CN115627485A

CN115627485A - Anode for hydrogen production from alkaline water and preparation method thereof

Info

Publication number: CN115627485A
Application number: CN202110797849.6A
Authority: CN
Inventors: 高珊; 李爽; 陆崖青; 景慧英; 张兀
Original assignee: Bluestar Beijing Chemical Machinery Co Ltd
Current assignee: Bluestar Beijing Chemical Machinery Co Ltd
Priority date: 2021-07-14
Filing date: 2021-07-14
Publication date: 2023-01-20

Abstract

An anode for preparing hydrogen from alkaline water and its preparing process, which comprises preparing soluble salt of at least one noble metal element selected from Ru, ir, rh, pd or Pt; preparing at least one soluble salt of transition metal elements, wherein the transition metal elements are lanthanum La, iron Fe, cobalt Co, nickel Ni or copper Cu; dissolving at least one soluble salt of a noble metal element and at least one soluble salt of a transition metal element in water to prepare a coating liquid stock solution for the surface layer of the anode substrate, wherein the total metal concentration in the aqueous solution is 200-250 g/L, and the molar percentage of the noble metal element is 20-35% and the molar percentage of the transition metal element is 65-80% according to the metal components, thereby obtaining the coating liquid stock solution for the surface layer of the anode substrate. The anode for producing hydrogen from alkaline water and the preparation method thereof aim to provide the anode for producing hydrogen from alkaline water, which has low oxygen evolution overpotential and long service life under high current density.

Description

Anode for hydrogen production from alkaline water and preparation method thereof

Technical Field

The invention relates to an anode for hydrogen production by alkaline water and a preparation method thereof.

Background

With the continuous enhancement of carbon neutralization strength of carbon emission reduction, the requirements on clean energy and renewable energy are increasing day by day, and hydrogen energy becomes an important component of an energy system. The water electrolysis hydrogen production technology has a plurality of advantages, on one hand, raw materials are easy to obtain, the equipment is simple, and the operation and management are convenient; on the other hand, the production process of hydrogen production by electrolyzing water has no pollution, and the produced hydrogen is recognized in a plurality of hydrogen production methods and has high purity and low impurity content and is suitable for various hydrogen using places.

The anode for producing hydrogen from alkaline water is completely different from the anode for chlor-alkali, and the anode for producing hydrogen from alkaline water belongs to an oxygen evolution anode and the anode for producing chlorine from chlorine evolution from the reaction mechanism; from the operating conditions, the former operates in alkaline water, and the latter operates in brine; in terms of substrate selection, the former generally employs a nickel substrate, and the latter generally employs a titanium substrate.

At present, the mature oxygen evolution anode applied to the water electrolysis hydrogen production device comprises the following components:

(1) Nickel has good corrosion resistance in an alkaline medium, the oxygen evolution overpotential of nickel in metal elements is relatively low, but the oxygen evolution overpotential is still higher compared with an electrode with a catalytic layer, and the nickel is widely used as an alkaline water electrolysis anode because the price is relatively cheap;

(2) Noble metal oxides, which have good catalytic activity for hydrogen evolution and oxygen evolution, but are expensive;

(3)ABO ₃ perovskite oxide and AB ₂ O ₄ The spinel type oxide has the advantages of low oxygen evolution overpotential, alkali corrosion resistance, low cost and the like, and is considered to be the anode catalytic material with the most research prospect at present.

Under alkaline conditions, water electrolysis hydrogen production anode reaction: 4OH ^- -4e ^- ＝2H ₂ O+O ₂ ↑

At present, the operation conditions of the alkaline water hydrogen production electrolytic cell are generally 70-90 ℃ and the current density is 2KA/m ² -4KA/m ² The electrolyte is 30-32% NaOH or KOH, operating at high current density, i.e. at 4KA/m, as the technology matures ² The operation under the current density is a future development trend, so that an electrode which has low oxygen evolution overpotential and long service life under high current density is needed, and the prior anode for producing hydrogen from alkaline water generally has no such performance.

Disclosure of Invention

The invention aims to provide a high-current-density oxygen evolution low-overpotential low-service-life catalyst which can be used at 6KA/m ² And the anode for producing hydrogen by alkaline water and the preparation method thereof, which operate under high current density.

The anode for producing hydrogen from alkaline water is prepared by the following steps:

A. preparing soluble salt of at least one precious metal element, wherein the precious metal element is ruthenium Ru, iridium Ir, rhodium Rh, palladium Pd or platinum Pt; preparing soluble salt of at least one transition metal element, wherein the transition metal element is lanthanum La, iron Fe, cobalt Co, nickel Ni or copper Cu;

B. dissolving at least one soluble salt of a noble metal element and at least one soluble salt of a transition metal element in water to prepare a coating liquid stock solution for the surface layer of the anode substrate, wherein the total metal concentration in the aqueous solution is 200-250 g/L, and the molar percentage of the noble metal element is 20-35% and the molar percentage of the transition metal element is 65-80% according to metal components to obtain the coating liquid stock solution for the surface layer of the anode substrate;

dissolving at least one soluble salt of a noble metal element and at least one soluble salt of a transition metal element in water to prepare a coating liquid stock solution for a first intermediate layer, wherein the total metal concentration in the aqueous solution is 200-250 g/L, and the molar percentage of the noble metal element is 5-9% and the molar percentage of the transition metal element is 91-95% based on metal components, so as to obtain the coating liquid stock solution for the first intermediate layer;

dissolving at least one soluble salt of a noble metal element and at least one soluble salt of a transition metal element in water to prepare a coating liquid stock solution for the second intermediate layer, wherein the total metal concentration in the aqueous solution is 200-250 g/L, and the molar percentage of the noble metal element is 10-14% and the molar percentage of the transition metal element is 86-90% based on metal components, so as to obtain the coating liquid stock solution for the second intermediate layer;

dissolving at least one soluble salt of a noble metal element and at least one soluble salt of a transition metal element in water to prepare a coating liquid stock solution for the third intermediate layer, wherein the total metal concentration in the aqueous solution is 200 g/L-250 g/L, and the molar percentage of the noble metal element is 15% -19% and the molar percentage of the transition metal element is 81% -85% based on metal components to obtain the coating liquid stock solution for the third intermediate layer;

C. adding a graphene aqueous solution into the coating liquid stock solution for the surface layer of the anode substrate obtained in the step B, wherein the graphene proportion is 0.1-3 g/L, and then stirring the salt solution by using an ultrasonic mixer to uniformly mix the salt solution to obtain an active coating liquid for the surface layer of the anode substrate;

adding a graphene aqueous solution into the coating liquid stock solution for the first intermediate layer obtained in the step B, wherein the ratio of graphene is 0.1-3 g/L, and then stirring the salt solution by using an ultrasonic mixer to uniformly mix the salt solution to obtain an active coating liquid for the first intermediate layer;

adding a graphene aqueous solution into the coating liquid stock solution for the second intermediate layer obtained in the step B, wherein the graphene proportion is 0.1-3 g/L, and then stirring the salt solution by using an ultrasonic mixer to uniformly mix the salt solution to obtain an active coating liquid for the second intermediate layer;

adding a graphene aqueous solution into the coating liquid stock solution for the third intermediate layer obtained in the step B, wherein the ratio of graphene in the graphene aqueous solution is 0.1-3 g/L, and then stirring the salt solution by using an ultrasonic mixer to uniformly mix the salt solution to obtain an active coating liquid for the third intermediate layer;

D. sanding and pickling a metal matrix of the anode for hydrogen production from alkaline water to roughen the surface of the metal matrix, wherein the metal matrix contains nickel;

E. d, carrying out heat treatment on the metal matrix obtained in the step D in an oxygen-containing atmosphere, wherein the heat treatment temperature is 350-550 ℃, and the time is 20-60 minutes, so that the surface of the metal matrix is oxidized, and the metal matrix containing nickel oxide is obtained;

F. coating the coating liquid stock solution for the first intermediate layer obtained in the step C on the metal substrate obtained in the step E, and then carrying out heat treatment on the metal substrate coated with the coating liquid stock solution for the first intermediate layer in an oxygen-containing atmosphere, wherein the heat treatment condition is 350-400 ℃, and the heat treatment condition is keptHeating to 400-550 deg.C within 5 min for 5-10 min, maintaining for 10-50 min, cooling to room temperature, and forming an active coating on the outer surface of the metal substrate, wherein the single-layer coating amount of the active coating is 4.2-6.3 g/m ² ；

Coating the coating liquid stock solution for the first intermediate layer obtained in the step C again, then carrying out heat treatment on the metal substrate coated with the coating liquid stock solution for the first intermediate layer in an oxygen-containing atmosphere, wherein the heat treatment condition is 350-400 ℃, keeping the temperature for 5-10 minutes, raising the temperature of the furnace to 400-550 ℃ within 5 minutes, keeping the temperature for 10-50 minutes, rapidly cooling the metal substrate to room temperature after the heat treatment is finished, and generating an active coating on the outer surface of the metal substrate again, wherein the single-layer coating amount of the active coating is 4.2g/m ² —6.3g/m ² ；

G. Coating the coating liquid stock solution for the second intermediate layer obtained in the step C on the metal substrate obtained in the step F, then carrying out heat treatment on the metal substrate coated with the coating liquid stock solution for the second intermediate layer in an oxygen-containing atmosphere, wherein the heat treatment condition is 350-400 ℃, keeping the temperature for 5-10 minutes, raising the temperature of the furnace to 400-550 ℃ within 5 minutes, keeping the temperature for 10-50 minutes, rapidly cooling the metal substrate to room temperature after the heat treatment is finished, and generating an active coating on the outer surface of the metal substrate, wherein the single-layer coating amount of the active coating is 4.2g/m ² —6.3g/m ² ；

Coating the coating liquid stock solution for the second intermediate layer obtained in the step C again, then carrying out heat treatment on the metal substrate coated with the coating liquid stock solution for the second intermediate layer in an oxygen-containing atmosphere, wherein the heat treatment condition is 350-400 ℃, keeping the temperature for 5-10 minutes, raising the temperature of the furnace to 400-550 ℃ within 5 minutes, keeping the temperature for 10-50 minutes, rapidly cooling the metal substrate to room temperature after the heat treatment is finished, and generating an active coating on the outer surface of the metal substrate again, wherein the single-layer coating amount of the active coating is 4.2g/m ² —6.3g/m ² ；

H. Coating the coating liquid stock solution for the third intermediate layer obtained in the step C on the metal substrate obtained in the step G, and then carrying out heat treatment on the metal substrate coated with the coating liquid stock solution for the third intermediate layer in an oxygen-containing atmosphere, wherein the heat treatment condition is 350-400 ℃, and the heat preservation is carried out for 5-10 minutes and 5 minutesHeating the furnace to 400-550 deg.C, maintaining for 10-50 min, cooling to room temperature, and forming an active coating on the outer surface of the metal substrate, wherein the single coating amount of the active coating is 4.2g/m ² —6.3g/m ² ；

Coating the coating liquid stock solution for the third intermediate layer obtained in the step C again, then carrying out heat treatment on the metal substrate coated with the coating liquid stock solution for the third intermediate layer in an oxygen-containing atmosphere, wherein the heat treatment condition is 350-400 ℃, keeping the temperature for 5-10 minutes, raising the temperature of the furnace to 400-550 ℃ within 5 minutes, keeping the temperature for 10-50 minutes, rapidly cooling the metal substrate to room temperature after the heat treatment is finished, and generating an active coating on the outer surface of the metal substrate again, wherein the single-layer coating amount of the active coating is 4.2g/m ² —6.3g/m ² ；

I. Coating the surface layer of the anode base material obtained in the step C on the metal matrix treated in the step H by using the active coating solution, then carrying out heat treatment on the metal matrix coated with the coating solution in an oxygen-containing atmosphere, wherein the heat treatment condition is 350-400 ℃, keeping the temperature for 5-10 minutes, raising the temperature of the furnace to 400-550 ℃ within 5 minutes, keeping the temperature for 10-50 minutes, rapidly cooling the metal matrix to room temperature after the heat treatment is finished, and generating an active coating on the outer surface of the metal matrix, wherein the single-layer coating amount of the active coating is 4.2g/m ² —6.3g/m ² ；

J. Repeating the step I again, and repeating the steps in a circulating way until the total coating amount of the active coating on the surface of the metal substrate is more than or equal to 50g/m ² ；

K. And D, carrying out firing heat treatment on the metal matrix obtained in the step J, wherein the firing heat treatment temperature is 350-500 ℃, the firing heat treatment time is 50-100 minutes, and rapidly cooling the metal matrix to room temperature after the heat treatment is finished to obtain the anode for hydrogen production by alkaline water.

Preferably, in the step B, a coating liquid stock solution for the surface layer of the anode substrate is prepared by dissolving soluble salts of two or more noble metal elements and soluble salts of two or more transition metal elements in water, so that the total metal concentration in the aqueous solution is 210g/L to 240g/L, wherein the molar percentage of the noble metal elements is 23% to 33% and the molar percentage of the transition metal elements is 67% to 77% based on the metal components, and the coating liquid stock solution for the surface layer of the anode substrate is obtained;

dissolving at least one soluble salt of a noble metal element and at least one soluble salt of a transition metal element in water to prepare a coating liquid stock solution for a first intermediate layer, wherein the total metal concentration in the aqueous solution is 210-240 g/L, and the molar percentage of the noble metal element is 6-8% and the molar percentage of the transition metal element is 92-94% according to metal components, so as to obtain the coating liquid stock solution for the first intermediate layer;

dissolving at least one soluble salt of a noble metal element and at least one soluble salt of a transition metal element in water to prepare a coating liquid stock solution for the second intermediate layer, wherein the total metal concentration in the aqueous solution is 210-240 g/L, and the molar percentage of the noble metal element is 11-13% and the molar percentage of the transition metal element is 87-89% based on metal components, so as to obtain the coating liquid stock solution for the second intermediate layer;

dissolving at least one soluble salt of a noble metal element and at least one soluble salt of a transition metal element in water to prepare a coating liquid stock solution for the third intermediate layer, wherein the total metal concentration in the aqueous solution is 210-240 g/L, and the molar percentage of the noble metal element is 16-18% and the molar percentage of the transition metal element is 82-84% based on metal components, so as to obtain the coating liquid stock solution for the third intermediate layer;

in the step C, adding a graphene aqueous solution into the coating liquid stock solution for the surface layer of the anode substrate obtained in the step B, wherein the graphene proportion is 0.2-2 g/L, and then stirring the salt solution by using an ultrasonic mixer to uniformly mix the salt solution to obtain an active coating liquid for the surface layer of the anode substrate;

adding a graphene aqueous solution into the coating liquid stock solution for the first intermediate layer obtained in the step B, wherein the ratio of graphene is 0.2-2 g/L, and then stirring the salt solution by using an ultrasonic mixer to uniformly mix the salt solution to obtain an active coating liquid for the first intermediate layer;

adding a graphene aqueous solution into the coating liquid stock solution for the second intermediate layer obtained in the step B, wherein the graphene proportion is 0.2-2 g/L, and then stirring the salt solution by using an ultrasonic mixer to uniformly mix the salt solution to obtain an active coating liquid for the second intermediate layer;

and D, adding a graphene aqueous solution into the coating liquid stock solution for the third intermediate layer obtained in the step B, wherein the ratio of graphene in the graphene aqueous solution is 0.2-2 g/L, and stirring the salt solution by using an ultrasonic mixer to uniformly mix the salt solution to obtain the active coating liquid for the third intermediate layer.

Preferably, in the step B, soluble salts of more than two noble metal elements and soluble salts of more than two transition metal elements are dissolved in water to prepare a coating liquid stock solution for the surface layer of the anode substrate, the concentration of all metals in the aqueous solution is 220 g/L-230 g/L, the molar percentage of the noble metal elements is 26% -30% and the molar percentage of the transition metal elements is 70% -74% based on the metal components, and the coating liquid stock solution for the surface layer of the anode substrate is obtained;

dissolving at least one soluble salt of a noble metal element and at least one soluble salt of a transition metal element in water to prepare a coating liquid stock solution for the first intermediate layer, wherein the total metal concentration in the aqueous solution is 220 g/L-230 g/L, and the molar percentage of the noble metal element and the molar percentage of the transition metal element are respectively 7% and 93%, based on the metal components, to obtain the coating liquid stock solution for the first intermediate layer;

dissolving at least one soluble salt of a noble metal element and at least one soluble salt of a transition metal element in water to prepare a coating liquid stock solution for the second intermediate layer, wherein the total metal concentration in the aqueous solution is 220 g/L-230 g/L, and the molar percentage of the noble metal element and the molar percentage of the transition metal element are respectively 12% and 88%, based on the metal components, so as to obtain the coating liquid stock solution for the second intermediate layer;

dissolving at least one soluble salt of a noble metal element and at least one soluble salt of a transition metal element in water to prepare a coating liquid stock solution for the third intermediate layer, wherein the total metal concentration in the aqueous solution is 220 g/L-230 g/L, and the molar percentage of the noble metal element and the molar percentage of the transition metal element are respectively 17% and 82%, based on the metal components, so as to obtain the coating liquid stock solution for the third intermediate layer;

in the step C, adding a graphene aqueous solution into the coating liquid stock solution for the surface layer of the anode substrate obtained in the step B, wherein the graphene proportion is 0.5-1.6 g/L, and then stirring the salt solution by using an ultrasonic mixer to uniformly mix the salt solution to obtain an active coating liquid for the surface layer of the anode substrate;

adding a graphene aqueous solution into the coating liquid stock solution for the first intermediate layer obtained in the step B, wherein the ratio of graphene is 0.5-1.6 g/L, and then stirring the salt solution by using an ultrasonic mixer to uniformly mix the salt solution to obtain an active coating liquid for the first intermediate layer;

adding a graphene aqueous solution into the coating liquid stock solution for the second intermediate layer obtained in the step B, wherein the ratio of graphene is 0.6-1.6 g/L, and then stirring the salt solution by using an ultrasonic mixer to uniformly mix the salt solution to obtain an active coating liquid for the second intermediate layer;

and D, adding a graphene aqueous solution into the coating liquid stock solution for the third intermediate layer obtained in the step B, wherein the ratio of graphene in the graphene aqueous solution is 0.6-1.6 g/L, and then stirring the salt solution by using an ultrasonic mixer to uniformly mix the salt solution to obtain the active coating liquid for the third intermediate layer.

Preferably, in the step D, the step of pickling the metal substrate of the anode for hydrogen production from alkaline water is to heat 18wt% hydrochloric acid to boiling and then pickle the metal substrate of the anode for hydrogen production from alkaline water for 3 to 5 minutes;

preferably, the soluble inorganic salt of the ruthenium element is ruthenium nitrate, the soluble inorganic salt of the iridium element is iridium nitrate, the soluble inorganic salt of the lanthanum element is lanthanum nitrate, the soluble inorganic salt of the nickel element is nickel nitrate, the soluble inorganic salt of the cobalt element is cobalt nitrate, and the single-layer coating amount of the active coating is 5.6g/m ² —6.0g/m ² 。

The preparation method of the anode for hydrogen production by alkaline water comprises the following steps:

A. preparing soluble salt of at least one noble metal element, wherein the noble metal element is ruthenium Ru, iridium Ir, rhodium Rh, palladium Pd or platinum Pt; preparing at least one soluble salt of transition metal elements, wherein the transition metal elements are lanthanum La, iron Fe, cobalt Co, nickel Ni or copper Cu;

B. dissolving at least one soluble salt of a noble metal element and at least one soluble salt of a transition metal element in water to prepare a coating liquid stock solution for the surface layer of the anode substrate, wherein the total metal concentration in the aqueous solution is 200-250 g/L, and the molar percentage of the noble metal element is 20-35% and the molar percentage of the transition metal element is 65-80% according to the metal components to obtain the coating liquid stock solution for the surface layer of the anode substrate;

adding a graphene aqueous solution into the coating liquid stock solution for the second intermediate layer obtained in the step B, wherein the ratio of graphene is 0.1-3 g/L, and then stirring the salt solution by using an ultrasonic mixer to uniformly mix the salt solution to obtain an active coating liquid for the second intermediate layer;

F. coating the coating liquid stock solution for the first intermediate layer obtained in the step C on the metal substrate obtained in the step E, then carrying out heat treatment on the metal substrate coated with the coating liquid stock solution for the first intermediate layer in an oxygen-containing atmosphere, wherein the heat treatment condition is 350-400 ℃, keeping the temperature for 5-10 minutes, raising the temperature of the furnace to 400-550 ℃ within 5 minutes, keeping the temperature for 10-50 minutes, rapidly cooling the metal substrate to room temperature after the heat treatment is finished, and generating an active coating on the outer surface of the metal substrate, wherein the single-layer coating amount of the active coating is 4.2g/m & lt 2 & gt-6.3 g/m & lt 2 & gt ² ；

Then coating the coating liquid stock solution for the first intermediate layer obtained in the step C again, and then coating the coating liquid stock solution for the first intermediate layer in an oxygen-containing atmosphereThe metal matrix is subjected to heat treatment, the heat treatment condition is 350-400 ℃, the temperature is kept for 5-10 minutes, the furnace temperature is increased to 400-550 ℃ within 5 minutes, the temperature is kept for 10-50 minutes, the metal matrix is rapidly cooled to room temperature after the heat treatment is finished, an active coating is generated on the outer surface of the metal matrix again, and the single-layer coating amount of the active coating is 4.2g/m ² —6.3g/m ² ；

H. C, coating the coating liquid stock solution for the third intermediate layer obtained in the step C on the metal substrate obtained in the step G, then carrying out heat treatment on the metal substrate coated with the coating liquid stock solution for the third intermediate layer in an oxygen-containing atmosphere, wherein the heat treatment condition is 350-400 ℃, the heat preservation time is 5-10 minutes, the furnace temperature is increased to 400-550 ℃ within 5 minutes, the heat preservation time is 10-50 minutes, after the heat treatment is finished, the metal substrate is rapidly cooled to the room temperature, and an active coating is generated on the outer surface of the metal substrate, wherein the single-layer coating amount of the active coating is 4.2G/m ² —6.3g/m ² ；

Then, the coating liquid stock solution for the third intermediate layer obtained in the step C is applied again, and then the metal base coated with the coating liquid stock solution for the third intermediate layer is applied in an oxygen-containing atmosphereCarrying out heat treatment on the metal substrate, wherein the heat treatment condition is 350-400 ℃, the temperature is kept for 5-10 minutes, the furnace temperature is increased to 400-550 ℃ within 5 minutes, the temperature is kept for 10-50 minutes, after the heat treatment is finished, the metal substrate is rapidly cooled to the room temperature, an active coating is generated on the outer surface of the metal substrate again, and the single-layer coating amount of the active coating is 4.2g/m ² —6.3g/m ² ；

I. Coating the surface layer of the anode substrate obtained in the step C on the metal matrix treated in the step H by using the active coating solution, then carrying out heat treatment on the metal matrix coated with the coating solution in an oxygen-containing atmosphere, wherein the heat treatment condition is 350-400 ℃, keeping the temperature for 5-10 minutes, raising the temperature of the furnace to 400-550 ℃ within 5 minutes, keeping the temperature for 10-50 minutes, rapidly cooling the metal matrix to room temperature after the heat treatment is finished, and generating an active coating on the outer surface of the metal matrix, wherein the single-layer coating amount of the active coating is 4.2g/m ² —6.3g/m ² ；

K. And D, performing firing heat treatment on the metal matrix obtained in the step J, wherein the firing heat treatment temperature is 350-500 ℃, the firing heat treatment time is 50-100 minutes, and rapidly cooling the metal matrix to room temperature after the heat treatment is finished to obtain the anode for hydrogen production by alkaline water.

Preferably, in the step B, soluble salts of more than two noble metal elements and soluble salts of more than two transition metal elements are dissolved in water to prepare a coating liquid stock solution for the surface layer of the anode substrate, the concentration of all metals in the aqueous solution is 210 g/L-240 g/L, the molar percentage of the noble metal elements is 23% -33% and the molar percentage of the transition metal elements is 67% -77% based on the metal components, and the coating liquid stock solution for the surface layer of the anode substrate is obtained;

adding a graphene aqueous solution into the coating liquid stock solution for the second intermediate layer obtained in the step B, wherein the ratio of graphene is 0.2-2 g/L, and then stirring the salt solution by using an ultrasonic mixer to uniformly mix the salt solution to obtain an active coating liquid for the second intermediate layer;

and D, adding a graphene aqueous solution into the coating liquid stock solution for the third intermediate layer obtained in the step B, wherein the ratio of graphene in the graphene aqueous solution is 0.6-1.6 g/L, and stirring the salt solution by using an ultrasonic mixer to uniformly mix the salt solution to obtain the active coating liquid for the third intermediate layer.

Preferably, in the step D, the step of pickling the metal substrate of the anode for hydrogen production from alkaline water is to use 18wt% hydrochloric acid, heat the 18wt% hydrochloric acid to boiling, and then pickle the metal substrate of the anode for hydrogen production from alkaline water for 3-5 minutes;

The anode for hydrogen production from alkaline water and the preparation method thereof adopt at least one soluble salt Ru, ir, rh, pd, pt of noble metal elements and at least one soluble salt La, fe, co, ni, cu of transition metal elements to dissolve in water, the concentration of all metals in the water solution is 200 g/L-250 g/L, according to the metal components, graphene is added into the water solution, the proportion of the graphene is 0.1 g/L-3 g/L, and then an ultrasonic mixer is used for stirring the salt solution to mix the salt solution uniformly, so as to obtain an active coating masking liquid; by adding graphene into the active coating liquid, the surface appearance of the anode can be improved, and the active coating liquid is utilizedAn anode for hydrogen production by electrolyzing water prepared from the coating solution with a chemical composition, wherein the anode is electrolyzed at 80 deg.C and 32% NaOH for 2000 hr to obtain a solution with a concentration of 6KA/m ² Electrolyzing for 1278 hours at 8KA/m ² After electrolysis for 722 hours, the coating residue is 75 percent; 6KA/m ² Then, the oxygen evolution overpotential was measured at 180mV. Therefore, the anode for hydrogen production from alkaline water and the preparation method thereof have low oxygen evolution overpotential and 6KA/m 2-8 KA/m ² Has long service life under high current density.

According to the anode for hydrogen production from alkaline water and the preparation method thereof, graphene is added into the active coating masking liquid to improve the microstructure of the anode coating, so that the surface of the coating is cellular, the surface cracks of the coating are fine and small, the uneven surface characteristics are generated, the surface roughness of the electrode is increased, the number of active points on the surface of the anode is increased, the electrocatalytic activity of the electrode is improved, and the oxygen evolution overpotential is effectively reduced. In addition, the anode for hydrogen production by alkaline water also adopts a gradient coating method, so that the bonding force between the base material and the coating can be improved, the components of the base material and the coating are effectively prevented from mutating, and the service life of the electrode is prolonged. Through the two modes, the anode for preparing hydrogen from alkaline water has three advantages:

(1) Low oxygen evolution overpotential;

(2) Can be at 6KA/m ² And above high current density;

(3) Has longer service life.

Other details and characteristics of the anode for hydrogen production from alkaline water and the method for producing the same according to the present invention will be apparent from the examples described in detail below.

Detailed Description

dissolving at least one soluble salt of a noble metal element and at least one soluble salt of a transition metal element in water to prepare a coating liquid stock solution for the third intermediate layer, wherein the total metal concentration in the aqueous solution is 200-250 g/L, and the molar percentage of the noble metal element is 15-19% and the molar percentage of the transition metal element is 81-85% according to metal components to obtain the coating liquid stock solution for the third intermediate layer;

H. Coating the coating liquid stock solution for the third intermediate layer obtained in the step C on the metal substrate obtained in the step G, then carrying out heat treatment on the metal substrate coated with the coating liquid stock solution for the third intermediate layer in an oxygen-containing atmosphere, wherein the heat treatment condition is 350-400 ℃, keeping the temperature for 5-10 minutes, raising the temperature of the furnace to 400-550 ℃ within 5 minutes, keeping the temperature for 10-50 minutes, rapidly cooling the metal substrate to room temperature after the heat treatment is finished, and generating an active coating on the outer surface of the metal substrate, wherein the single-layer coating amount of the active coating is 4.2G/m ² —6.3g/m ² ；

The coating method disclosed in the above steps B to J is a gradient coating method.

In a further improvement of the present invention, in the step B, a coating liquid stock solution for the surface layer of the anode base material is prepared by dissolving soluble salts of two or more noble metal elements and soluble salts of two or more transition metal elements in water, wherein the total metal concentration in the aqueous solution is from 210g/L to 240g/L, and the coating liquid stock solution for the surface layer of the anode base material is obtained by using the molar percentage of the noble metal elements in terms of metal components from 23% to 33% and the molar percentage of the transition metal elements in terms of metal components from 67% to 77%;

in the step C, adding a graphene aqueous solution into the coating liquid stock solution for the surface layer of the anode base material obtained in the step B, wherein the ratio of graphene is 0.2-2 g/L, and then stirring the salt solution by using an ultrasonic mixer to uniformly mix the salt solution to obtain an active coating liquid for the surface layer of the anode base material;

In the step B, soluble salts of more than two noble metal elements and soluble salts of more than two transition metal elements are dissolved in water to prepare a coating liquid stock solution for the surface layer of the anode substrate, the concentration of all metals in the aqueous solution is 220 g/L-230 g/L, wherein the molar percentage of the noble metal elements is 26-30% and the molar percentage of the transition metal elements is 70-74% based on the metal components, so as to obtain the coating liquid stock solution for the surface layer of the anode substrate;

dissolving at least one soluble salt of a noble metal element and at least one soluble salt of a transition metal element in water to prepare a coating liquid stock solution for the third intermediate layer, wherein the total metal concentration in the aqueous solution is 220-230 g/L, and the molar percentage of the noble metal element and the molar percentage of the transition metal element are respectively 17% and 82% according to the metal components, so as to obtain the coating liquid stock solution for the third intermediate layer;

As a further improvement of the invention, in the step D, the metal substrate of the anode for hydrogen production from alkaline water is subjected to acid washing by using 18wt% hydrochloric acid, and after the 18wt% hydrochloric acid is heated to boiling, the metal substrate of the anode for hydrogen production from alkaline water is subjected to acid washing treatment for 3-5 minutes;

as a further improvement of the invention, the soluble inorganic salt of the ruthenium element is ruthenium nitrate, the soluble inorganic salt of the iridium element is iridium nitrate, the soluble inorganic salt of the lanthanum element is lanthanum nitrate, the soluble inorganic salt of the nickel element is nickel nitrate, the soluble inorganic salt of the cobalt element is cobalt nitrate, and the single-layer coating amount of the active coating is 5.6g/m ² —6.0g/m ² 。

The preparation method of the anode for hydrogen production from alkaline water comprises the following steps:

A. preparing soluble salt of at least one noble metal element, wherein the noble metal element is ruthenium Ru, iridium Ir, rhodium Rh, palladium Pd or platinum Pt; preparing soluble salt of at least one transition metal element, wherein the transition metal element is lanthanum La, iron Fe, cobalt Co, nickel Ni or copper Cu;

G. Coating the metal substrate obtained in step F with the coating liquid stock solution for the second intermediate layer obtained in step C, and then coating the coated second intermediate layer in an oxygen-containing atmosphereHeat treating the metal substrate in the liquid stock solution at 350-400 deg.C for 5-10 min, heating the furnace to 400-550 deg.C within 5 min, maintaining for 10-50 min, cooling to room temperature, and forming an active coating on the outer surface of the metal substrate, wherein the single-layer coating amount of the active coating is 4.2g/m ² —6.3g/m ² ；

I. C, coating the surface layer of the anode base material obtained in the step C with an active coating solution on the metal base body treated in the step H, and then coating the gold of the coating solution in an oxygen-containing atmosphereThe method comprises the steps of carrying out heat treatment on a metal substrate, wherein the heat treatment condition is 350-400 ℃, keeping the temperature for 5-10 minutes, heating the furnace to 400-550 ℃ within 5 minutes, keeping the temperature for 10-50 minutes, rapidly cooling the metal substrate to room temperature after the heat treatment is finished, and generating an active coating on the outer surface of the metal substrate, wherein the single-layer coating amount of the active coating is 4.2g/m ² —6.3g/m ² ；

In a further improvement of the present invention, in the step B, a coating liquid stock solution for the surface layer of the anode substrate is prepared by dissolving soluble salts of two or more noble metal elements and soluble salts of two or more transition metal elements in water, wherein the total metal concentration in the aqueous solution is from 210g/L to 240g/L, and the coating liquid stock solution for the surface layer of the anode substrate is obtained by controlling the mole percentage of the noble metal elements to be from 23% to 33% and the mole percentage of the transition metal elements to be from 67% to 77%, based on the metal components;

dissolving at least one soluble salt of a noble metal element and at least one soluble salt of a transition metal element in water to prepare a coating liquid stock solution for a first intermediate layer, wherein the total metal concentration in the aqueous solution is 210-240 g/L, and the molar percentage of the noble metal element is 6-8% and the molar percentage of the transition metal element is 92-94% based on metal components, so as to obtain the coating liquid stock solution for the first intermediate layer;

and D, adding a graphene aqueous solution into the coating liquid stock solution for the third intermediate layer obtained in the step B, wherein the ratio of graphene in the graphene aqueous solution is 0.2-2 g/L, and then stirring the salt solution by using an ultrasonic mixer to uniformly mix the salt solution to obtain the active coating liquid for the third intermediate layer.

in the step C, adding a graphene aqueous solution into the coating liquid stock solution for the surface layer of the anode base material obtained in the step B, wherein the ratio of graphene is 0.5-1.6 g/L, and then stirring the salt solution by using an ultrasonic mixer to uniformly mix the salt solution to obtain an active coating liquid for the surface layer of the anode base material;

The mass percentages of the elements in the active coating layer in terms of metal components can be detected by an X-ray fluorescence tester.

Example 1

Preparing a coating solution: mixing ruthenium nitrate solution, nickel nitrate and cobalt nitrate until the ruthenium nitrate solution, the nickel nitrate and the cobalt nitrate are completely dissolved, so that the atomic percentage content of the ruthenium nitrate solution is Ru:30%, ni:14%, co:56 percent, the concentration of all metals reaches 220g/L, and finally, adding a graphene aqueous solution into the solution dissolved with ruthenium nitrate, nickel nitrate and cobalt nitrate according to the proportion that the content of graphene in the solution is 0.4g/L, and uniformly mixing the solution by using an ultrasonic instrument to obtain a surface active coating masking liquid; the atomic percentage content of the first gradient interlayer Ru:8%, ni:74%, co:18%, the atomic percentage content of the second gradient interlayer Ru:16%, ni:54%, co:30%, and the atomic percentage content of the third gradient interlayer Ru:25%, ni:34%, co:41 percent, the concentration of all metals reaches 220g/L, finally, adding a graphene aqueous solution into the solution dissolved with ruthenium nitrate, nickel nitrate and cobalt nitrate according to the proportion that the content of graphene in the solution is 0.4g/L, and uniformly mixing by using an ultrasonic instrument to obtain the gradient interlayer coating liquid.

Coating and baking: uniformly brushing the active coating liquid on a pretreated metal substrate made of a titanium expanded mesh, wherein the coating sequence is as follows: the first gradient interlayer is 2 times, the second gradient interlayer is 2 times, the third gradient interlayer is 2 times, and the surface active coating is 3 times. After each coating, baking at 400 ℃ for 30 minutes to ensure that the coating amount is more than or equal to 45g/m ² And the last heat treatment time is 60 minutes, so that the anode for preparing hydrogen from alkaline water is obtained.

Electrolyzing the above alkaline water-based anode for hydrogen production in NaOH at 80 deg.C and 32% for 2000 hr, wherein the concentration is 6KA/m ² The electrolysis lasts for 1278 hours, 8KA/m2 is electrolyzed for 722 hours, and the residual quantity of the coating is 75 percent; 6KA/m ² Then, the oxygen evolution overpotential was measured at 180mV.

Example 2

Preparing a coating solution: mixing ruthenium nitrate solution, nickel nitrate and cobalt nitrate until the ruthenium nitrate solution, the nickel nitrate and the cobalt nitrate are completely dissolved, so that the atomic percentage content of the ruthenium nitrate solution is Ru:30%, ni:14%, co:56 percent, the concentration of all metals reaches 230g/L, and finally, adding a graphene aqueous solution into the solution dissolved with ruthenium nitrate, nickel nitrate and cobalt nitrate according to the proportion that the content of graphene in the solution is 0.4g/L, and uniformly mixing the graphene aqueous solution with an ultrasonic instrument to obtain a surface active coating masking liquid; the atomic percent content of the first gradient interlayer Ru:8%, ni:74%, co:18%, the atomic percentage content of the second gradient interlayer Ru:16%, ni:54%, co:30%, and the atomic percentage content of the third gradient interlayer Ru:25%, ni:34%, co:41 percent, the concentration of all metals reaches 230g/L, finally, adding a graphene aqueous solution into the solution dissolved with ruthenium nitrate, nickel nitrate and cobalt nitrate according to the proportion that the content of graphene in the solution is 1g/L, and uniformly mixing the solution by using an ultrasonic instrument to obtain the gradient interlayer coating liquid.

Coating and baking: uniformly coating the active coating solution on a pretreated metal substrate made of a titanium expanded metal, wherein the coating sequence is as follows: first gradient interlayer 2 times, second gradient interlayer2 times, the third gradient middle layer 2 times, and the surface active coating 3 times. After each coating, baking at 400 ℃ for 30 minutes to ensure that the coating amount is more than or equal to 45g/m ² And the last heat treatment time is 60 minutes, so that the anode for preparing hydrogen from alkaline water is obtained.

The above-mentioned anode for producing hydrogen from alkaline water was electrolyzed at 80 ℃ in 32% NaOH solution for 2000 hours, wherein the concentration was 6KA/m ² The electrolysis lasts for 1278 hours, 8KA/m2 is electrolyzed for 722 hours, and the residual quantity of the coating is 70 percent; 6KA/m ² Then, the oxygen evolution overpotential was measured at 205mV.

Comparative example 1

Preparing a coating solution: mixing ruthenium nitrate solution, nickel nitrate and cobalt nitrate until the ruthenium nitrate solution, the nickel nitrate and the cobalt nitrate are completely dissolved, so that the atomic percentage content of the ruthenium nitrate solution is Ru:30%, ni:14%, co:56 percent, and the concentration of all metals reaches 220g/L to obtain surface active coating masking liquid; the atomic percent content of the first gradient interlayer Ru:8%, ni:74%, co:18%, the atomic percentage content of the second gradient interlayer Ru:16%, ni:54%, co:30%, and the atomic percentage content of the third gradient interlayer Ru:25%, ni:34%, co:41 percent, and the concentration of all metals reaches 220g/L to obtain the gradient intermediate layer coating liquid.

Electrolyzing the anode for hydrogen production with alkaline water at 80 deg.C and 32% NaOH for 1000 hr, wherein 6KA/m2 is electrolyzed for 639 hr and 8KA/m ² The electrolytic time is 361 hours, and the residual quantity of the coating is 55 percent; 6KA/m ² Then, the oxygen evolution overpotential was measured at 230mV.

Comparative example 2

Preparing a masking liquid: mixing ruthenium nitrate solution, nickel nitrate and cobalt nitrate until the ruthenium nitrate solution, the nickel nitrate and the cobalt nitrate are completely dissolved, so that the atomic percentage content of the ruthenium nitrate solution is Ru:30%, ni:14%, co:56 percent, the concentration of all metals reaches 220g/L, and finally, adding a graphene aqueous solution into the solution dissolved with ruthenium nitrate, nickel nitrate and cobalt nitrate according to the proportion that the content of graphene in the solution is 0.25 g/L-1 g/L, and uniformly mixing the solution by using an ultrasonic instrument to obtain the active coating liquid.

Coating and baking: uniformly coating the active coating solution on a pretreated metal substrate made of a titanium expanded metal, coating for 9 times, baking at 400 ℃ after each coating, and performing heat treatment for 30 minutes to ensure that the coating amount is more than or equal to 45g/m ² And the last heat treatment time is 60 minutes, so that the anode for preparing hydrogen from alkaline water is obtained.

The anode for producing hydrogen from alkaline water is electrolyzed at 80 deg.C and 32% NaOH concentration for 1000 hr, wherein the concentration is 6KA/m ² Electrolysis for 639 hours, 8KA/m ² The electrolytic time is 361 hours, the residual quantity of the coating is 35 percent; 6KA/m ² Then, the oxygen evolution overpotential was 185mV.

As can be seen from the comparison of examples with comparative examples, the anode for hydrogen production from alkaline water of the present invention was electrolyzed at 80 ℃ in 32% NaOH for 2000 hours, wherein 6KA/m ² Electrolyzing for 1278 hours at 8KA/m ² After electrolysis for 722 hours, the coating residue is 75 percent; 6KA/m ² Then, the oxygen evolution overpotential was measured at 180mV. Therefore, the alkaline water hydrogen production anode has the characteristics of low chlorine evolution overpotential and long operation life under high current density, so that the small volume, low energy consumption, stability and long operation time of the water electrolysis hydrogen production complete equipment are ensured.

The above-mentioned embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solution of the present invention by those skilled in the art should fall within the protection scope defined by the claims of the present invention without departing from the spirit of the present invention.

Claims

1. The anode for producing hydrogen from alkaline water is characterized in that: the method comprises the following steps:

Coating the coating liquid stock solution for the first intermediate layer obtained in the step C again, and then carrying out heat treatment on the metal substrate coated with the coating liquid stock solution for the first intermediate layer in an oxygen-containing atmosphere, wherein the heat treatment condition is 350-400 ℃, the temperature is kept for 5-10 minutes, and the furnace temperature is increased within 5 minutesKeeping the temperature for 10-50 minutes to 400-550 ℃, rapidly cooling to room temperature after the heat treatment is finished, and generating an active coating on the outer surface of the metal substrate again, wherein the single-layer coating amount of the active coating is 4.2g/m ² —6.3g/m ² ；

Coating the coating liquid stock solution for the third intermediate layer obtained in the step C again, and then carrying out heat treatment on the metal substrate coated with the coating liquid stock solution for the third intermediate layer in an oxygen-containing atmosphere, wherein the heat treatment condition is 350-400 ℃, the temperature is kept for 5-10 minutes, the furnace temperature is increased to 400-550 ℃ within 5 minutes, and the temperature is keptCooling to room temperature rapidly after heat treatment for 10-50 min, and forming an active coating on the outer surface of the metal substrate, wherein the single-layer coating amount of the active coating is 4.2g/m ² —6.3g/m ² ；

2. The anode for producing hydrogen from alkaline water according to claim 1, characterized in that: in the step B, soluble salts of more than two noble metal elements and soluble salts of more than two transition metal elements are dissolved in water to prepare a coating liquid stock solution for the surface layer of the anode substrate, the concentration of all metals in the aqueous solution is 210 g/L-240 g/L, and the coating liquid stock solution for the surface layer of the anode substrate is obtained according to metal components, wherein the mole percentage of the noble metal elements is 23% -33%, and the mole percentage of the transition metal elements is 67% -77%;

dissolving at least one soluble salt of a noble metal element and at least one soluble salt of a transition metal element in water to prepare a coating liquid stock solution for a second intermediate layer, wherein the total metal concentration in the aqueous solution is 210-240 g/L, and the molar percentage of the noble metal element is 11-13% and the molar percentage of the transition metal element is 87-89% based on metal components, so as to obtain the coating liquid stock solution for the second intermediate layer;

3. The anode for producing hydrogen from alkaline water according to claim 2, characterized in that: in the step B, more than two soluble salts of noble metal elements and more than two soluble salts of transition metal elements are dissolved in water to prepare a coating liquid stock solution for the surface layer of the anode substrate, the concentration of all metals in the aqueous solution is 220 g/L-230 g/L, and the coating liquid stock solution for the surface layer of the anode substrate is obtained according to metal components, wherein the mole percentage of the noble metal elements is 26% -30%, and the mole percentage of the transition metal elements is 70% -74%;

dissolving at least one soluble salt of a noble metal element and at least one soluble salt of a transition metal element in water to prepare a coating liquid stock solution for the second intermediate layer, wherein the total metal concentration in the aqueous solution is 220-230 g/L, and the molar percentage of the noble metal element and the molar percentage of the transition metal element are respectively 12% and 88%, based on metal components, to obtain the coating liquid stock solution for the second intermediate layer;

4. The anode for producing hydrogen from alkaline water according to claim 3, characterized in that: d, pickling the metal substrate of the anode for hydrogen production from alkaline water by adopting 18wt% hydrochloric acid, heating the 18wt% hydrochloric acid to boiling, and carrying out pickling treatment on the metal substrate of the anode for hydrogen production from alkaline water for 3-5 minutes;

5. the anode for hydrogen production from alkaline water according to any one of claims 1 to 4, characterized in that the soluble inorganic salt of ruthenium element is ruthenium nitrate, the soluble inorganic salt of iridium element is iridium nitrate, the soluble inorganic salt of lanthanum element is lanthanum nitrate, the soluble inorganic salt of nickel element is nickel nitrate, the soluble inorganic salt of cobalt element is cobalt nitrate, and the single-layer coating amount of the active coating is 5.6g/m ² —6.0g/m ² 。

6. The preparation method of the anode for hydrogen production by alkaline water is characterized by comprising the following steps: which comprises the following steps:

Then coating the coating liquid stock solution for the first intermediate layer obtained in the step C again, and then performing heat treatment on the metal substrate coated with the coating liquid stock solution for the first intermediate layer in an oxygen-containing atmosphere under the heat treatment condition of 350-400 DEG CKeeping the temperature for 5-10 minutes, heating the furnace to 400-550 ℃ within 5 minutes, keeping the temperature for 10-50 minutes, rapidly cooling the furnace to room temperature after the heat treatment is finished, and generating an active coating on the outer surface of the metal matrix again, wherein the single-layer coating amount of the active coating is 4.2g/m ² —6.3g/m ² ；

Then coating the coating liquid stock solution for the third intermediate layer obtained in the step C again, then carrying out heat treatment on the metal substrate coated with the coating liquid stock solution for the third intermediate layer in an oxygen-containing atmosphere, wherein the heat treatment condition is 350-400 ℃, keeping the temperature for 5-10 minutes,heating the furnace to 400-550 deg.C within 5 min, maintaining the temperature for 10-50 min, cooling to room temperature after heat treatment, and forming an active coating on the outer surface of the metal substrate with a single-layer coating amount of 4.2g/m ² —6.3g/m ² ；

7. The method of making an anode for hydrogen production from alkaline water according to claim 6, characterized in that: in the step B, soluble salts of more than two noble metal elements and soluble salts of more than two transition metal elements are dissolved in water to prepare a coating liquid stock solution for the surface layer of the anode substrate, the concentration of all metals in the aqueous solution is 210 g/L-240 g/L, and the coating liquid stock solution for the surface layer of the anode substrate is obtained according to metal components, wherein the mole percentage of the noble metal elements is 23% -33%, and the mole percentage of the transition metal elements is 67% -77%;

8. The method of making an anode for hydrogen production from alkaline water according to claim 7, characterized in that: in the step B, more than two soluble salts of noble metal elements and more than two soluble salts of transition metal elements are dissolved in water to prepare a coating liquid stock solution for the surface layer of the anode substrate, the concentration of all metals in the aqueous solution is 220 g/L-230 g/L, and the coating liquid stock solution for the surface layer of the anode substrate is obtained according to metal components, wherein the mole percentage of the noble metal elements is 26% -30%, and the mole percentage of the transition metal elements is 70% -74%;

9. The method of making an anode for hydrogen production from alkaline water according to claim 8, characterized in that: and D, the step D of pickling the metal matrix of the anode for hydrogen production from alkaline water is to adopt 18wt% of hydrochloric acid, heat the 18wt% of hydrochloric acid to boiling, and then carry out pickling treatment on the metal matrix of the anode for hydrogen production from alkaline water for 3-5 minutes.

10. The method for producing an anode for hydrogen with alkaline water according to any one of claims 6 to 9, characterized in that the soluble inorganic salt of ruthenium element is ruthenium nitrate, the soluble inorganic salt of iridium element is iridium nitrate, the soluble inorganic salt of lanthanum element is lanthanum nitrate, the soluble inorganic salt of nickel element is nickel nitrate, the soluble inorganic salt of cobalt element is cobalt nitrate, and the single-layer coating amount of the active coating is 5.6g/m ² —6.0g/m ² 。