mg of catalyst and deionized water were added to the round bottom flask, which was set in a constant temperature magnetic stirring water bath.

(2) To a round bottom flask was added 2.5mL of 5% (wt) NaOH and 2.5% (wt) NaBH₄reaction solution of (2)

(3) The reaction was started and the hydrogen production volume was measured by the water displacement method.

the method of the invention can be used for preparing products with a series of properties and specifications.

the following describes specific embodiments of the present invention, but the present invention is not limited to the specific embodiments;