CN110625136A

CN110625136A - Method for efficiently and simply synthesizing Ru nanowire

Info

Publication number: CN110625136A
Application number: CN201910973926.1A
Authority: CN
Inventors: 张南; 王军梅; 张永亚; 刘猛; 陈亚; 魏伟; 瞿鹏
Original assignee: Shangqiu Normal University
Current assignee: Shangqiu Normal University
Priority date: 2019-10-14
Filing date: 2019-10-14
Publication date: 2019-12-31
Anticipated expiration: 2039-10-14
Also published as: CN110625136B

Abstract

The invention discloses a method for efficiently and simply synthesizing a Ru nanowire, which synthesizes the Ru nanowire with uniform appearance and good dispersibility by a hydrothermal method. Firstly, dissolving a certain amount of ruthenium trichloride hydrate and polyvinylpyrrolidone (PVP) in deionized water, stirring and mixing, adding a certain amount of sodium hypophosphite aqueous solution into the obtained mixed solution, stirring the obtained mixed solution at room temperature for 0.5 h, transferring the solution into a 25 mL stainless steel reaction kettle containing a polytetrafluoroethylene lining, sealing, and placing the stainless steel reaction kettle in an oven at 200 ℃ for reaction for 6 h. Naturally cooling to room temperature after the reaction is finished, adding acetone into the obtained black dispersion liquid for centrifugal separation, washing the obtained black precipitate with deionized water/acetone for three times, and finally dispersing in a mixed solution of water and ethanol for uniform dispersion by ultrasonic. The ruthenium nanowire obtained by the invention can be used as a cathode material for water electrolysis, and shows good hydrogen production performance in a wide pH range.

Description

Method for efficiently and simply synthesizing Ru nanowire

Technical Field

The invention belongs to the technical field of photoelectric functional materials, relates to an electro-catalytic material, and particularly relates to a method for efficiently and simply synthesizing Ru nanowires.

Background

Fossil fuels are the energy foundation for maintaining modern life, and the consumption of the fossil fuels is accelerated along with the growth of the world population and the continuous development of industrialization in recent decades. Also, the combustion of fossil fuels can emit carbon dioxide and other hazardous gases or airborne dust particles, resulting in serious environmental problems. Therefore, the development of clean and renewable fossil fuel alternative energy sources is crucial for sustainable development. Hydrogen energy is one of the ideal choices, and hydrogen can be produced by electrolyzing water. In the technical field of electrocatalytic hydrogen production, the catalyst Ru nanocrystalline is applied to a cathode material for water electrolysis due to the factors of low price, low overpotential, high current density, good stability and the like. In order to increase the efficiency of electrocatalytic hydrogen production, more demands are generally placed on the synthesized electrocatalytic material.

The cathode electrocatalyst is a key material of a water electrolysis hydrogen production system, and influences the efficiency of electrocatalytic hydrogen production. At present, ruthenium-based nano materials in electrolyte with wide pH range have excellent performance, although the ruthenium-based nano materials are electrolytic water cathode materials with excellent performance and stability, ruthenium nano crystals with different exposed crystal faces and different morphologies have different activity performances, and the simple synthesis of the ruthenium-based nano materials is the research direction. Aiming at the problem, reducing agents with different reducing degrees can be adopted for regulation and control, and the formation and growth of ruthenium crystal nucleus are controlled, so that the morphology of the ruthenium crystal nucleus is controlled.

Ru nanocrystals and derivatives thereof are widely used in a variety of important industrial catalytic reactions, including methanol oxidation, Fischer-Tropsch synthesis, activation of C-H bonds, etc. Ru has a metal-hydrogen bond strength (~ 65 kcal mol) similar to Pt^-1) Recently, ruthenium-based nanocrystals have been demonstrated as oneA promising catalyst for electrochemical hydrogen evolution reaction. The simple synthesis of the nano materials with different morphologies is a difficult point, and in the existing reports, the ruthenium (Ru) nanocrystals synthesized in water phase or polyhydric alcohol are all irregular-morphology nano polyhedral small particles, and the regulation and control of the synthesis of the ruthenium nano materials with different morphologies still needs to be further explored.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides the ruthenium nanowire with good water/ethanol phase dispersibility, uniform appearance and good electrocatalysis performance and the preparation method thereof.

In order to solve the technical problems, the invention adopts the following technical scheme:

a method for efficiently and simply synthesizing Ru nanowires synthesizes uniformly dispersed Ru nanowires at high temperature by utilizing the reduction effect of sodium hypophosphite in a water phase system, and comprises the following specific steps:

(1) dissolving ruthenium trichloride hydrate and polyvinylpyrrolidone (PVP) in deionized water, and stirring to obtain a mixed solution;

(2) adding a certain amount of sodium hypophosphite aqueous solution into the mixed solution obtained in the step (1);

(3) carrying out high-temperature hydrothermal reaction for 6 h, naturally cooling to room temperature after the reaction is finished, and adding acetone into the obtained black dispersion liquid for centrifugal separation to obtain black precipitate;

(4) the obtained black precipitate was washed three times with deionized water/acetone, and finally dispersed uniformly in a mixed solution of water and ethanol by ultrasound.

Further, in the step (1), the dosage of the hydrated ruthenium trichloride is 0.06 mmol, the dosage of the PVP is 80 mg, and the dosage of the deionized water is 13 mL.

Further, in the step (2), the concentration of the sodium hypophosphite aqueous solution is 1 mmol/L, and the dosage is 100 mu L.

Further, in the step (3), the reaction temperature is 200 ℃.

The invention has the beneficial effects that: the invention adopts a hydrothermal method, utilizes sodium hypophosphite as a reducing agent and controlsThe ruthenium nanometer crystal with the nanometer line shape is prepared and synthesized. The reducing agent sodium hypophosphite has specific input amount, and the formation and growth of ruthenium crystal nucleus are controlled by utilizing the reduction effect of the sodium hypophosphite. Finally obtaining the ruthenium nanometer wire. The ruthenium nanowire prepared by the invention can be used as an electrocatalytic hydrogen production material in the presence of 1M KOH, 0.1M KOH and 0.5M H₂SO₄And 10 mA cm in 1M PBS electrolyte^-2The overpotentials at current densities of (a) were 87, 124, 71 and 113 mV, respectively.

Drawings

FIG. 1 is an XRD pattern of ruthenium nanowires of example 1 of the present invention;

FIG. 2 is a TEM image of ruthenium nanowires of example 1 of the present invention;

FIG. 3 shows the results of the present invention in example 1, the ruthenium nanowires were treated with 1M KOH, 0.1M KOH, 0.5M 0.5M H₂SO₄And an electrolyzed water hydrogen production LSV curve in 1M PBS electrolyte.

Detailed Description

The present invention will be further described with reference to the following examples. It is to be understood that the following examples are illustrative only and are not intended to limit the scope of the invention, which is to be given numerous insubstantial modifications and adaptations by those skilled in the art based on the teachings set forth above.

Example 1

A method for efficiently and simply synthesizing Ru nanowires comprises the following steps:

(1) dissolving 0.06 mmol of ruthenium trichloride hydrate and 80 mg of polyvinylpyrrolidone (PVP) in deionized water, and stirring to obtain a mixed solution;

(2) adding 100 μ L of 1 mmol/L sodium hypophosphite solution into the above mixed solution, and stirring the obtained mixed solution for 0.5 h;

(4) carrying out high-temperature hydrothermal reaction at 200 ℃ for 6 h, naturally cooling to room temperature, adding acetone into the obtained black dispersion liquid, and carrying out centrifugal separation to obtain black precipitate;

(5) the obtained black precipitate was washed three times with deionized water/acetone, and finally dispersed uniformly in a mixed solution of water and ethanol by ultrasound.

As shown in FIG. 1, X-ray powder diffraction shows that the phase of the prepared ruthenium nanowire ishcpAnd (4) phase(s). Corresponding to JCPDS card number 06-0663, no impurity peak appears, which indicates that the product purity is higher.

As shown in figure 2, a transmission electron microscope image shows that ruthenium nanocrystals with a nanowire structure are obtained when sodium hypophosphite is used as a reducing agent, and the electrocatalytic performance of the ruthenium nanowires is tested by taking a certain volume of ruthenium nanowire dispersion liquid to be diluted to 1 mL (diluted by a mixed solvent with the volume ratio of water to ethanol being 3: 7), adding 30 mu L of Nafion (5 wt.%) solution, performing ultrasonic treatment for about 1 h to uniformly disperse the solution, taking 5 mu L of dispersed liquid to be naturally dried on a 3 mm glassy carbon electrode, taking the dispersed liquid as a working electrode, adopting a three-electrode system for electrochemical hydrogen evolution test, taking Ag/AgCl (saturated potassium chloride) as a reference electrode and a graphite rod as a counter electrode, and taking a hydrogen evolution reaction polarization curve obtained by a Linear Scanning Voltammetry (LSV) test, wherein the potential test range is-0.9 ~ -1.5V (LSV)vsAg/AgCl), the scanning speed was 5 mV/s. The potential values are fitted to the Reversible Hydrogen Electrode (RHE) potential according to the nernst equation.

E _RHE = E _Ag/AgCl + 0.059×pH + E ^θ _Ag/AgCl (0.197)

As shown in FIG. 3, in the presence of 1M KOH, 0.1M KOH, 0.5M 0.5M H₂SO₄And 1M PBS, the LSV curve of the ruthenium nanowires prepared in this example, FIG. 3 shows at 10 mA cm^-2The overpotentials at current densities of (a) were 87, 124, 71 and 113 mV, respectively.

The foregoing shows and describes the general principles and features of the present invention, together with the advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. A method for efficiently and simply synthesizing Ru nanowires is characterized by comprising the following steps:

(4) washing the black precipitate obtained in the step (3) with deionized water/acetone for three times, and finally uniformly dispersing the black precipitate in a mixed solution of water and ethanol by ultrasonic.

2. The method for efficiently and simply synthesizing Ru nanowires according to claim 1, which is characterized in that: in the step (1), the dosage of the hydrated ruthenium trichloride is 0.06 mmol, the dosage of the PVP is 80 mg, and the dosage of the deionized water is 13 mL.

3. The method for efficiently and simply synthesizing Ru nanowires according to claim 1, which is characterized in that: in the step (2), the concentration of the sodium hypophosphite aqueous solution is 1 mmol/L, and the dosage is 100 mu L.

4. The method for efficiently and simply synthesizing Ru nanowires according to claim 1, which is characterized in that: in the step (3), the reaction temperature is 200 ℃.