阅读说明：本技术 一种缺陷型钴酸镍/多孔碳的制备方法 (Preparation method of defective nickel cobaltate/porous carbon ) 是由 柴东凤 郭文鑫 曲孟榆 于 2021-07-13 设计创作，主要内容包括：本发明涉及一种缺陷型钴酸镍/多孔碳的制备方法。本发明的目的是要解决现有钴酸镍导电性较差和活性位点较少的问题,提供一种可提高其作为电催化析氢催化剂的制备方法。方法：以碱式碳酸镁、烟灰、氯化锌、硝酸镍、硝酸钴和尿素为原料,采用高温煅烧、水热及部分还原法,得到缺陷型钴酸镍/多孔碳复合材料,为提高现有钴酸镍电催化析氢性能提供了一种制备方法。(The invention relates to a preparation method of defective nickel cobaltate/porous carbon. The invention aims to solve the problems of poor conductivity and few active sites of the existing nickel cobaltate and provides a preparation method capable of improving the application of the nickel cobaltate as an electrocatalytic hydrogen evolution catalyst. The method comprises the following steps: basic magnesium carbonate, soot, zinc chloride, nickel nitrate, cobalt nitrate and urea are used as raw materials, and a high-temperature calcination method, a hydrothermal method and a partial reduction method are adopted to obtain the defective nickel cobaltate/porous carbon composite material, so that a preparation method is provided for improving the electrocatalytic hydrogen evolution performance of the existing nickel cobaltate.)

1. The preparation method of the defective nickel cobaltate/porous carbon is completed according to the following steps:

(1) dissolving basic magnesium carbonate, soot and zinc chloride in 10 ml of deionized water, stirring for 1 hour, drying, placing the mixture in a tube furnace, and adding N₂Heating at high temperature under the protection condition, washing the obtained product with water and hydrochloric acid, and drying to obtain soot-derived carbon;

(2) cobalt nitrate, nickel nitrate and urea were dissolved in 10 ml of deionized water, stirred for 1 hour, and 0.2 g of the soot-derived carbon obtained in step (1) was added to the above solution, and stirred for 15 minutes. Then, the mixture was transferred to a 50 ml autoclave for hydrothermal reaction. Washing with deionized water and ethanol after the reaction is finished, drying, and calcining the sample in a muffle furnace to obtain nickel cobaltate/porous carbon;

(3) respectively placing the nickel cobaltate/porous carbon and sodium hypophosphite obtained in the step (2) into two porcelain boats of a tube furnace, wherein the sodium hypophosphite is positioned at the upstream and is positioned at N₂Calcining under the protection condition to obtain the defective nickel cobaltate/porous carbon.

2. The method for preparing the defective nickel cobaltate/porous carbon according to claim 1, wherein the defective nickel cobaltate/porous carbon is prepared by the following steps: in the step (1), the mass of the alkali type magnesium carbonate is 0.1-0.8 g, the mass of the soot is 0.1-0.8 g, the mass of the zinc chloride is 0.1-0.8 g, the reaction temperature of the tubular furnace is 450-700 ℃, the reaction time is 1-4 hours, the drying temperature is 50-80 ℃, and the drying time is 6-24 hours.

3. The method for preparing the defective nickel cobaltate/porous carbon according to claim 1, wherein the defective nickel cobaltate/porous carbon is prepared by the following steps: in the step (2), the mass of the cobalt nitrate is 0.1-0.4 g, the mass of the nickel nitrate is 0.1-0.4 g, the mass of the urea is 0.1-0.8 g, the hydrothermal reaction temperature of the high-pressure kettle is 140 ℃, the reaction time is 12-16 hours, the drying temperature is 50-80 ℃, the drying time is 6-24 hours, the calcining temperature is 250-400 ℃, and the calcining time is 1-4 hours.

4. The method for preparing the defective nickel cobaltate/porous carbon according to claim 1, wherein the defective nickel cobaltate/porous carbon is prepared by the following steps: in the step (3), the mass ratio of nickel cobaltate/porous carbon to sodium hypophosphite is 1: 5, the calcining temperature of the tubular furnace is 250-700 ℃, the calcining time is 1-5 hours, the drying temperature is 50-80 ℃, and the drying time is 6-24 hours.

Technical Field

The invention relates to a preparation method of defective nickel cobaltate/porous carbon.

Background

Hydrogen is an ideal energy carrier and can be produced by the Hydrogen Evolution Reaction (HER) of an electrocatalyst in water electrolysis, which provides a sustainable method of hydrogen production in rich energy conversion technologies. Currently, platinum-based materials are considered to be the most effective electrocatalytic hydrogen evolution catalysts, but their wide application is limited by the high cost. Therefore, the development of an efficient and abundant electrocatalytic hydrogen evolution catalyst is currently the focus of research.

Nickel cobaltate has more excellent electrochemical activity than monometallic nickel/cobalt oxide, but its conductivity and electrochemical active sites still need to be improved. The nickel cobaltate grows on the porous carbon in situ, and the conductivity of the nickel cobaltate is improved and the electrochemical active sites are enriched by manufacturing oxygen defects, so that the electro-catalytic hydrogen evolution capability of the nickel cobaltate is improved, and the method has important research significance for solving the problem of energy shortage.

Disclosure of Invention

The invention aims to overcome the problems of poor conductivity and few reactive active sites of nickel cobaltate and provides a simple, novel and high-yield preparation method.

The preparation method of the defect nickel cobaltate/porous carbon is completed according to the following steps:

(1) dissolving basic magnesium carbonate, soot and zinc chloride in 10 ml of deionized water, stirring for 1 hour, drying, placing the mixture in a tube furnace, and adding N₂Heating at high temperature under the protection condition, washing the obtained product with water and hydrochloric acid, and drying to obtain soot-derived carbon;

(2) cobalt nitrate, nickel nitrate and urea were dissolved in 10 ml of deionized water, stirred for 1 hour, and 0.2 g of the soot-derived carbon obtained in step (1) was added to the above solution, and stirred for 15 minutes. Then, the mixture was transferred to a 50 ml autoclave for hydrothermal reaction. Washing with deionized water and ethanol after the reaction is finished, drying, and calcining the sample in a muffle furnace to obtain nickel cobaltate/porous carbon;

(3) respectively placing the nickel cobaltate/porous carbon and sodium hypophosphite obtained in the step (2) into two porcelain boats of a tube furnace, wherein the sodium hypophosphite is positioned at the upstream and is positioned at N₂Calcining under the protection condition to obtain the defective nickel cobaltate/porous carbon.

In the step (1), the mass of the alkali type magnesium carbonate is 0.1-0.8 g, the mass of the soot is 0.1-0.8 g, the mass of the zinc chloride is 0.1-0.8 g, the reaction temperature of the tubular furnace is 450-700 ℃, the reaction time is 1-4 hours, the drying temperature is 50-80 ℃, and the drying time is 6-24 hours;

in the step (2), the mass of the cobalt nitrate is 0.1-0.4 g, the mass of the nickel nitrate is 0.1-0.4 g, the mass of the urea is 0.1-0.8 g, the hydrothermal reaction temperature of the high-pressure kettle is 100-140 ℃, the reaction time is 12-16 hours, the drying temperature is 50-80 ℃, the drying time is 6-24 hours, the calcining temperature is 250-400 ℃, and the calcining time is 1-4 hours;

in the step (3), the mass ratio of nickel cobaltate/porous carbon to sodium hypophosphite is 1: 5, the calcining temperature of the tubular furnace is 250-700 ℃, the calcining time is 1-5 hours, the drying temperature is 50-80 ℃, and the drying time is 6-24 hours.

Compared with the prior art, the invention has the beneficial effects that: the defect type nickel cobaltate/porous carbon electro-catalysis hydrogen evolution composite material is prepared, the composite material with complete structure and large specific surface area can be prepared only in a short time in the preparation process, in addition, the synthesis of the material does not need complex equipment, and the prepared composite material has excellent electro-catalysis hydrogen evolution performance.

Drawings

FIG. 1 is an XRD spectrum of example 1 deficient nickel cobaltate/porous carbon.

FIG. 2 is a scanning electron microscope image of example 1 deficient nickel cobaltate/porous carbon.

FIG. 3 is a TEM image of example 1 deficient nickel cobaltate/porous carbon.

FIG. 4 is a linear cyclic voltammogram of the deficient nickel cobaltate/porous carbon of example 1.

FIG. 5 is the electrochemical impedance plot of the deficient nickel cobaltate/porous carbon of example 1.

Detailed Description

The technical solution of the present invention is not limited to the specific embodiments listed below, which are only used for illustrating the present invention and are not limited to the technical solutions described in the embodiments of the present invention. It will be appreciated by those skilled in the art that the present invention may be modified or substituted equally as well to achieve the same technical result. So long as the use requirements are met, the invention is within the protection scope.

The preparation method of the defective nickel cobaltate/porous carbon of the embodiment is completed according to the following steps:

(1)0.2 g basic magnesium carbonate, 0.2 g soot and 0.2 g zinc chlorideDissolved in 10 ml of deionized water, stirred for 1 hour, dried and the mixture was placed in a tube furnace under N₂Heating at high temperature under the protection condition, washing the obtained product with water and hydrochloric acid, and drying to obtain soot-derived carbon;

(2) 0.2 g of cobalt nitrate, 0.1 g of nickel nitrate and 0.1 g of urea were dissolved in 10 ml of deionized water, stirred for 1 hour, and 0.2 g of the soot-derived carbon obtained in step (1) was added to the above solution, and stirred for 15 minutes. Then, the mixture was transferred to a 50 ml autoclave for hydrothermal reaction. Held at 120 degrees celsius for 16 hours and cooled to room temperature. Washing with deionized water and ethanol after the reaction is finished, drying at 60 ℃ for 12 hours, and calcining the sample in a muffle furnace at 300 ℃ for 2 hours to obtain nickel cobaltate/porous carbon;

(3) respectively placing 0.2 g of nickel cobaltate/porous carbon and 1 g of sodium hypophosphite obtained in the step (2) into two porcelain boats of a tube furnace, wherein the sodium hypophosphite is positioned at the upstream and is positioned at N₂And (3) heating to 250 ℃ at the heating rate of 5 ℃ per second under the protection condition, and calcining for 1 hour to obtain the defective nickel cobaltate/porous carbon.

The invention is further explained by combining the drawings and the embodiments:

FIG. 1 is an XRD spectrum of example 1 deficient nickel cobaltate/porous carbon. The diffraction peaks at 31.0, 38.5, 44.7, 56.2, 59.3 and 65.8 deg. correspond to the (220), (311), (400), (422), (511) and (440) crystal planes (JCPDS No.20-0781), demonstrating nickel cobaltate in the product and 27.5 deg. diffraction peaks demonstrating carbon in the product.

FIG. 2 is a scanning electron microscope image of example 1 deficient nickel cobaltate/porous carbon. Linear nickel cobaltate is grown on the porous carbon surface.

FIG. 3 is a TEM image of example 1 deficient nickel cobaltate/porous carbon. Linear nickel cobaltate is grown on the porous carbon surface.

FIG. 4 is a linear cyclic voltammogram of the deficient nickel cobaltate/porous carbon of example 1. At 10mA/cm²The over potential of the defect type nickel cobaltate/porous carbon is close to that of pure platinum and is far less than that of defect-free nickel cobaltate/porous carbon, defect type nickel cobaltate and defect-free type nickel cobaltateAnd a soot-derived carbon control group, and the target product is proved to have excellent electro-catalytic hydrogen evolution performance.

FIG. 5 is the electrochemical impedance plot of the deficient nickel cobaltate/porous carbon of example 1. The radius of the arc of the curve in the high-frequency area is the electron transfer resistance, and the slope of the straight line in the low-frequency area is the transmission transfer rate of the electrolyte ions, so that the electron transfer resistance of the defective nickel cobaltate is lower than that of the control group, and the transmission transfer rate of the electrolyte ions is higher than that of the control group.