阅读说明：本技术 一种Co2P/CuP2/NF析氢析氧电催化剂制备方法 (Co2P/CuP2Preparation method of/NF hydrogen evolution and oxygen evolution electrocatalyst ) 是由 杨秀林 王丽霞 于 2021-08-11 设计创作，主要内容包括：本发明涉及电催化水分解技术领域,具体为一种Co-(2)P/CuP-(2)/NF析氢析氧电催化剂制备方法,通过低温水热、恒电位电沉积以及低温磷化处理的方法得到的Co-(2)P/CuP-(2)/NF复合材料,所述水热是将CuO生长在泡沫镍上,获得Cu基前驱体；在CuO的表面恒电位电沉积Co物种,获得Cu-Co复合材料前驱体,在氮气的气氛下进行低温磷化处理。本发明制备方法简单,通过以泡沫镍为基底进行低温水热、恒电位电沉积以及低温磷化处理得到Co-(2)P/CuP-(2)/NF复合材料,在碱性的条件下具有优异的电催化析氢和析氧性能,另外还可将其应用于锌水电池,且使用寿命较长。(The invention relates to the technical field of electrocatalytic water decomposition, in particular to Co 2 P/CuP 2 Preparation method of/NF hydrogen and oxygen evolution electrocatalyst, Co obtained by low-temperature hydrothermal, constant potential electrodeposition and low-temperature phosphating treatment 2 P/CuP 2 The method comprises the following steps of/NF composite material, wherein CuO grows on foam nickel in the hydrothermal process to obtain a Cu-based precursor; and (3) electrodepositing Co species on the surface of the CuO at constant potential to obtain a Cu-Co composite material precursor, and performing low-temperature phosphating treatment in the atmosphere of nitrogen. The preparation method is simple, and Co is obtained by performing low-temperature hydrothermal, constant-potential electrodeposition and low-temperature phosphating treatment by taking foamed nickel as a substrate 2 P/CuP 2 /NF compositeThe material has excellent electro-catalytic hydrogen evolution and oxygen evolution performances under the alkaline condition, and can be applied to a zinc water battery with long service life.)

1. Co₂P/CuP₂The preparation method of the/NF hydrogen and oxygen evolution electrocatalyst is characterized by comprising the following steps: co obtained by low-temperature hydrothermal, constant potential electrodeposition and low-temperature phosphating treatment₂P/CuP₂a/NF composite; wherein, a CuO precursor grows by taking foamed nickel as a substrate through the low-temperature hydrothermal method; performing constant potential electrodeposition of Co species on the surface of the CuO precursor to obtain a Cu-Co precursor; carrying out low-temperature phosphating treatment under the atmosphere of nitrogen to obtain the Co₂P/CuP₂a/NF composite material.

2. The method of claim 1, wherein: the preparation of the CuO precursor is that copper chloride dihydrate is ultrasonically dissolved in deionized water to obtain a mixed solution, ammonia water is added to adjust the pH value of the solution, and nickel foam is placed in the mixed solution to carry out the low-temperature hydrothermal reaction to obtain the CuO precursor.

3. The method of claim 2, wherein: the constant potential electrodeposition takes the CuO precursor as a working electrode and a cobalt nitrate solution as an electrolyte, and electrodeposition is carried out at a constant potential of-1.1V for 3-7 min.

4. The production method according to claim 3, characterized in that: the amount of the copper chloride dihydrate is 0.2-1.0 mmol.

5. The method of claim 4, wherein: the temperature of the low-temperature hydrothermal reaction is 80 ℃, and the reaction time is 2 hours.

6. The method of claim 5, wherein: the temperature of the low-temperature phosphating treatment is 350 ℃, and the time is 2 hours.

Technical Field

The invention belongs to the field of electrocatalytic total moisture decomposition, and particularly relates to Co₂P/CuP₂A preparation method of a NF hydrogen and oxygen evolution electrocatalyst.

Background

When fossil fuels are exhausted, people must look for new energy sources to replace carbon-based energy sources. As a clean and high-efficientAnd a sustainable energy carrier, hydrogen being a promising energy alternative to traditional fossil fuels. Water splitting is a better method of generating hydrogen gas due to its sustainability and environmental friendliness. Water splitting can be achieved by using electricity or light, and compared with electrocatalytic water splitting, it has higher conversion efficiency and higher yield of hydrogen, and is a more practical method. However, water splitting actually requires a very large voltage, 1.23V above the theoretical minimum cell potential, which clearly hinders the slow kinetics of the water electrolysis involving Hydrogen Evolution Reactions (HER) and Oxygen Evolution Reactions (OER). Thus, acceleration H₂And O₂Is the key to developing a highly efficient catalyst and minimizing the associated overpotential. At present, the zinc water battery has few applications in practice, so that it is necessary to explore and develop a high-performance and low-cost electrocatalyst to replace the traditional noble metal-based catalyst, and the prepared catalyst is applied to the zinc water battery.

Disclosure of Invention

The invention aims to provide Co₂P/CuP₂The preparation method of the NF hydrogen and oxygen evolution electrocatalyst solves the problems in the background technology.

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

co₂P/CuP₂The preparation method of the/NF hydrogen and oxygen evolution electrocatalyst comprises the steps of low-temperature hydrothermal, constant potential electrodeposition and low-temperature phosphating₂P/CuP₂a/NF composite; wherein, a CuO precursor grows by taking foamed nickel as a substrate through the low-temperature hydrothermal method; performing constant potential electrodeposition of Co species on the surface of the CuO precursor to obtain a Cu-Co precursor; carrying out low-temperature phosphating treatment under the atmosphere of nitrogen to obtain the Co₂P/CuP₂a/NF composite material.

Further, the preparation of the CuO precursor is that copper chloride dihydrate is ultrasonically dissolved in deionized water to obtain a mixed solution, ammonia water is added to adjust the pH value of the solution, and nickel foam is placed in the mixed solution to perform the low-temperature hydrothermal reaction to obtain the CuO precursor.

Further, the constant potential electrodeposition takes the CuO precursor as a working electrode, takes a cobalt nitrate solution as an electrolyte, and performs electrodeposition at a constant potential of-1.1V for 3-7 min.

Further, the amount of the copper chloride dihydrate is 0.2-1.0 mmol.

Further, the temperature of the low-temperature hydrothermal reaction is 80 ℃, and the reaction time is 2 hours.

Further, the temperature of the low-temperature phosphating treatment is 350 ℃ and the time is 2 hours.

Compared with the prior art, the invention has the beneficial effects that:

the preparation method is simple, and Co is obtained by performing low-temperature hydrothermal, constant-potential electrodeposition and low-temperature phosphating on foamed nickel serving as a substrate₂P/CuP₂the/NF composite material has excellent electro-catalysis hydrogen evolution and oxygen evolution performances under an alkaline condition, can be applied to a zinc water battery, and has long service life.

Drawings

FIG. 1 is a linear scan plot of CuO/NF-x mmol prepared in example 1;

FIG. 2 is Co prepared in example 4₂P/CuP₂Linear scanning curve of/NF-x min composite material;

FIG. 3 is CuO/NF prepared in example 1 and CuP prepared in example 2₂/NF and Co prepared in example 3₂X-ray powder diffractogram of P/NF;

FIG. 4(a) is an X-ray powder diffraction pattern of example 4; FIG. 4(b) is a view under a scanning electron microscope; FIGS. 4(c) and (d) are transmission electron micrographs; FIG. 4(e) is a selected area electron diffraction pattern; FIG. 4(f) is element Mapping;

FIG. 5 is Co prepared in example 4₂P/CuP₂/NF composite, CuP prepared in example 2₂/NF and Co prepared in example 3₂An X-ray photoelectron spectrum of P/NF;

FIG. 6 is a linear scanning curve of electrocatalytic oxygen evolution under alkaline conditions in examples 2-4;

FIG. 7 is a linear scanning curve of electrocatalytic hydrogen evolution under alkaline conditions in examples 2-4;

FIG. 8 is Co prepared in example 4₂P/CuP₂Stability of the/NF composite in 1.0M KOH;

FIG. 9 is Co prepared in example 4₂P/CuP₂Testing of the/NF composite in 1.0M KOH, FIG. 9(a) is a two electrode test; FIG. 9(b) is a two-electrode stability test;

FIG. 10 is Co prepared in example 4₂P/CuP₂The application of the/NF composite material in a zinc water battery is shown in fig. 10(a) as open-circuit voltage, fig. 10(b) as power density, fig. 10(c) as an illuminated LED lamp and fig. 10(d) as a stability test of the zinc water battery.

Detailed Description

The technical solution in the embodiment of the present invention will be described below with reference to fig. 1 to 10 in the embodiment of the present invention.

Firstly, preparing commercial Pt/C and RuO₂As electrode samples, for comparison with examples of the present invention: weighing 2 mg of commercial Pt/C, dissolving the Pt/C in 200 muL of deionized water, 200 muL of absolute ethyl alcohol and 10 muL of Nafion solution, ultrasonically dissolving for 30 minutes, and then dropping Pt/C slurry subjected to uniform ultrasonic treatment in 1 cm²Dried at room temperature for use.

Preparation of RuO in the same manner as described above₂Electrode sample, except commercial Pt/C was changed to RuO₂And (4) finishing.

Second, example 1: preparation of CuO/NF material

Step (1), treating foamed nickel: cutting foamed nickel into 3 × 1.5 cm²Size. Then ultrasonic washing is respectively carried out in 0.5 mol/L sulfuric acid solution, deionized water and ethanol for 10 minutes, and the ultrasonic washing is carried out for three times and naturally aired for standby.

Preparing a copper chloride dihydrate solution: 0.6 mmol (0.2, 0.4, 0.8, 1.0 mmol) of copper chloride dihydrate is weighed and dissolved in 15 mL of deionized water, the solution is subjected to ultrasonic treatment for 10 minutes to obtain a copper chloride solution, and then 750 uL of ammonia water is added to the solution to be subjected to ultrasonic treatment for 10 minutes.

And (3) carrying out low-temperature hydrothermal reaction: and (3) placing the foamed nickel washed in the step (1) into a small glass bottle containing 20 mL of the solution prepared in the step (2), and keeping the temperature in an oven for 2 hours at the temperature of 80 ℃. After natural cooling, the foamed nickel is rinsed with a large amount of water and then dried at room temperature for use.

Third, example 2: preparation of CuP₂/NF Material

Step (1), treating foamed nickel: cutting foamed nickel into 3 × 1.5 cm²Size. Then ultrasonic washing is respectively carried out in 0.5 mol/L sulfuric acid solution, deionized water and ethanol for 10 minutes, and the ultrasonic washing is carried out for three times and naturally aired for standby.

Preparing a copper chloride dihydrate solution: weighing 0.8 mmol of copper chloride dihydrate, dissolving the copper chloride dihydrate in 15 mL of deionized water, performing ultrasonic treatment for 10 minutes to obtain a copper chloride solution, adding 750 uL of ammonia water, performing ultrasonic treatment for 10 minutes, and adjusting the pH value of the solution.

And (3) carrying out low-temperature hydrothermal reaction: and (3) placing the foamed nickel washed in the step (1) into a small glass bottle containing 20 mL of the solution prepared in the step (2), and keeping the temperature in an oven for 2 hours at the temperature of 80 ℃. After natural cooling, the foamed nickel is rinsed with a large amount of water and then dried at room temperature for use.

And (4) low-temperature phosphating treatment: putting the foamed nickel of the CuO/NF precursor in the step (3) into the bottom of a quartz tube, weighing 1 g of sodium hypophosphite and putting the sodium hypophosphite into the opening of the quartz tube, and then heating the quartz tube at the temperature of 5 ℃ for min in a nitrogen atmosphere (20 sccm)^-1) Calcining at 350 deg.C for 2 hr, naturally cooling to room temperature, taking out, washing with deionized water, and air drying at room temperature to obtain CuP₂a/NF material.

Fourth, example 3: preparation of Co₂P/NF material

Step (1), treating foamed nickel: cutting foamed nickel into 1 × 1.5 cm²Size. Then ultrasonic washing is respectively carried out in 0.5 mol/L sulfuric acid solution, deionized water and ethanol for 10 minutes, and the ultrasonic washing is carried out for three times and naturally aired for standby.

Preparing a cobalt nitrate solution: 0.29 g of cobalt nitrate hexahydrate is weighed and dissolved in 25 mL of deionized water, and the solution is subjected to ultrasonic treatment for 10 minutes to obtain a cobalt nitrate solution.

Step (3), constant potential electrodeposition: and (3) in a three-electrode system, taking foamed nickel as a working electrode, a platinum sheet as a counter electrode, a saturated calomel electrode as a reference electrode and electrolyte as the cobalt nitrate solution prepared in the step (2), and performing electrodeposition for 5 min under the constant potential of-1.1V. After natural cooling, the foamed nickel is rinsed by deionized water and then dried at room temperature for later use.

And (4) phosphating: placing the Co precursor subjected to constant potential electrodeposition in the step (3) in the bottom of a quartz tube, weighing 1 g of sodium hypophosphite and placing the sodium hypophosphite in the opening of the quartz tube, and then heating the mixture in a nitrogen atmosphere (20 sccm) (5 ℃ for min)^-1) Calcining for 2 hours at 350 ℃, naturally cooling to room temperature, taking out, washing with a large amount of deionized water, and airing at room temperature to prepare the Co₂P/NF material.

Fifth, example 4: preparation of Co₂P/CuP₂/NF Material

Step (1), treating foamed nickel: cutting foamed nickel into 3 × 1.5 cm²Size. Then ultrasonic washing is respectively carried out in 0.5 mol/L sulfuric acid solution, deionized water and ethanol for 10 minutes, and the ultrasonic washing is carried out for three times and naturally aired for standby.

Preparing a copper chloride dihydrate solution: weighing 0.8 mmol of copper chloride dihydrate, dissolving the copper chloride dihydrate in 15 mL of deionized water, performing ultrasonic treatment for 10 minutes to obtain a copper chloride solution, adding 750 uL of ammonia water, performing ultrasonic treatment for 10 minutes, and adjusting the pH value of the solution.

And (3) carrying out low-temperature hydrothermal reaction: and (3) placing the foamed nickel washed in the step (1) into a small glass bottle containing 20 mL of the solution prepared in the step (2), and keeping the temperature in an oven for 2 hours at the temperature of 80 ℃. After natural cooling, the foamed nickel is rinsed with a large amount of water and then dried at room temperature for use.

Step (4), constant potential electrodeposition: and (3) in a three-electrode system, taking CuO/NF as a working electrode, a platinum sheet as a counter electrode, a saturated calomel electrode as a reference electrode and electrolyte as a cobalt nitrate solution prepared in the step (2), and electrodepositing for 5 min (and 3 min, 4 min, 6 min and 7 min) under the constant potential of-1.1V. After natural cooling, the foamed nickel is rinsed by deionized water and then dried at room temperature for later use.

And (5) low-temperature phosphating treatment: putting the Cu-Co/NF precursor in the step (4) in a quartz tubeIn the bottom, 1 g of sodium hypophosphite was weighed out and placed at the mouth of a quartz tube, and then heated (5 ℃ C. for min) under a nitrogen atmosphere (20 sccm)^-1) Calcining for 2 hours at 350 ℃, naturally cooling to room temperature, taking out, washing with a large amount of deionized water, and airing at room temperature to prepare the Co₂P/CuP₂a/NF material.

Sixth, electrochemical test

Electrochemical testing: both the electrocatalytic hydrogen evolution and oxygen evolution tests were carried out on an electrochemical workstation (Bio-Logic VMP3, France) using a three-electrode system. CuO/NF-x mmol and Co prepared in examples 1-4₂P/NF、CuP₂/NF、Co₂P/CuP₂the/NF-xmin composite material is used as a working electrode, the graphite plate is used as a counter electrode, the saturated calomel electrode is used as a reference electrode, 1.0M KOH solution is used as electrolyte, the test temperature is 25 ℃, and the scanning speed is 10 mV/s. The electrode potential was obtained by applying a saturated calomel electrode, and a Reversible Hydrogen Electrode (RHE) and impedance compensation correction were performed. All potentials herein were obtained according to the following nernst equation:

E_RHE = E_SCE+0.241+0.059 pH-iR

whereiniFor the current tested, R is the solution impedance. The electrolyzed water test was carried out on an electrochemical workstation (Bio-Logic VMP3, France) using a two-electrode system.

Seventh, test results

FIG. 1 shows that the CuO/NF produced in the sample of example 1 is best for electrochemical hydrogen and oxygen evolution when the amount of copper chloride dihydrate added is 0.6 mmol.

FIG. 2 shows that Co prepared in the sample of example 4₂P/CuP₂/NF, the best performance for electrochemical hydrogen and oxygen evolution when the electrodeposition time is 5 min.

FIG. 3 shows that CuO/NF produced in the sample of example 1 and CuP produced in the sample of example 2₂NF and Co prepared in example 3 samples₂The X-ray powder diffraction patterns of P/NF correspond.

FIG. 4(a) shows Co in example 4₂P/CuP₂X-ray of/NFA line powder diffraction pattern; FIG. 4(b) is a scanning electron micrograph of example 4 showing the nanoplatelets morphology; as shown in FIG. 4(c) and FIG. 4(d), transmission electron micrographs are shown; FIG. 4(e) and FIG. 4(f) are the selected area electron diffraction and element uniformity distribution diagrams, respectively.

FIG. 5 shows a reaction system at Co₂P/CuP₂The electron transfer effect exists in the/NF composite material. Wherein Co is shown in FIG. 5(a)₂P/CuP₂Co-P binding energy relative to Co in NF composite material₂P/NF produced a negative bias, Co in FIG. 5(b)₂P/CuP₂Cu in/NF composite material²⁺Relative to the binding energy of CuP₂the/NF also produces a negative bias. And Co₂P/CuP₂Metal P vs. Co in NF₂P/NF and CuP₂both,/NF produced positive offsets. Thus demonstrating Co₂P/CuP₂The electron synergistic effect exists in the/NF composite material, and the conductivity and the intrinsic catalytic activity of the catalyst are improved through the electron synergistic effect.

FIG. 6(a) shows Co prepared according to the present invention₂P/CuP₂Electrocatalytic oxygen evolution linear scan polarization curves in 1.0M KOH for the/NF composite and the control. When the current density is 10 mA/cm²Has an overpotential of 220 mV, next to RuO₂/NF, superior to other controls. FIG. 6(b) shows Co prepared by the present invention₂P/CuP₂Tafel slope, Co in 1.0M KOH for/NF composite and control₂P/CuP₂Tafel slope of 68 mV dec for/NF^-1Indicating that it has faster reaction kinetics.

FIG. 7 shows Co prepared by the present invention₂P/CuP₂Electrocatalytic hydrogen evolution linear scan polarization curves in 1.0M KOH for the/NF composite and the control. When the current density is 100 mA cm^-2The overpotential of (2) is 195 mV, which is superior to other comparison samples. FIG. 7(b) shows Co prepared according to the present invention₂P/CuP₂the/NF composite material and the comparative sample have Tafel slope, Co corresponding to hydrogen evolution reaction in 1.0M KOH₂P/CuP₂Tafel slope of 61 mV dec for/NF^-1The kinetic mechanism of the reaction is indicated to be a Volmer-Heyrovsky mechanism.

FIG. 8 shows Co prepared by the present invention₂P/CuP₂the/NF composite material was subjected to stability testing in a three-electrode system. FIG. 8(a) at 10 mA cm^-2The performance can be stabilized for 200 hours with little degradation. FIG. 8(b) at-10 mA cm^-2The performance was stable for 200 hours and hardly deteriorated, showing that Co of the present invention₂P/CuP₂the/NF composite material has better stability.

FIG. 9 shows Co prepared by the present invention₂P/CuP₂Linear scan polarization curves of the/NF composite were tested in two electrodes of 1.0M KOH. When the current density reaches 500 mA cm^-2The cell voltage is only 1.77V, and the current density reaches 1000 mA cm^-2The cell voltage is only 2.38V, which shows the Co of the invention₂P/CuP₂the/NF composite material has excellent total hydrolysis performance and is due to Pt/C and RuO₂Two electrodes are formed. FIG. 9(b) shows the two-electrode test at 100 mA cm^-2The performance was stable for 160 hours with almost no deterioration, and the Co of the present invention was also shown₂P/CuP₂the/NF composite material has better stability.

FIG. 10 shows Co prepared by the present invention₂P/CuP₂The application of the/NF composite material in a zinc water battery. FIG. 10(a) shows the open circuit voltage test, which is about 0.98V, and FIG. 10(b) shows the power density test, which is close to Pt/C. FIG. 10(c) shows two of the polymers consisting of Co₂P/CuP₂The batteries of/NF are connected in series to light an LED lamp. FIG. 10(d) is a stability test of a zinc water battery, which can be stabilized substantially for 120 hours with little deterioration of performance, and also shows that Co of the present invention₂P/CuP₂the/NF composite material has better stability.

In comparative examples 1, 2, 3 and 4, example 1 only performed a low-temperature hydrothermal reaction to produce a CuO precursor, CuO/NF. Example 2 is a low-temperature phosphating treatment based on example 1 to obtain CuP₂and/NF. Example 3 constant potential electrodeposition was directly performed on the nickel foam to obtain a Co precursor, and then the Co precursor was subjected to low temperature phosphating to obtain Co₂P/NF. And example 4 is that of example 1The obtained CuO is subjected to constant potential electrodeposition and then low-temperature phosphating treatment to obtain Co₂P/CuP₂/NF。

The above description is only for the purpose of illustrating the preferred embodiments of the present invention, and it is to be understood that the invention is not limited thereto, but may be modified within the scope of the appended claims.