Preparation method of rare earth element doped nickel-based selenide nano-material and application of rare earth element doped nickel-based selenide nano-material in electro-catalysis water complete hydrolysis reaction

Abstract

The invention discloses a preparation method of a rare earth element doped nickel-based selenide nano-material and application of the rare earth element doped nickel-based selenide nano-material in electro-catalysis water full-hydrolysis reaction. According to the method, nickel salt, cerium salt, selenium dioxide and potassium chloride are prepared into electrolyte, and the electrolyte is subjected to electro-deposition on a foamed nickel substrate to obtain Ce-doped Ni0.85Se nanoparticles growing on foamed nickel. The crystal structure and electron distribution of Ni0.85Se are optimized by doping trace rare earth element cerium, so that the HER and OER performances of the Ni0.85Se are greatly improved. The prepared catalyst is self-supporting closely-packed nanoparticles, the formed amorphous structure is easy to expose more active sites, the catalyst has good electrocatalytic hydrogen evolution and oxygen evolution performance under alkaline conditions, the overpotential in electrocatalysis of nickel-based selenide is greatly reduced, and the electrocatalytic performance of nickel-based selenide is improved. And excellent electro-catalytic activity is shown in electro-catalytic water full hydrolysis. And the self-supporting electrode is not easy to fall off due to generation of bubbles in the reaction process, so that the working stability of the catalyst is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electrocatalytic nanomaterial preparation, and particularly relates to a preparation method of a rare earth element doped nickel-based selenide nanomaterial and application thereof in electrocatalytic water overall decomposition reaction. BACKGROUND

[0002] At present, developing green new energy has become an urgent demand to realize the goal of building an environmentally friendly society, and hydrogen energy, as a kind of efficient and clean energy, is an important target of developing new energy in China. Electrochemical water decomposition has considerable development potential in the direction of hydrogen energy acquisition due to its high efficiency and environmental protection. At present, electrochemical water decomposition technology still mainly adopts noble metal catalysts (such as Pt, RuO2, IrO2, etc.), however, the high price and scarce resource reserves limit its application in industrial production, and developing non-noble metal catalysts for electrochemical water decomposition to replace noble metals is an effective way to solve this problem.

[0003] Nickel, iron, cobalt, molybdenum and other transition metal compounds are reported to have certain electrocatalytic water decomposition performance, but often only have good catalytic performance in the half-reaction of water decomposition, namely oxygen evolution (OER) or hydrogen evolution (HER), and the catalytic performance for water overall decomposition is not satisfactory. SUMMARY

[0004] The application provides a preparation method of a rare earth element doped nickel-based selenide nanomaterial and application thereof in electrocatalytic water overall decomposition reaction. The traditional selenization process is often accompanied by pollution and complicated operation, and the application adopts a more environmentally friendly, simple and easy-to-produce electro-deposition synthesis method, which is fast and more likely to form amorphous structure components, thereby exposing more active sites.

[0005] The preparation method of the rare earth element doped nickel-based selenide nanomaterial comprises the following steps: (1) ultrasonic treatment of foamed nickel in hydrochloric acid and acetone in sequence, and then washing with ionized water and ethanol alternately and drying; (2) dissolving nickel chloride, cerium nitrate, selenium dioxide and potassium chloride in deionized water to obtain an electro-deposition solution; (3) placing the foamed nickel treated in step (1) as a working electrode in the electro-deposition solution to perform electro-deposition, so as to obtain the rare earth element doped nickel-based selenide nanomaterial, and then washing with ionized water and ethanol alternately and drying.

[0006] The concentration of nickel chloride in the electro-deposition solution is 0.01-0.8 mol / L, the concentration of cerium nitrate is 0.002-0.02 mol / L, the concentration of selenium dioxide is 0.2-5 mmol / L, and the concentration of potassium chloride is 0.1-1 mmol / L.

[0007] The electrodeposition process adopts a three-electrode system, an Ag / AgCl electrode as a reference electrode, a platinum wire electrode as a counter electrode, and a constant potential method to set the potential to -1.1 V.

[0008] The rare earth element doped nickel selenide nanomaterial prepared above is applied to an electrocatalytic water hydrogen evolution reaction as a cathode catalyst.

[0009] The rare earth element doped nickel selenide nanomaterial prepared above is applied to an electrocatalytic water oxygen evolution reaction as an anode catalyst.

[0010] The rare earth element doped nickel selenide nanomaterial prepared above is applied to an electrocatalytic water hydrogen evolution reaction as a cathode catalyst.

[0011] The present application prepares an electrolyte by mixing a nickel salt, a cerium salt, selenium dioxide and potassium chloride, and then performs electrodeposition on a nickel foam substrate to obtain a Ce-doped Ni 0.85 Se nanoparticle grown on the nickel foam. The crystal structure and electronic distribution of the Ni 0.85 Se are optimized by doping a trace amount of the rare earth element cerium, so that the HER and OER performance is greatly improved. The prepared catalyst is a self-supporting tightly packed nanoparticle with low crystallinity, and the amorphous structure formed is easy to expose more active sites. The catalyst has good electrocatalytic hydrogen evolution and oxygen evolution performance under alkaline conditions, greatly reduces the overpotential in the electrocatalytic nickel selenide, and exhibits excellent electrocatalytic activity in the electrocatalytic water splitting. The self-supporting electrode is not easy to fall off due to the generation of bubbles during the reaction, and the stability of the catalyst work is improved. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 The scanning electron microscope image of the 5% Ce-Ni 0.85 Se / NF electrocatalytic material prepared in Example 1 of the present application, the left is a low magnification image, and the right is a high magnification image.

[0013] Figure 2 The scanning electron microscope image of the 5% Ce-Ni 0.85 Se and Ni 0.85 Se powder.

[0014] Figure 3 The scanning electron microscope image of the 5% Ce-Ni 0.85 Se / NF and Ni 0.85 The linear sweep curve diagram of the HER of the 5% Ce-Ni

[0015] Figure 4 The scanning electron microscope image of the 5% Ce-Ni 0.85 Se / NF electrocatalytic material prepared in Example 1 of the present application, the left is a low magnification image, and the right is a high magnification image.-2 The HER stability curve under the current density.

[0016] Figure 5 Ce-doped Ni prepared in different proportions according to Examples 1-4 and Comparative Example 1 of this invention 0.85 Se / NF and Ni 0.85 Linear scan curve of OER for Se / NF electrocatalytic material.

[0017] Figure 6 The 5% Ce-Ni prepared in Example 1 of this invention 0.85 Se / NF electrocatalytic materials at 10 mA cm⁻¹ -2 The OER stability curve under the current density.

[0018] Figure 7 The 5% Ce-Ni prepared in Example 1 of this invention 0.85 Linear scan curves of water total hydrolysis of Se / NF electrocatalytic materials.

[0019] Figure 8 The 5% Ce-Ni prepared in Example 1 of this invention 0.85 Stability curves of the Se / NF electrocatalyst material at a working voltage of 1.56V for total water hydrolysis. Detailed Implementation

[0020] To illustrate the present invention more clearly, the following embodiments are provided for further description, but these do not limit the scope of protection of the present invention. Example 1

[0021] This embodiment includes 5% Ce-Ni 0.85 The preparation of Se rare earth element-doped transition metal selenide nickel-based electrocatalysts for water splitting and their electrocatalytic water splitting performance testing in 1 M KOH environment are as follows: (1) Pretreatment of nickel foam (NF) Cut the nickel foam into small pieces of 1 cm × 2 cm, sonicate in 3 M HCl for 15 minutes to remove the oxide layer, then sonicate in acetone for 15 minutes. After removing it, clean the NF surface with deionized water and ethanol in sequence, and dry it in a vacuum drying oven at 60°C.

[0022] (2) Electrodeposition preparation of 5% Ce-Ni 0.85 Se / NF electrode Weigh out 5 mmol NiCl2·6H2O (1.188 g), 1.25 mmol SeO2 (0.1386 g), 6.25 mmol KCl (0.4656 g), and 0.25 mmol Ce(NO3)3·6H2O (0.1085 g), and dissolve them in 50 ml of deionized water to form NiCl2·6H2O. 2+ (0.1 M) and Ce 3+ A mixed solution of (0.005 M) was used as the sedimentation solution.

[0023] Electrodeposition was performed in a three-electrode single-cell system using a CHI660 electrochemical workstation with a potentiostatic method. An Ag / AgCl electrode was used as the reference electrode, and 5% Ce-Ni alloy was added. 0.85 Se / NF was used as the working electrode, and a platinum wire electrode as the counter electrode. The voltage was set to -1.1 V, and the deposition time was 300 s. After electrodeposition, the obtained 5% Ce-Ni was washed alternately with water and ethanol. 0.85 Se / NF was vacuum dried overnight at 60°C.

[0024] (3) Application of electrocatalytic water splitting The electrolyte used was 1M KOH solution. 5% Ce-Ni0.85Se / NF was used as the working electrode, a platinum wire electrode as the counter electrode, and an Ag / AgCl electrode as the reference electrode. The overpotentials and stability of the hydrogen evolution reaction and oxygen evolution reaction, as well as the total water hydrolysis potential and stability, were tested. Example 2

[0025] This embodiment includes 2% Ce-Ni 0.85 The preparation of Se rare earth element-doped transition metal selenide nickel-based electrocatalysts for water splitting and their electrocatalytic water splitting performance testing in 1 M KOH environment are as follows: (1) Pretreatment of nickel foam (NF) As in step (1) of Example 1.

[0026] (2) Electrodeposition preparation of 2% Ce-Ni 0.85 Se / NF electrode Weigh out 5 mmol NiCl2·6H2O (1.188 g), 1.25 mmol SeO2 (0.1386 g), 6.25 mmol KCl (0.4656 g), and 0.1 mmol Ce(NO3)3·6H2O (0.0434 g), and dissolve them in 50 ml of deionized water to form NiCl2·6H2O. 2+ (0.1 M) and Ce 3+ A mixed solution of (0.002 M) was used as the sedimentation solution.

[0027] Electrodeposition was performed in a three-electrode single-cell system using a CHI660 electrochemical workstation with a potentiostatic method. An Ag / AgCl electrode was used as the reference electrode, and 2% Ce-Ni alloy was added. 0.85 Se / NF was used as the working electrode, and a platinum wire electrode as the counter electrode. The voltage was set to -1.1 V, and the deposition time was 300 s. After electrodeposition, the obtained 2% Ce-Ni was washed alternately with water and ethanol. 0.85 Se / NF was vacuum dried overnight at 60°C.

[0028] (3) Application of electrocatalytic water splitting The electrolyte used is a 1M KOH solution with 2% Ce-Ni 0.85 Using Se / NF as the working electrode, a platinum wire electrode as the counter electrode, and an Ag / AgCl electrode as the reference electrode, the overpotentials of the hydrogen evolution reaction and the oxygen evolution reaction were measured. Example 3

[0029] This embodiment includes 10% Ce-Ni 0.85 The preparation of Se rare earth element-doped transition metal selenide nickel-based electrocatalysts for water splitting and their electrocatalytic water splitting performance testing in 1 M KOH environment are as follows: (1) Pretreatment of nickel foam (NF) As in step (1) of Example 1.

[0030] (2) Electrodeposition preparation of 10% Ce-Ni 0.85 Se / NF electrode Weigh out 5 mmol NiCl2·6H2O (1.188 g), 1.25 mmol SeO2 (0.1386 g), 6.25 mmol KCl (0.4656 g), and 0.5 mmol Ce(NO3)3·6H2O (0.217 g), and dissolve them in 50 ml of deionized water to form NiCl2·6H2O. 2+ (0.1 M) and Ce 3+ A mixed solution of (0.01 M) was used as the sedimentation solution.

[0031] (3) Application of electrocatalytic water splitting The electrolyte used is a 1M KOH solution with 10% Ce-Ni 0.85 Using Se / NF as the working electrode, a platinum wire electrode as the counter electrode, and an Ag / AgCl electrode as the reference electrode, the overpotentials of the hydrogen evolution reaction and the oxygen evolution reaction were measured.

[0032] Electrodeposition was performed in a three-electrode single-cell system using a CHI660 electrochemical workstation with a potentiostatic method. An Ag / AgCl electrode was used as the reference electrode, and 10% Ce-Ni alloy was employed. 0.85Se / NF was used as the working electrode, and a platinum wire electrode as the counter electrode. The voltage was set to -1.1 V, and the deposition time was 300 s. After electrodeposition, the obtained 10% Ce-Ni was washed alternately with water and ethanol. 0.85 Se / NF was vacuum dried overnight at 60°C. Example 4

[0033] This embodiment includes 20% Ce-Ni 0.85 The preparation of Se rare earth element-doped transition metal selenide nickel-based electrocatalysts for water splitting and their electrocatalytic water splitting performance testing in 1 M KOH environment are as follows: (1) Pretreatment of nickel foam (NF) As in step (1) of Example 1.

[0034] (2) Electrodeposition preparation of 20% Ce-Ni 0.85 Se / NF electrode Weigh out 5 mmol NiCl2·6H2O (1.188 g), 1.25 mmol SeO2 (0.1386 g), 6.25 mmol KCl (0.4656 g), and 1 mmol Ce(NO3)3·6H2O (0.434 g), and dissolve them in 50 ml of deionized water to form NiCl2·6H2O. 2+ (0.1 M) and Ce 3 + A mixed solution of (0.02 M) was used as the sedimentation solution.

[0035] Electrodeposition was performed in a three-electrode single-cell system using a CHI660 electrochemical workstation with a potentiostatic method. An Ag / AgCl electrode was used as the reference electrode, and 20% Ce-Ni alloy was employed. 0.85 Se / NF was used as the working electrode, and a platinum wire electrode as the counter electrode. The voltage was set to -1.1 V, and the deposition time was 300 s. After electrodeposition, the resulting 20% ​​Ce-Ni was washed alternately with water and ethanol. 0.85 Se / NF was vacuum dried overnight at 60°C.

[0036] (3) Application of electrocatalytic water splitting The electrolyte used is a 1M KOH solution with 20% Ce-Ni 0.85 Using Se / NF as the working electrode, a platinum wire electrode as the counter electrode, and an Ag / AgCl electrode as the reference electrode, the overpotentials of the hydrogen evolution reaction and the oxygen evolution reaction were measured. Comparative Example 1

[0037] This embodiment includes Ni 0.85The preparation of Se transition metal selenide nickel-based water electrolysis catalysts and their electrocatalytic water splitting performance testing in a 1 MKOH environment were carried out as follows: (1) Pretreatment of nickel foam (NF) As in step (1) of Example 1.

[0038] (2) Electrodeposition preparation of Ni 0.85 Se / NF electrode Ni was electrodeposited in one step on NF. 0.85 Se, weigh out 5 mmol NiCl2·6H2O (1.188 g), 1.25 mmol SeO2 (0.1386 g), and 6.25 mmol KCl (0.4656 g), dissolve in 50 ml deionized water to form 0.1 M Ni. 2+ The solution serves as the electrolyte.

[0039] Electrodeposition was performed in a three-electrode single-cell system using a CHI660 electrochemical workstation with a potentiostatic method. An Ag / AgCl electrode was used as the reference electrode, and Ni... 0.85 Se / NF was used as the working electrode, and a platinum wire electrode as the counter electrode. The voltage was set to -1.1 V, and the deposition time was 300 s. After electrodeposition, the resulting Ni was washed alternately with water and ethanol. 0.85 Se / NF was vacuum dried overnight at 60°C.

[0040] (3) Application of electrocatalytic water splitting The electrolyte used was a 1M KOH solution. Ni0.85Se / NF was used as the working electrode, a platinum wire electrode as the counter electrode, and an Ag / AgCl electrode as the reference electrode. The overpotentials of the hydrogen evolution reaction and the oxygen evolution reaction were tested.

[0041] Figure 1 The image shows a 5% Ce-Ni0.85Se nanoparticle layer grown on the surface of nickel foam in Example 1. The nanoparticles are uniformly stacked on the surface of nickel foam and appear as tightly bound clusters of nanoparticles.

[0042] Figure 2 The figures shown are X-ray diffraction patterns of Examples 1-4 and Comparative Example 1. The diffraction peaks obtained are all similar to those of Ni. 0.85 Corresponding to the standard PDF card for Se, the addition of Ce did not create new characteristic peaks, proving that Ce was introduced in the form of lattice doping. The diffraction peaks weaken with increasing Ce doping ratio, indicating that Ce doping reduces the Ni content. 0.85 The degree of crystallinity of Se.

[0043] Figure 3 , Figure 5The figures show the linear sweep voltammetry curves for HER and OER in Examples 1-4 and Comparative Example 1, respectively. The 5% Ce-Ni0.85Se / NF prepared in Example 1 exhibited the best HER and OER catalytic performance, achieving a current density of 10 mA / cm² during the HER process. -2 Only an overpotential of 128 mV is required, while the overpotential of Ni0.85Se / NF prepared in Comparative Example 1 is 256 mV; however, during the OER process, the current density reaches 10 mA cm⁻¹. -2 The required overpotential is only 209 mV, exceeding that of many reported OER electrocatalysts. In contrast, the overpotential of Ni0.85Se / NF prepared in Comparative Example 1 was 282 mV. This demonstrates that the doping of rare earth element cerium significantly improves the electrocatalytic performance of nickel-based selenides.

[0044] from Figure 4 and Figure 6 The stability test results show that, regardless of whether it is the hydrogen evolution or oxygen evolution reaction, the 5% Ce-Ni0.85Se / NF electrolyte can be maintained at 10 mA cm⁻¹ in 1M KOH electrolyte. -2 It can work stably for more than 20 hours, demonstrating good stability.

[0045] Figure 7 The linear sweep voltammetry curve of a water electrolyzer composed of 5% Ce-Ni0.85Se / NF prepared in Example 1, used as both cathode and anode, is shown. At an electrode voltage of 1.56 V, a 10 mA cm⁻¹ was generated. -2 Its current density is higher than that of many reported water electrolytic catalysts, and its water electrolysis catalytic performance is superior. Figure 8 As shown, the 5%Ce-Ni0.85Se / NF water hydrolysis system can operate stably for more than 20 hours at a voltage of 1.56V, which proves the stability of the water hydrolysis operation of this invention.

Claims

1. A method for preparing rare earth element-doped nickel-based selenide nanomaterials, characterized in that, The specific steps of the preparation method are as follows: (1) The nickel foam was ultrasonically treated in hydrochloric acid and acetone in sequence, and then washed with deionized water and ethanol alternately and dried. (2) Dissolve nickel chloride, cerium nitrate, selenium dioxide, and potassium chloride in deionized water to use as electrodeposition solution; (3) The foamed nickel treated in step (1) is placed in the electrodeposition solution for electrodeposition to obtain rare earth element doped nickel selenide nanomaterials. The nanomaterials are washed with deionized water and ethanol alternately and then dried.

2. The preparation method according to claim 1, characterized in that, The electrodeposition solution contains nickel chloride at a concentration of 0.01-0.8 mol / L, cerium nitrate at a concentration of 0.002-0.02 mol / L, selenium dioxide at a concentration of 0.2-5 mmol / L, and potassium chloride at a concentration of 0.1-1 mmol / L.

3. The preparation method according to claim 1, characterized in that, The electrodeposition process employs a three-electrode system, with an Ag / AgCl electrode as the reference electrode and a platinum wire electrode as the counter electrode, and the potential is set to -1.1V using a constant potential method.

4. The application of rare earth element-doped nickel-based selenide nanomaterials prepared by the method according to any one of claims 1-3 as cathode catalysts in electrocatalytic hydrogen evolution reaction.

5. The application of rare earth element-doped nickel-based selenide nanomaterials prepared by the method according to any one of claims 1-3 as an anode catalyst in the electrocatalytic oxygen evolution reaction.

6. The application of rare earth element-doped nickel-based selenide nanomaterials prepared by the method according to any one of claims 1-3 as dual electrodes in electrocatalytic water hydrolysis reaction.

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