CN113046780A

CN113046780A - NiCoP/C two-dimensional carbon material, preparation method thereof and application thereof in electrochemistry

Info

Publication number: CN113046780A
Application number: CN202110246775.7A
Authority: CN
Inventors: 胡霖; 费正皓; 杨琉涵; 罗瑞; 巫先坤; 刘总堂
Original assignee: Yancheng Teachers University
Current assignee: Yancheng Teachers University
Priority date: 2021-03-05
Filing date: 2021-03-05
Publication date: 2021-06-29

Abstract

The invention discloses a preparation method of a NiCoP/C two-dimensional carbon material, which comprises the following steps: mixing a cobalt source, a nickel source, a cross-linking agent and sodium lignosulfonate to obtain a mixture, and carbonizing powder of the mixture under the protection of inert gas to obtain the catalyst. According to the method, sodium lignosulphonate is used as a carbon source, phytic acid is used as a catalyst, and cobalt and nickel are used as transition metals to prepare the C, P co-doped layered two-dimensional carbon material. The synthetic NiCoP/C two-dimensional carbon material is simple and green in preparation method, and has good stability and good conductivity. The prepared NiCoP/C two-dimensional carbon material has a layered space structure, effectively improves the specific surface area and the performance of the material, and improves the electrocatalytic activity.

Description

NiCoP/C two-dimensional carbon material, preparation method thereof and application thereof in electrochemistry

Technical Field

The invention belongs to the field of biomass charcoal materials, and particularly relates to a NiCoP/C two-dimensional carbon material, a preparation method thereof and application thereof in electrochemistry.

Background

With the rapid development of world economy, the population is continuously increased, the excessive consumption of non-renewable fossil fuel resources such as coal, petroleum and the like directly causes environmental pollution and energy shortage, the sustainable development of modern society faces serious crisis and other problems, in recent years, novel carbon materials such as graphene, carbon nanotubes and the like have attracted wide attention in the field of energy storage due to unique physicochemical properties, and the novel carbon materials have high conductivity, excellent chemical stability, adjustable porosity, high specific surface area and abundant electroactive sites. However, such carbon materials rely on fossil fuel-based precursors, use energy-intensive synthesis processes, are environmentally hazardous and are costly. Biomass, which is a plant or plant-based substance derived from nature and synthesized by photosynthesis of carbon dioxide and water, is another precursor of carbon materials, which is one of the most abundant renewable resources on earth, unlike fossil fuels. Biomass has sustainability, renewability, and wide availability.

The carbon content of the sodium lignosulfonate is high, and the structure of the sodium lignosulfonate contains a large amount of sulfonic acid groups, alcoholic hydroxyl groups, phenolic hydroxyl groups and a small amount of carbonyl groups, so that a crosslinking reaction is easier to occur and the sodium lignosulfonate can be used as a carbon source of a carbon-based material. In order to improve the electrochemical performance, Phytic Acid (PA) is used as a biological organic acid by means of a catalyst, is widely present in plant tissues of beans, grains and oilseeds, has a six-membered ring phosphate group structure in PA molecules, has strong reactivity, can be effectively chelated with metal ions, and is a cross-linking agent with high acting force. Therefore, the PA is complexed with the cobalt chloride and the nickel chloride and is combined with the sodium lignosulfonate, and due to the sustainability of the precursor and the simple method for preparing the phosphorus-doped carbon catalyst, the reaction condition is moderate, so that the catalyst is a green catalyst system, and the electrochemical efficiency is effectively improved.

Disclosure of Invention

Aiming at the problems of the prior art, the invention provides a NiCoP/C two-dimensional carbon material, a preparation method and an application thereof in electrochemistry, wherein the NiCoP/C two-dimensional carbon material has good electrocatalytic activity in the aspect of electrocatalytic hydrogen evolution.

The purpose of the invention can be achieved by adopting the following technical scheme:

a preparation method of a NiCoP/C two-dimensional carbon material comprises the following steps:

mixing a cobalt source, a nickel source, a cross-linking agent and sodium lignosulfonate to obtain a mixture, and carbonizing powder of the mixture under the protection of inert gas to obtain the catalyst.

Preferably, the cross-linking agent is Phytic Acid (PA).

Preferably, the mixture is obtained by mixing the cobalt source, the nickel source and the carbon source in a solution and then removing the solvent.

Preferably, the solvent is water; preferably distilled water.

Preferably, the method for removing the solvent is evaporation to dryness.

Preferably, the mixing is stirring mixing; magnetic stirring is preferably employed. More preferably, the rotation speed of the magnetic stirring is 850 r/min.

Preferably, the molar ratio of cobalt to nickel to carbon is 1-10: 10-50.

Preferably, the cobalt source is cobalt chloride, and the nickel source is nickel chloride.

Preferably, the carbonization temperature is 500-800 ℃; more preferably 600 deg.c.

Preferably, the inert gas is nitrogen.

Under preferred conditions, the present invention comprises the steps of:

(1) adding CoCl₂·6H₂O、NiCl₂·6H₂Dissolving O and PA in distilled water, and fully stirring;

(2) dissolving sodium lignosulfonate in distilled water, and fully stirring;

(3) fully mixing the solutions obtained in the steps (1) and (2), adding a rotor, placing on a magnetic stirrer, stirring at 850r/min for 1.5 hours, and then stirring at 85 ℃ and 900r/min for 6 hours until the water is evaporated to dryness;

(4) taking out the rotor, placing the obtained precipitate in a vacuum drying oven, heating to 80 ℃, and drying for 12 hours to obtain a mixture;

(5) grinding the mixture in an agate mortar in an 8 shape, washing with deionized water, and drying to obtain powder of the mixture;

(6) putting the dried powder of the mixture into a tube furnace, and introducing N₂Carbonizing at 500-800 ℃ to obtain the product;

the invention also provides the NiCoP/C two-dimensional carbon material prepared by the preparation method.

The invention also provides an application of the NiCoP/C two-dimensional carbon material prepared by the preparation method in electrochemistry.

The invention has the beneficial effects that:

the preparation method of the NiCoP/C two-dimensional carbon material prepared by the invention is simple and green, and the synthesized two-dimensional carbon material has good stability and good hydrogen evolution activity. The NiCoP/C two-dimensional carbon material has a layered space structure, has a larger specific surface area, improves the number of active sites, and effectively improves the performance of the material.

Drawings

FIG. 1 is a scanning electron micrograph of NiCoP/C prepared in example 1 of the present invention at 600 ℃.

FIG. 2 is a transmission electron micrograph of NiCoP/C prepared in example 1 of the present invention at 600 ℃.

FIG. 3 shows NiCoP/C obtained in examples 1, 2, 3 and 4 of the present invention at 600 deg.C, 500 deg.C, 700 deg.C, 1mol/L H deg.C, and 800 deg.C₂SO₄LSV diagram of (a).

FIG. 4 shows NiCoP/C prepared in examples 1, 5 and 6 of the present invention at 600 ℃ and NiP/C, CoP/C at 1mol/L H₂SO₄LSV diagram of (a).

FIG. 5 shows NiCoP/C prepared in example 1 of the present invention at 600 ℃ C. at 1mol/L H₂SO₄LSV diagram of (a).

FIG. 6 is a Mott-Schottky test analysis chart of NiP/C, CoP/C prepared in examples 5 and 6.

Detailed Description

In order to make the technical solutions of the present invention more clear and definite for those skilled in the art, the present invention is further described in detail below with reference to the following embodiments and the accompanying drawings, but the implementation methods of the present invention are not limited thereto.

Example 1

10ml of distilled water was weighed into a beaker, and CoCl was weighed₂·6H₂O in a beaker, and adding NiCl₂·6H₂O and 1.3710gPA, fully stirring, weighing sodium lignosulfonate in 10ml of distilled water, fully stirring, fully mixing the two samples, wherein the molar ratio of cobalt to nickel to carbon in the sodium lignosulfonate is 1:1:50, stirring at normal temperature of 850r/min for 1.5 hours, then stirring at 85 ℃ and 900r/min for 6 hours until the moisture is evaporated to dryness, placing the samples in a vacuum drying box, heating to 80 ℃ for drying for 12 hours, washing with deionized water for drying, carbonizing at 600 ℃, and grinding after the firing is finished to obtain a sample labeled NiCoP/C600 ℃;

example 2

This example differs from example 1 only in that: the molar ratio of cobalt to nickel to carbon in sodium lignosulfonate was 10:1:10, the carbonization temperature was 500 ℃, and the obtained sample was designated as NiCoP/C500 ℃.

Example 3

This example differs from example 1 only in that: the molar ratio of cobalt to nickel to carbon in sodium lignosulfonate was 1:10:50, the carbonization temperature was 700 ℃, and the obtained sample was designated as NiCoP/C700 ℃.

Example 4

This example differs from example 1 only in that: the molar ratio of cobalt to nickel to carbon in sodium lignosulfonate was 10:10:10, the carbonization temperature was 500 ℃, and the obtained sample was designated as NiCoP/C800 ℃.

Example 5 (comparative example)

10ml of distilled water was measured and poured into a beaker, and 0.4067g of NiCl was additionally weighed₂·6H₂Adding 1.1710g of PA into the beaker, and fully stirring; weighing 1.0286g of sodium lignosulfonate in 10ml of distilled water, and fully stirring; the two are mixed evenly and stirred, and the mixture is carbonized at 600 ℃ after being dried and washed, and the obtained sample is marked as NiP/C.

Example 6 (comparative example)

10ml of distilled water was weighed into a beaker, and 0.4067g of CoCl was weighed₂·6H₂Adding 1.1710g of PA into the beaker, and fully stirring; weighing 1.0286g of sodium lignosulfonate in 10ml of distilled water, and fully stirring; the two are mixed evenly and stirred, and the mixture is carbonized at 600 ℃ after being dried and washed, and the obtained sample is marked as CoP/C.

Example 7

The electrocatalysis test method comprises the following steps: weighing 5mg of the prepared NiCoP/C two-dimensional carbon material, pouring the NiCoP/C two-dimensional carbon material into a small test tube containing deionized water, carrying out ultrasonic treatment until the NiCoP/C two-dimensional carbon material is in an ink shape, titrating a sample on an electrode by using a liquid transfer gun, drying the sample by using an infrared lamp until the sample is in a solid particle shape, and titrating a dispersing agent Nafion the dried sample to prevent the particles from falling off in electrolyte. Taking a saturated calomel electrode as a reference electrode, a platinum wire as a counter electrode, and a working electrode arranged at a position containing 1mol/L H₂SO₄Performing electrochemical test in the solution electrolytic cell, measuring CV 5 circles before each test, starting to test LSV curve after standing for 900s, and obtaining the curve with 10mA cm by electrochemical test^-2The overpotential can reach 146 mV.

The following tests were carried out on the materials obtained in examples 1 to 6, the results of which are shown in the figure:

FIG. 1 is a scanning electron micrograph of NiCoP/C600 ℃ material prepared in example 1, wherein a is a scanning electron micrograph of NiCoP/C600 ℃ material at 1 μm, and b is a scanning electron micrograph of NiCoP/C600 ℃ material at 2 μm. As can be seen from the graph (a), the NiCoP/C600 ℃ material has a sheet-shaped two-dimensional structure and is uniformly distributed.

FIG. 2 is a transmission electron micrograph of NiCoP/C at 600 ℃ obtained in example 1, wherein a is a transmission electron micrograph of NiCoP/C at 600 ℃ at 100. mu.m, and b is a transmission electron micrograph of NiCoP/C at 600 ℃ at 200. mu.m. It can be seen from the figure that the metallic nickel and the metallic cobalt of the NiCoP/C600 ℃ material are uniformly dispersed, and the whole structure is in a flake shape.

FIG. 3 shows NiCoP/C600 ℃, NiCoP/C500 ℃, NiCoP/C700 ℃, NiCoP/C800 ℃ and Pt 1mol/L H for the samples obtained in examples 1, 2, 3 and 4₂SO₄LSV curve in solution. As can be seen from the figure, the better the hydrogen evolution performance of the material with increasing carbonization temperature, the best at 600 ℃, the better the HER activity of NiCoP/C material, which requires lower overpotential (146mv) to generate 10mA cm in acidic medium^-2Current density value of (a).

FIG. 4 shows NiCoP/C prepared in examples 1, 5 and 6 at 600 ℃, NiP/C, CoP/C and Pt at 1mol/L H₂SO₄LSV curve in solution. As can be seen from the figure, the compounds of nickel and cobalt alone generally perform when combined to produce Co₃The hydrogen evolution performance at P is closer to that of Pt.

FIG. 5 shows NiCoP/C600 ℃ and Pt 1mol/L H for NiCoP prepared in example 1₂SO₄LSV curve in solution. It can be seen from the figure that the material performance obtained is optimal at a carbonization temperature of 600 ℃, NiCoP/C material has better HER activity, and it needs lower over-potential (145mv) to generate 10mA cm in acidic medium^-2Current density value of (a).

FIG. 6 is a Mott-Schottky test analysis of NiP/C, CoP/C prepared in examples 5 and 6. To further confirm the assumption that electrons were transferred under different measurement methods, a mott-schottky analysis was performed and fig. 6 shows an inverted V-shape, indicating that the panel charging potential (UF) was 0.69 and 1.23V for NiP/C, CoP/C, respectively.

The above description is only for the purpose of illustrating the present invention and is not intended to limit the scope of the present invention, and any person skilled in the art can substitute or change the technical solution of the present invention and its conception within the scope of the present invention.

Claims

1. A preparation method of a NiCoP/C two-dimensional carbon material is characterized by comprising the following steps:

2. The method according to claim 1, wherein the crosslinking agent is phytic acid.

3. The method according to claim 1, wherein the mixture is obtained by mixing the cobalt source, the nickel source and the carbon source in a solution and then removing the solvent.

4. The production method according to claim 3, wherein the solvent is water; preferably distilled water.

5. The method of claim 3, wherein the solvent is removed by evaporation.

6. The production method according to claim 3, wherein the mixing is stirring mixing; preferably, magnetic stirring is adopted, and more preferably, the rotating speed of the magnetic stirring is 850 r/min.

7. The method according to claim 1, wherein the molar ratio of cobalt to nickel to carbon is 1 to 10:10 to 50.

8. The method according to claim 1, wherein the carbonization temperature is 500 to 800 ℃; preferably 600 deg.c.

9. A NiCoP/C two-dimensional carbon material produced by the production method according to any one of claims 1 to 8.

10. The use of NiCoP/C two-dimensional carbon material prepared by the method of any one of claims 1-8 in electrochemistry.