CN112251765B - A lead net-based water splitting hydrogen production device and its preparation method and use method - Google Patents

Abstract

The invention discloses a lead mesh-based water-splitting hydrogen production device, a preparation method and a use method thereof. The invention provides a method for preparing an anode of a high-efficiency PEM hydrolysis device by using non-noble metals, which has simple system structure and low price; and the anode based on the lead net can stabilize electrochemical hydrolysis reaction under acidic and high temperature (above 60 ℃).

Description

A lead net-based water splitting hydrogen production device and its preparation method and use method

technical field

The invention belongs to the technical field of power supplies, and in particular relates to a water splitting hydrogen production device based on lead grids, a preparation method and a use method thereof.

Background technique

Hydrogen is the substance with the highest energy density, up to 33.3 kWh/kg, and is used as a secondary energy carrier, for example as rocket fuel. Hydrogen widely exists in hydrocarbons and water, and is one of the most abundant elements on earth. When fossil energy is reformed, a large amount of hydrogen is produced as a by-product. Compared with this, the amount of hydrogen produced by electrolysis of water is negligible. However, clean energy such as wind energy and solar energy can produce high-purity hydrogen through electrochemical reaction hydrolysis, so it has become a very popular hydrogen production technology. At present, hydrogen production by alkaline hydrolysis devices is dominant, but acidic proton exchange membrane (PEM) hydrolysis devices have the advantages of fast response, energy saving, and high integration, so they have also received attention.

At present, the electrodes suitable for PEM hydrolysis devices are mainly noble metal electrodes, such as platinum, platinum oxide or platinum alloys as cathodes, and ruthenium, rubidium or their oxides and alloys as anodes. The scarcity and high price of precious metals lead to the extremely high cost of the PEM hydrolysis device. Non-noble metal materials or their compounds, especially transition metal materials or their compounds, are extremely unstable in acid, and their hydrogen production efficiency decays rapidly during high-temperature hydrolysis.

Contents of the invention

Based on the problems existing in the prior art, the present invention provides a water splitting hydrogen production device based on lead grid and its preparation method and use method. A low-dimensional lead oxide sheet is grown to serve as the anode of the PEM hydrolysis device. Moreover, in the present invention, without using precious metals, a stable hydrolysis hydrogen production process can be realized at a high temperature of 60° C., improving hydrogen production efficiency and reducing costs.

According to the first aspect of the technical solution of the present invention, a water splitting hydrogen production device based on a lead grid is proposed, which includes an anode, a cathode and a diaphragm, which uses a lead grid or a lead grid covered with lead oxide flakes as an anode, and uses a hot-pressed platinum Carbon PEM or platinum-coated lead mesh or titanium mesh or alloy mesh is used as cathode, and PEM is used as separator.

Among them, the anode, diaphragm and cathode are stacked in sequence to form the main body of the water splitting hydrogen production device. The extension section of the anode and the extension section of the cathode are respectively provided with DC power interfaces.

Preferably, the proton exchange membrane (PEM) is a perfluorosulfonic acid type proton exchange membrane, a Nafion recast membrane, a non-fluoropolymer proton exchange membrane or a new composite proton exchange membrane. The anode is made of grid material, and the anode is a composite metal mesh of lead metal, alloy or platinum-plated, titanium, zinc oxide, or titanium oxide.

According to the second aspect of the technical solution of the present invention, a method for preparing a lead grid-based water splitting hydrogen production device is proposed, and the method includes the following steps.

Step 1, prepare anode lead mesh; purchase lead foil, and use a hole punching machine or a laser engraving machine to drill holes in the lead foil to prepare a lead mesh for use as an anode.

Step 2, prepare the cathode, and use a sputter coater to coat a layer of nano-platinum gold on the lead foil and use it directly as the cathode.

In step 3, the proton exchange membrane is interposed between the anode and the cathode, and the above anode-diaphragm-cathode is clamped with the shell protective layer and the fixing clip, and a water splitting hydrogen production device based on lead mesh is prepared.

Further, in step 1, a sputter coater is used to coat a layer of nano-platinum gold on the lead foil directly as an anode.

Further, in step 1, put the lead grid in a polytetrafluoroethylene cup filled with concentrated ammonia water, react under high temperature and high pressure at 180°C for 6 hours to 72 hours, and grow a layer of lead oxide sheet on the lead grid as an anode.

Further, the step 2 directly manufactures the platinum carbon PEM membrane for the anode of the proton exchange membrane (PEM) fuel cell as the cathode and the diaphragm of the hydrogen production device.

According to the third aspect of the technical solution of the present invention, a method for using a lead grid-based water splitting hydrogen production device is proposed, which includes the following steps.

Step 1, connect the DC power interface to the DC power supply, and connect the anode to the positive pole of the power supply, and connect the cathode to the negative pole of the power supply.

Step 2, place the water splitting hydrogen production device based on the lead grid in the acidic aqueous solution, set the DC power interface on the liquid surface, and avoid the contact between the circuit and the aqueous solution.

Step 3. Turn on the power switch, slowly increase the voltage from 2 V, and adjust to an appropriate voltage according to the hydrogen demand. If the hydrogen demand is large, the voltage will be high, and if the hydrogen demand is small, the voltage will be low.

Step 4: After the gas preparation is completed, first adjust the DC power supply to a low voltage, then turn off the DC power supply, and finally disconnect the DC power supply interface from the DC power supply.

Compared with the prior art, the present invention has the following beneficial effects.

First, the present invention proposes a method for preparing an anode of a high-efficiency PEM hydrolysis device with a non-noble metal, and the system structure is simple and the price is cheap.

Second, the lead grid-based anode proposed by the present invention is stable in electrochemical hydrolysis reaction under acidic and high temperature (above 60 °C).

Description of drawings

Fig. 1 is a schematic diagram of a water splitting hydrogen production device based on a lead grid according to the present invention.

Fig. 2 is a schematic diagram of the structure of the anode according to the present invention.

Fig. 3-1 is a schematic diagram of the structure of the cathode according to the present invention.

Fig. 3-2 is a schematic diagram of the film-making process according to the present invention.

Figure 4-1 is a photograph of the anode shown in accordance with the present invention.

Fig. 4-2 is a scanning electron micrograph according to the present invention.

Fig. 5 is a hydrolysis performance curve of an anode according to the present invention.

Fig. 6 is a performance curve of a hydrogen production device according to the present invention.

Wherein reference numerals: "1" indicates "anode", "2" indicates "cathode", "3" indicates "PEM", and "4" indicates "DC power interface".

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Apparently, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention. Additionally, the protection scope of the present invention should not be limited only to the specific experimental methods or specific parameters described below.

Starting from the stability of lead-based materials in acid, the present invention designs a water splitting hydrogen production device based on lead grids, in which lead grids or lead grids covered with lead oxide flakes are used as anodes, and hot-pressed platinum carbon PEM or Platinum-coated lead mesh (titanium mesh or alloy mesh) is used as the cathode, and PEM is used as the diaphragm. The invention can also grow low-dimensional lead oxide sheets on the lead metal grid by processing the lead metal grid, as the anode of the PEM hydrolysis device, which can achieve the purpose of stable hydrolysis hydrogen production at a high temperature of 60 °C, improve hydrogen production efficiency and reduce costs . Noble metals are used in the present invention.

As shown in Figure 1, the water splitting hydrogen production device based on lead mesh includes an anode 1, a cathode 2 and a diaphragm 3, and the diaphragm is preferably PEM, wherein the anode 1, diaphragm 3 and cathode 2 are stacked in sequence to form a water splitting system. The main body of the hydrogen device is provided with a DC power interface 4 on the extension section of the anode 1 and the extension section of the cathode 2 respectively. During the hydrogen production process, the DC power supply is connected to the device through the DC power supply interface 4, and the electrons flowing out of the negative electrode of the power supply flow into the electrolyte through the cathode 2, and at the same time, a reduction reaction occurs on the surface of the cathode, and hydrogen ions in the electrolyte near the cathode are generated by electrons. Hydrogen; holes flowing out of the positive electrode of the power supply flow into the electrolyte through the anode 1, and an oxidation reaction occurs on the surface of the anode electrode at the same time, and the hydroxide ions in the electrolyte near the anode lose electrons to generate oxygen. In addition, during the hydrogen production process, the electrons in the power supply flow into the electrolyte through the cathode 2, and hydrogen gas is generated on the surface of the cathode electrode.

Its chemical reaction formula is as follows.

Anode: 2H ₂ O=O ₂ ↑+4H ⁺ +4e-

Cathode: 4H ⁺ +4e-=2H ₂ ↑

Overall reaction formula: 2H ₂ O = H ₂ ↑+O ₂ ↑

According to Faraday's law of electrolysis, the gas production is proportional to the current.

As the PEM (proton exchange membrane) of the diaphragm, the proton exchange membrane that meets the following conditions is preferred: good proton conductivity, small electroosmosis of water molecules in the membrane, as little gas permeability in the membrane as possible, and electrochemical stability Good performance, good dry-wet conversion performance, certain mechanical strength, good processability. Proton exchange membrane (PEM) is different from the diaphragm used in general chemical power sources. It is recommended to use perfluorosulfonic acid type proton exchange membrane, Nafion recast membrane, non-fluoropolymer proton exchange membrane, new composite proton exchange membrane, etc. In the present invention, the cathode and the anode are separated by PEM, so as to avoid direct electron transmission between the anode and the cathode.

In the lead grid-based water splitting hydrogen production device of the present invention, the DC power interface 4 generates a DC voltage of 1.5 V-5 V.

The anode structure is shown in Figure 2. The anode is made of mesh material, preferably lead metal, alloy or composite metal mesh plated with other materials (such as platinum, titanium, zinc oxide, titanium oxide, etc.) (as shown in Figure 2). The size of the pole piece is positively correlated with the hydrogen demand, that is, the larger the pole piece is, the more hydrogen can be produced under the same voltage/current per unit time. During the working process, the electrons in the electrolyte flow into the power supply through the electrode, and oxygen is generated on the surface of the electrode. The microscopic part of the anode is preferably a layered structure with lead oxide sheets grown in situ (as shown in Figure 2 below). On the one hand, the grid morphology increases the electrochemical reaction area, which is beneficial to the preparation of gas; on the other hand, the pores are conducive to the diffusion of gas.

In the cathode structure shown in Figure 3-1, the main active material of the cathode is platinum metal. The cathode structure can preferably be grid-like, as shown in Figure 3-1, platinum metal is plated on lead grid, titanium grid or alloy grid. On the one hand, this grid shape increases the electrochemical reaction area, which is conducive to the preparation of gas. ; On the other hand, the channel is conducive to the diffusion of gas. Platinum carbon powder catalyst can also be hot pressed on PEM (Proton Exchange Membrane). Through the film-making process shown in Figure 3-2, platinum particles of 2 to 5 nanometers are supported on activated carbon particles of 10 nanometers to 80 nanometers through a platinum-carbon catalyst, which increases the utilization rate of platinum. The size of the pole piece is positively correlated with the hydrogen demand, that is, the larger the pole piece is, the more hydrogen can be produced under the same voltage/current per unit time.

The photo of the anode shown in Figure 4-1 and the scanning electron microscope picture shown in Figure 4-2 show the network structure in Figure 4-1, which is conducive to the removal of gas generated by electrolysis of water, thereby increasing hydrogen production efficiency. The lead oxide flakes on the surface of the lead mesh on the microstructure can be clearly seen, which can greatly increase the area of electrolyzed water and promote the reaction.

From the hydrolysis performance curve of the anode shown in Figure 5, it can be seen that the counter electrode Ag/AgCl is used, the electrolyte is 0.5M sulfuric acid, and the electrode area is 1 cm ² . Figure 6 shows the performance curve of the hydrogen production device at 60°C. The electrolyte is 0.5M sulfuric acid; the anode is a lead grid with an electrode area of 1 cm ² ; the cathode is a platinum sheet with an electrode area of 0.7 cm ² . It can be seen that within 8 hours, hydrogen production The unit operated stably with little noticeable degradation.

The preparation method of the water splitting hydrogen production device based on the lead grid of the present invention.

Step 1, preparing the anode lead grid. Purchase lead foil, and use a punching machine or a laser engraving machine to open holes on the lead foil to prepare a lead grid; or directly purchase the lead grid; the lead grid can be directly used as an anode.

It is also possible to use a sputter coater to coat a layer of nano-platinum on the lead grid and directly use it as an anode.

The lead grid can also be placed in a polytetrafluoroethylene cup filled with concentrated ammonia water, and reacted under high temperature and high pressure at 180°C for 6 hours to 72 hours, and a layer of lead oxide sheet can be grown on the lead grid as an anode.

Step 2, preparing the cathode. A layer of nano-platinum gold was coated on the lead foil with a sputter coater and used as the cathode directly.

Platinum carbon PEM membranes for proton exchange membrane (PEM) fuel cell anodes can also be directly fabricated as cathodes and diaphragms for hydrogen production devices.

In step 3, the proton exchange membrane is interposed between the anode and the cathode, and the above-mentioned anode-diaphragm-cathode is clamped with the shell protective layer and the fixing clip, that is, the water splitting hydrogen production device based on lead mesh is prepared.

A method for using a water splitting hydrogen production device based on lead nets, comprising the following steps.

Step 1, connect the DC power interface 4 to the DC power supply, and connect the anode 1 to the positive pole of the power supply, and connect the cathode 2 to the negative pole of the power supply.

Step 2, place the water splitting hydrogen production device based on the lead grid in the acidic aqueous solution, set the DC power interface 4 on the liquid surface, and avoid the contact between the circuit and the aqueous solution.

Step 3. Turn on the power switch, slowly increase the voltage from 2 V, and adjust to an appropriate voltage according to the hydrogen demand. If the hydrogen demand is large, the voltage will be high, and if the hydrogen demand is small, the voltage will be low.

Step 4, after the gas preparation is completed, first adjust the DC power supply to a low voltage, then turn off the DC power supply, and finally disconnect the DC power supply interface 4 from the DC power supply.

The design of the water splitting hydrogen production device based on the lead grid of the present invention, and the device can operate stably in acid at high temperature without obvious decline; the present invention can be applied to electrocatalytic water splitting hydrogen production system; fuel cell system; electrocatalytic preparation Chlorine gas; catalytic oxidation of small organic molecules. It should also be noted that the shapes and sizes of the components in the drawings do not reflect the actual sizes and proportions, but only illustrate the content of the embodiments of the present invention.

Parts not described in detail in the present invention belong to the known techniques of those skilled in the art. The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (7)

1. A water splitting hydrogen production device based on a lead grid, which includes an anode, a cathode and a diaphragm, is characterized in that it uses a lead grid covered with lead oxide flakes as an anode, and uses a platinum-plated lead grid or a titanium grid or an alloy grid as an anode. For the cathode, a proton exchange membrane (PEM) is used as the separator. 2. The water splitting hydrogen production device based on lead grid according to claim 1, characterized in that: the anode, the diaphragm and the cathode are sequentially stacked to form the main body of the water splitting hydrogen production device. 3. The water splitting hydrogen production device based on lead grid according to claim 2, characterized in that: the extension section of the anode and the extension section of the cathode are respectively provided with a DC power interface; The power supply interface is connected to the water splitting hydrogen production device based on the lead grid. The electrons flowing out of the negative electrode of the power supply flow into the electrolyte through the cathode, and at the same time, a reduction reaction occurs on the surface of the cathode. The hydrogen ions in the electrolyte near the cathode get electrons to generate hydrogen. 4. The water splitting hydrogen production device based on lead grid according to claim 3, characterized in that: the proton exchange membrane (PEM) is perfluorosulfonic acid type proton exchange membrane, Nafion recast membrane, non-fluoropolymer proton exchange Membranes or new composite proton exchange membranes. 5. A preparation method of a lead net-based water splitting hydrogen production device, characterized in that the method comprises the following steps: Step 1, prepare the anode lead grid; use a sputter coater to coat a layer of nano-platinum on the lead grid and use it directly as an anode; or put the lead grid in a polytetrafluoroethylene cup filled with concentrated ammonia water, and react under high temperature and high pressure at 180°C From 6 hours to 72 hours, grow a layer of lead oxide sheet on the lead grid as an anode; Step 2, prepare the cathode, and use a sputter coater to coat a layer of nano-platinum gold on the lead foil directly as the cathode; In step 3, the proton exchange membrane is interposed between the anode and the cathode, and the above anode-diaphragm-cathode is clamped with the shell protective layer and the fixing clip, and a water splitting hydrogen production device based on lead mesh is prepared. 6. The preparation method according to claim 5, characterized in that: The step 2 directly manufactures the platinum carbon PEM membrane for the anode of the proton exchange membrane (PEM) fuel cell as the cathode and the diaphragm of the hydrogen production device. 7. A method for using the lead grid-based water splitting hydrogen production device according to any one of claims 1-4, comprising the following steps: Step 1, connect the DC power interface to the DC power supply, and connect the anode to the positive pole of the DC power supply, and connect the cathode to the negative pole of the DC power supply; Step 2, placing the water splitting hydrogen production device based on the lead grid in the acidic aqueous solution, setting the DC power interface on the liquid surface, and avoiding the contact between the circuit and the aqueous solution; Step 3. Turn on the power switch, slowly increase the voltage from 2 V, and adjust to an appropriate voltage according to the hydrogen demand. If the hydrogen demand is large, the voltage will be high, and if the hydrogen demand is small, the voltage will be low; Step 4: After the gas preparation is completed, first adjust the DC power supply to a low voltage, then turn off the DC power supply, and finally disconnect the DC power supply interface from the DC power supply.