Preparation method of hydrogen production microchannel based on asymmetric wettability gradient and efficient gas-liquid separation

Abstract

The invention discloses a preparation method of a hydrogen production microchannel based on asymmetric wettability gradient and efficient gas-liquid separation, and relates to the technical field of new energy microfluids. The invention aims to solve the technical problem that hydrogen production by electrolyzing water is difficult to realize in the existing microchannel and microgravity environment. According to the method, a micro-channel and a micro-pore channel are prepared by utilizing a surface projection-based micro-stereolithography 3D printing technology, and the micro-pore surface interface of the micro-channel is treated to form an asymmetric wettability interface with a super-hydrophobic top and a hydrophilic bottom of the micro-pore channel. The obtained micro-channel has excellent gas-liquid separation performance and exerts excellent performance in micro-channel electrolytic hydrogen production and microgravity gas-liquid separation application, the process is simple, and operability is high. The hydrogen production microchannel based on asymmetric wettability gradient and efficient gas-liquid separation prepared by the invention is used for producing hydrogen by electrolyzing water.

Description

Technical Field

[0001] The invention relates to the technical field of new energy microfluids, and in particular to a method for preparing a hydrogen production microchannel based on an asymmetric wettability gradient and efficient gas-liquid separation. Background Art

[0002] Hydrogen is known as the "cleanest energy in the world". It has the advantages of high efficiency, no pollution, and renewable. It can be obtained through simple electrolysis. However, in the process of water electrolysis, it is usually strongly affected by the shedding of electrode bubbles caused by buoyancy, which reduces the performance of the electrolysis system in harsh environments such as space, and ultimately leads to poor electrocatalytic activity and stability. Therefore, how to effectively control the generation of bubbles on the electrode surface in extreme environments such as microgravity, thereby accelerating the ion transmission of the electrolysis environment and improving the efficiency of hydrogen production by water electrolysis, has become a key issue in the development of hydrogen production by water electrolysis in extreme environments. The existing microchannel hydrogen production technology mainly focuses on microchannel pressure regulation for bubble control, microchannel design to improve bubble behavior and electromagnetic field non-contact regulation. During the electromagnetic field regulation process, the water electrolysis hydrogen production reaction will be disturbed, and it is difficult to maintain the optimal stable state of water electrolysis hydrogen production, which reduces the reaction efficiency and affects the collection of products. The design improvement and pressure regulation of the microchannel are essentially to regulate the generation and flow of water electrolysis products, and the bubbles need to flow out through the microchannel. This process occupies the microchannel catalytic area and active sites, hindering ion transmission. The difference is that one is the pressure regulation of the microchannel system, which can control the solubility of hydrogen, but the pressure needs to be precisely controlled to avoid excessively high or low pressures that lead to bubble control failure. The microchannel design needs to precisely control the generation rate and distribution of bubbles to avoid bubble aggregation. However, the occupation of microchannels by these two gas control methods will affect the occurrence of the water electrolysis hydrogen production reaction itself, reducing the electrolysis efficiency and bubble control efficiency. Summary of the invention

[0003] In order to solve the technical problem that it is difficult to produce hydrogen by electrolysis of water in existing microchannels and microgravity environments, the present invention provides a method for preparing a hydrogen production microchannel based on an asymmetric wettability gradient and efficient gas-liquid separation.

[0004] A method for preparing a hydrogen production microchannel based on an asymmetric wettability gradient and efficient gas-liquid separation is specifically carried out in the following steps:

[0005] Step 1: Use 3D modeling software to establish a 3D model of a hydrogen production microchannel based on an asymmetric wettability gradient and efficient gas-liquid separation, wherein the hydrogen production microchannel based on an asymmetric wettability gradient and efficient gas-liquid separation consists of a microchannel and a microporous channel;

[0006] The cross section of the microchannel is circular or polygonal, and the microporous channel is a circular through hole or a polygonal through hole;

[0007] Step 2: Use corresponding slicing software to perform image processing on the three-dimensional model in step 1, and transfer the sliced ​​model to the control system of the light-curing 3D printer;

[0008] Step 3: Print layer by layer using a light-curing 3D printer to obtain microchannels and microporous channels;

[0009] Step 4: Using a 405nm ultraviolet lamp to illuminate the microchannel and microporous channel obtained in step 3;

[0010] Step 5: smoothly attach the copper catalyst layer to the bottom of the microchannel processed in step 4 to obtain a microchannel with the copper catalyst layer attached;

[0011] Step 6, immersing the microporous channel treated in step 4 in a hydrochloric acid solution and performing ultrasonic oscillation;

[0012] Step 7, cleaning the microporous channel processed in step 6, and then drying;

[0013] Step 8, fixing the microporous channel cleaned in step 7 on a glass slide, and then spraying a hydrophobic material whose main component is nano-silicon dioxide particles evenly on the upper surface and side walls of the microporous channel;

[0014] The particle size of nano silicon dioxide particles is 20-100nm; the spraying thickness is 500nm-1000nm;

[0015] Step nine, drying the microporous channel processed in step eight to obtain a microporous channel with an asymmetric wettability gradient;

[0016] Step 10. Assemble the microchannel with the copper catalyst layer attached obtained in step 5 and the microporous channel with the asymmetric wettability gradient obtained in step 9. The microporous channel with the asymmetric wettability gradient is assembled on the copper catalyst layer side of the microchannel with the copper catalyst layer attached to obtain a hydrogen production microchannel based on asymmetric wettability gradient and efficient gas-liquid separation.

[0017] The hydrogen production microchannel proposed by the present invention can realize the ultra-fast unidirectional separation and transportation of gas from bottom to top at any position of the microchannel. During the process of transporting bubbles, they do not flow in the microchannel, do not occupy the microchannel, and do not block the catalytic active sites. The core technical principle based on asymmetric wettability gradient and efficient gas-liquid separation is embodied in: at a certain flow rate, the catalyst adhering to the bottom of the microchannel undergoes a reduction reaction to generate hydrogen bubbles, and the top of the microchannel adopts a microporous channel with a uniform array distribution. The microporous channel is modified with asymmetric wettability (super hydrophobic on the top and hydrophilic on the bottom). The bubbles in the vertical direction of the microchannel produce Laplace pressure difference due to the presence of gas-liquid-solid three-phases. Under the joint action of the combined force and Laplace pressure difference, the bubbles can achieve efficient separation within 40ms. After the bubble separation, the catalytic active interface is quickly restored, and the hydrogen production reaction can continue to be carried out continuously and stably.

[0018] The present invention discloses a method for preparing a hydrogen production microchannel based on an asymmetric wettability gradient and efficient gas-liquid separation, comprising a hydrogen production microchannel, wherein the hydrogen production microchannel may be in a circular, rectangular, inverted triangular or other cross-sectional shape, and the top of the hydrogen production microchannel is equipped with a microporous channel, wherein the microporous channel may be in a rectangular, circular, triangular, pentagonal or other polygonal through hole. A copper catalytic layer is provided at the bottom of the hydrogen production microchannel, and the wettability of the inner side of the microporous channel needs to be hydrophilic, and the outer side needs to be super-hydrophobic. The hydrogen production microchannel with an asymmetric wettability gradient and efficient gas-liquid separation of the present invention forms a Laplace pressure difference due to the difference in wettability of the inner and outer sides, and can transport hydrogen produced by electrolysis of water inside the microchannel from the hydrophilic side to the super-hydrophobic side without power and at an ultra-fast rate.

[0019] The hydrogen production microchannel based on asymmetric wettability gradient and efficient gas-liquid separation is used as a flowing electrolysis system. A copper catalyst layer is adhered to the bottom of the microchannel, and the top is a microporous channel based on an asymmetric wettability gradient. The microporous channel is modified with asymmetric wettability (super hydrophobic on the top and hydrophilic on the bottom). The electrolyte flows at a certain speed in the microchannel to provide a channel and environment for ion exchange, and the electrolyte flow rate needs to be controlled within a range that cannot drive the flow of hydrogen bubbles generated on the surface of the catalyst layer. After power is turned on, in a three-electrode electrolysis system, hydrogen bubbles are generated and aggregated on the surface of the copper catalyst layer at the bottom of the microchannel. When the volume of the hydrogen bubbles expands to contact the asymmetric wettability microporous channel at the top, accompanied by the combined effect of the generated Laplace pressure difference and the resultant force, the bubbles will be quickly adsorbed from the bottom of the microchannel electrode to the top of the microporous channel in an ultra-fast unidirectional manner, thereby completing the transport of hydrogen bubbles.

[0020] Beneficial effects of the technical solution of the present invention:

[0021] 1. The hydrogen production microchannel based on asymmetric wettability gradient and efficient gas-liquid separation exhibits excellent performance in controlling bubbles generated on the electrode surface to accelerate ion transport in the electrolysis environment and improve the efficiency of hydrogen production by electrolysis of water, and has long-term stability;

[0022] Second, the hydrogen production microchannel based on asymmetric wettability gradient and efficient gas-liquid separation can achieve ultra-fast unidirectional separation of bubbles within 40ms;

[0023] 3. Nano-silicon dioxide particles are evenly distributed on the top and side walls of the microporous channel to enhance the hydrophobicity of the top and side walls of the channel, which can accelerate the transport efficiency of air columns and bubbles;

[0024] 4. After the asymmetric wettability treatment of the microporous channel shown in the figure, an air film is formed on the top of the micropore, and the inside of the micropore is filled with gas, so that a Laplace pressure difference is formed at the three-phase interface of gas-liquid-solid, so that the gas can be separated from the inside of the microchannel to the top of the microporous channel ultra-fast;

[0025] 5. The hydrogen production microchannel based on asymmetric wettability gradient and efficient gas-liquid separation has a simple structure. The cross-sectional shape of the hydrogen production microchannel can be circular, rectangular, inverted triangle, etc., and the microporous channel can be a polygonal through hole such as rectangular, circular, triangular, pentagonal, etc., which is easy to process and shape.

[0026] The hydrogen production microchannel based on asymmetric wettability gradient and high-efficiency gas-liquid separation prepared by the present invention is used for producing hydrogen by electrolyzing water. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a three-dimensional structural diagram of a hydrogen production microchannel based on an asymmetric wettability gradient and efficient gas-liquid separation as described in the embodiment; 1 is a microporous channel, and 2 is a microchannel;

[0028] Figure 2 for Figure 1 Magnified view; 1 is a microporous channel, 2 is a microchannel;

[0029] Figure 3 The assembly diagram of the microchannel with copper catalyst layer attached to the embodiment and the asymmetric wettability microporous channel, wherein a is the microporous channel (including the microchannel sidewall), b is the bottom of the microchannel (including the copper foil catalyst layer), and c is the assembled device diagram;

[0030] Figure 4 1 is a comparison diagram of the microporous channel in the hydrogen production microchannel based on asymmetric wettability gradient and efficient gas-liquid separation described in the embodiment and the microporous channel in the control example; 1 is a microporous channel;

[0031] Figure 5 1 is an electron microscope image of the microporous channel of the control example; 2 is a microporous channel;

[0032] Figure 6 1 is an electron microscope image of a microporous channel in a hydrogen production microchannel based on an asymmetric wettability gradient and efficient gas-liquid separation as described in the embodiment; 1 is a microporous channel;

[0033] Figure 7 This is an electron microscope image of a microporous channel sprayed with a hydrophobic material in an embodiment;

[0034] Figure 8 This is a diagram of the gas-liquid separation process of the microchannel when the hydrogen production microchannel based on the asymmetric wettability gradient and efficient gas-liquid separation described in the embodiment is in operation;

[0035] Fig. 9 This is an experimental diagram of the movement of hydrogen bubbles produced by electrolyzing water in the microchannel from the hydrophilic side of the microporous channel to the superhydrophobic side when the hydrogen production microchannel based on the asymmetric wettability gradient and efficient gas-liquid separation described in the embodiment is in operation;

[0036] Fig.10 It is the current-time curve diagram of the embodiment and the comparative example. DETAILED DESCRIPTION

[0037] Specific implementation method 1: This implementation method is a method for preparing a hydrogen production microchannel based on asymmetric wettability gradient and efficient gas-liquid separation, which is specifically carried out in the following steps:

[0038] Step 1: Use 3D modeling software to establish a 3D model of a hydrogen production microchannel based on an asymmetric wettability gradient and efficient gas-liquid separation, wherein the hydrogen production microchannel based on an asymmetric wettability gradient and efficient gas-liquid separation consists of a microchannel and a microporous channel;

[0039] The cross section of the microchannel is circular or polygonal, and the microporous channel is a circular through hole or a polygonal through hole;

[0040] Step 2: Use corresponding slicing software to perform image processing on the three-dimensional model in step 1, and transfer the sliced ​​model to the control system of the light-curing 3D printer;

[0041] Step 3: Print layer by layer using a light-curing 3D printer to obtain microchannels and microporous channels;

[0042] Step 4: Using a 405nm ultraviolet lamp to illuminate the microchannel and microporous channel obtained in step 3;

[0043] Step 5: smoothly attach the copper catalyst layer to the bottom of the microchannel processed in step 4 to obtain a microchannel with the copper catalyst layer attached;

[0044] Step 6, immersing the microporous channel treated in step 4 in a hydrochloric acid solution and performing ultrasonic oscillation;

[0045] Step 7, cleaning the microporous channel processed in step 6, and then drying;

[0046] Step 8, fixing the microporous channel cleaned in step 7 on a glass slide, and then spraying a hydrophobic material whose main component is nano-silicon dioxide particles evenly on the upper surface and side walls of the microporous channel;

[0047] The particle size of nano silicon dioxide particles is 20-100nm; the spraying thickness is 500nm-1000nm;

[0048] Step nine, drying the microporous channel processed in step eight to obtain a microporous channel with an asymmetric wettability gradient;

[0049] Step 10. Assemble the microchannel with the copper catalyst layer attached obtained in step 5 and the microporous channel with the asymmetric wettability gradient obtained in step 9. The microporous channel with the asymmetric wettability gradient is assembled on the copper catalyst layer side of the microchannel with the copper catalyst layer attached to obtain a hydrogen production microchannel based on asymmetric wettability gradient and efficient gas-liquid separation.

[0050] Specific implementation method 2: This implementation method is different from the specific implementation method 1 in that: when the cross section of the microchannel in step 1 is a polygon, it includes a rectangle or an inverted triangle. The rest is the same as the specific implementation method 1.

[0051] Specific embodiment 3: This embodiment differs from specific embodiment 1 or 2 in that: when the microporous channel in step 1 is a polygonal through hole, the shape of the polygonal through hole includes a rectangle, a triangle or a pentagon. The rest is the same as specific embodiment 1 or 2.

[0052] Specific embodiment 4: This embodiment differs from specific embodiments 1 to 3 in that the interval between the bottom end of the microchannel and the bottom end of the microporous channel in step 1 is 200 micrometers to 1000 micrometers. The rest is the same as specific embodiments 1 to 3.

[0053] Specific implementation mode 5: This implementation mode is different from specific implementation modes 1 to 4 in that: the diameter of the circumscribed circle of the microchannel cross section in step 1 is 100 micrometers to 1000 micrometers. The rest is the same as specific implementation modes 1 to 4.

[0054] Specific embodiment 6: This embodiment differs from specific embodiments 1 to 5 in that the circumscribed circle of the through hole diameter of the microporous channel in step 1 is 100 micrometers to 1000 micrometers. The rest is the same as specific embodiments 1 to 5.

[0055] Specific embodiment 7: This embodiment differs from specific embodiments 1 to 6 in that the through-hole interval of the microporous channel in step 1 is 50 micrometers to 300 micrometers. The rest is the same as specific embodiments 1 to 6.

[0056] Specific implementation eight: This implementation differs from specific implementations one to seven in that the illumination treatment time in step four is 3 to 5 minutes. The rest is the same as specific implementations one to seven.

[0057] Specific embodiment 9: This embodiment differs from specific embodiments 1 to 8 in that the pasting material used for smoothly pasting the copper catalyst layer in step 5 is a double-sided conductive copper foil tape. The rest is the same as specific embodiments 1 to 8.

[0058] Specific embodiment 10: This embodiment differs from specific embodiments 1 to 9 in that the concentration of the hydrochloric acid solution in step 6 is 0.1 mol / L, the ultrasonic frequency is 40 KHz, and the ultrasonic time is 5 min. The rest is the same as specific embodiments 1 to 9.

[0059] The content of the present invention is not limited to the content of the above-mentioned embodiments. The combination of one or several specific embodiments can also achieve the purpose of the invention.

[0060] Example:

[0061] A method for preparing a hydrogen production microchannel based on an asymmetric wettability gradient and efficient gas-liquid separation is specifically carried out in the following steps:

[0062] Step 1: Use 3D modeling software to establish a 3D model of a hydrogen production microchannel based on an asymmetric wettability gradient and efficient gas-liquid separation, wherein the hydrogen production microchannel based on an asymmetric wettability gradient and efficient gas-liquid separation consists of a microchannel and a microporous channel;

[0063] The cross section of the microchannel is rectangular, and the microporous channel is a rectangular through hole;

[0064] Step 2: Use corresponding slicing software to perform image processing on the three-dimensional model in step 1, and transfer the sliced ​​model to the control system of the light-curing 3D printer;

[0065] Step 3: Use a light-curing 3D printer to print layer by layer to obtain microchannels and microporous channels; the material of the printing material is a polymer light-curing resin; the polymer light-curing resin is purchased from Chongqing Mofang Precision Technology Co., Ltd., and the model is HTL (high temperature resistant resin);

[0066] Step 4: Use a 405nm ultraviolet lamp to illuminate the microchannel and microporous channel obtained in step 3; the illumination time is 5 minutes;

[0067] Step 5: smoothly paste the copper catalyst layer on the bottom of the microchannel processed in step 4 to obtain a microchannel with the copper catalyst layer pasted; the pasting material is a double-sided conductive copper foil tape;

[0068] Step 6: Immerse the microporous channel treated in step 4 in a hydrochloric acid solution and perform ultrasonic oscillation; the concentration of the hydrochloric acid solution is 0.1 mol / L, the ultrasonic frequency is 40 KHz, and the ultrasonic time is 5 min;

[0069] Step 7: Use 25°C deionized water to clean the microporous channels treated in step 6 for 5 minutes, and then dry them at a drying temperature of 60°C for 1 hour;

[0070] Step 8, fix the microporous channel cleaned in step 7 on a glass slide, and then use a hydrophobic material whose main component is nano-silicon dioxide particles to evenly spray the upper surface and side walls of the microporous channel; the hydrophobic material whose main component is nano-silicon dioxide particles is NeverWet produced by Rust-Oleum;

[0071] The particle size of nano silicon dioxide particles is 20 to 100 nm; the spraying thickness is 500 nm to 800 nm;

[0072] Step 9, drying the microporous channel treated in step 8 to obtain an asymmetric wettable microporous channel; the drying temperature is 60° C. and the time is 12 hours;

[0073] Step 10. Assemble the microchannel with copper catalyst layer attached obtained in step 5 and the asymmetric wettability microporous channel obtained in step 9. The asymmetric wettability microporous channel is assembled on the copper catalyst layer side of the microchannel with copper catalyst layer attached. The microporous channel is nested on the top of the microchannel and distributed in a uniform array. The microporous channel is connected to the inside of the microchannel to obtain a hydrogen production microchannel based on asymmetric wettability gradient and efficient gas-liquid separation.

[0074] The diameter of the circumscribed circle of the microchannel cross section in step 1 is 400 microns.

[0075] The circumscribed circle of the through-hole diameter of the microporous channel in step 1 is 400 microns.

[0076] The through-hole spacing of the microporous channel in step 1 is 150 microns.

[0077] In step 1, the interval between the bottom end of the microchannel and the bottom end of the microporous channel is 400 microns.

[0078] The wettability of the inner side of the microporous channel of the gas-liquid separation hydrogen production microchannel structure needs to be hydrophilic, and the outer side needs to be super hydrophobic.

[0079] When the hydrogen production microchannel structure is working, the electrolyte can be injected into the injection port of the microchannel by using a micro-injection pump. After power is turned on, the water electrolysis hydrogen production reaction is activated, and hydrogen bubbles are generated at the bottom of the microchannel 1. As the volume of the bubbles increases, when the bubbles contact the microporous channel 2 assembled above, the hydrogen bubbles, under the action of the Laplace pressure difference, ultra-fast passage from the hydrophilic side at the bottom of the microporous channel 2 to the super-hydrophobic side at the top. This alleviates the catalytic dead zone on the catalyst surface in the microchannel and accelerates the electrolysis reaction.

[0080] Comparative Example: The difference between this comparative example and the embodiment is that the microporous channel is not sprayed with nano-silicon dioxide particles. The other steps and parameters are the same as those of the embodiment.

[0081] Figure 1 This is a three-dimensional structural diagram of a hydrogen production microchannel based on an asymmetric wettability gradient and efficient gas-liquid separation as described in the embodiment; 1 is a microporous channel, and 2 is a microchannel;

[0082] Figure 2 for Figure 1 Magnified view; 1 is a microporous channel, 2 is a microchannel;

[0083] Figure 3 The assembly diagram of the microchannel with copper catalyst layer attached to the embodiment and the asymmetric wettability microporous channel, wherein a is the microporous channel (including the microchannel sidewall), b is the bottom of the microchannel (including the copper foil catalyst layer), and c is the assembled device diagram;

[0084] Figure 4 1 is a comparison diagram of the microporous channel in the hydrogen production microchannel based on asymmetric wettability gradient and efficient gas-liquid separation described in the embodiment and the microporous channel in the control example; 1 is a microporous channel;

[0085] Figure 5 1 is an electron microscope image of the microporous channel of the control example; 2 is a microporous channel;

[0086] Figure 6 1 is an electron microscope image of a microporous channel in a hydrogen production microchannel based on an asymmetric wettability gradient and efficient gas-liquid separation as described in the embodiment; 1 is a microporous channel;

[0087] Figure 7 This is an electron microscope image of a microporous channel sprayed with a hydrophobic material in an example; it can be seen that nano-silicon dioxide particles are attached to the surface of the microporous channel, and the particle size thereof varies from 20 to 100 nm.

[0088] Figure 8The microchannel gas-liquid separation process is shown when the hydrogen production microchannel based on asymmetric wettability gradient and efficient gas-liquid separation as described in the embodiment is in operation; the three figures show that the gas column in the channel will be captured and controlled by the microporous channel when it reaches the bottom of the microporous channel with asymmetric wettability, and finally the entire gas column will be unidirectionally controlled by the microporous channel only outside the microchannel.

[0089] Fig. 9 The hydrogen production microchannel based on asymmetric wettability gradient and efficient gas-liquid separation is operated as described in the embodiment, and the hydrogen bubbles produced by the electrolysis of water in the microchannel move from the hydrophilic side of the microporous channel to the super-hydrophobic side. It is observed from the figure that the electrolyte is injected into the microchannel at a certain flow rate (the flow rate of the electrolyte needs to be controlled small enough to not wash away the bubbles generated on the electrode surface). After the electrolysis reaction starts, bubbles are generated on the bottom copper foil, and the volume gradually expands. After contacting the bottom of the microporous channel, the bubbles are unidirectionally controlled by the microporous channel under the combined action of the Laplace pressure difference and the resultant force, and gather at the top of the microporous channel.

[0090] Fig.10 The current-time curve diagram of the embodiment and the control example; the influence of bubbles on the hydrogen production reaction by electrolysis of water can be obtained from the diagram.

[0091] From the above tests, it can be seen that the microchannel modified with nano-silica particles has the performance of electrolyzing water to produce hydrogen, transport hydrogen, and collect hydrogen. It also has long-term stability, no current density attenuation, and stable performance.

Claims

1. A method for preparing a hydrogen production microchannel based on asymmetric wettability gradient and efficient gas-liquid separation, characterized in that The method is specifically carried out in the following steps: Step 1: Use 3D modeling software to establish a 3D model of a hydrogen production microchannel based on an asymmetric wettability gradient and efficient gas-liquid separation, wherein the hydrogen production microchannel based on an asymmetric wettability gradient and efficient gas-liquid separation consists of a microchannel and a microporous channel; The cross section of the microchannel is circular or polygonal, and the microporous channel is a circular through hole or a polygonal through hole; Step 2: Use corresponding slicing software to perform image processing on the three-dimensional model in step 1, and transfer the sliced ​​model to the control system of the light-curing 3D printer; Step 3: Print layer by layer using a light-curing 3D printer to obtain microchannels and microporous channels; Step 4: Using a 405nm ultraviolet lamp to illuminate the microchannel and microporous channel obtained in step 3; Step 5: smoothly attach the copper catalyst layer to the bottom of the microchannel processed in step 4 to obtain a microchannel with the copper catalyst layer attached; Step 6, immersing the microporous channel treated in step 4 in a hydrochloric acid solution and performing ultrasonic oscillation; Step 7, cleaning the microporous channel processed in step 6, and then drying; Step 8, fixing the microporous channel cleaned in step 7 on a glass slide, and then spraying a hydrophobic material whose main component is nano-silicon dioxide particles evenly on the upper surface and side walls of the microporous channel; The particle size of nano silicon dioxide particles is 20-100nm; the spraying thickness is 500nm-1000nm; Step nine, drying the microporous channel processed in step eight to obtain a microporous channel with an asymmetric wettability gradient; Step 10. Assemble the microchannel with the copper catalyst layer attached obtained in step 5 and the microporous channel with the asymmetric wettability gradient obtained in step 9. The microporous channel with the asymmetric wettability gradient is assembled on the copper catalyst layer side of the microchannel with the copper catalyst layer attached to obtain a hydrogen production microchannel based on asymmetric wettability gradient and efficient gas-liquid separation.

2. The method for preparing a hydrogen production microchannel based on asymmetric wettability gradient and efficient gas-liquid separation according to claim 1, characterized in that When the cross section of the microchannel in step 1 is polygonal, it includes a rectangle or an inverted triangle.

3. The method for preparing a hydrogen production microchannel based on asymmetric wettability gradient and efficient gas-liquid separation according to claim 1, characterized in that When the microporous channel in step 1 is a polygonal through hole, the shape of the polygonal through hole includes a rectangle, a triangle or a pentagon.

4. The method for preparing a hydrogen production microchannel based on asymmetric wettability gradient and efficient gas-liquid separation according to claim 1, characterized in that In step 1, the diameter of the circumscribed circle of the microchannel cross section is 100 microns to 1000 microns.

5. The method for preparing a hydrogen production microchannel based on asymmetric wettability gradient and efficient gas-liquid separation according to claim 1, characterized in that In step 1, the circumscribed circle of the through-hole diameter of the microporous channel is 100 microns to 1000 microns.

6. The method for preparing a hydrogen production microchannel based on asymmetric wettability gradient and efficient gas-liquid separation according to claim 1, characterized in that In step 1, the through-hole spacing of the microporous channel is 50 microns to 300 microns.

7. The method for preparing a hydrogen production microchannel based on asymmetric wettability gradient and efficient gas-liquid separation according to claim 1, characterized in that In step 1, the interval between the bottom end of the microchannel and the bottom end of the microporous channel is 200 microns to 1000 microns.

8. The method for preparing a hydrogen production microchannel based on asymmetric wettability gradient and efficient gas-liquid separation according to claim 1, characterized in that The illumination treatment time in step 4 is 3 to 5 minutes.

9. The method for preparing a hydrogen production microchannel based on asymmetric wettability gradient and efficient gas-liquid separation according to claim 1, characterized in that Step 5: Smoothly paste the copper catalyst layer using a double-sided conductive copper foil tape.

10. The method for preparing a hydrogen production microchannel based on asymmetric wettability gradient and efficient gas-liquid separation according to claim 1, characterized in that In step 6, the concentration of the hydrochloric acid solution is 0.1 mol / L, the ultrasonic frequency is 40 KHz, and the ultrasonic time is 5 min.

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