CN112516936B

CN112516936B - Thermoelectric coupling micro flow reactor and preparation method thereof

Info

Publication number: CN112516936B
Application number: CN202011501014.3A
Authority: CN
Inventors: 廖洪钢; 孙悦; 江友红
Original assignee: Xiamen University
Current assignee: Xiamen University
Priority date: 2020-12-18
Filing date: 2020-12-18
Publication date: 2022-02-08
Anticipated expiration: 2040-12-18
Also published as: CN112516936A

Abstract

The invention discloses a thermocouple micro flow reactor and a preparation method thereof. The upper piece is a silicon substrate with silicon nitride on two sides, and the lower piece is made of a non-conductive light-transmitting material; the upper sheet is provided with a liquid inlet area, a liquid outlet area, a microfluid channel and a nafion membrane; the lower piece is provided with a temperature control system and an electrochemical system which are separated by an insulating layer; the heating and temperature control of the temperature control system are realized by a four-electrode snake-shaped thermal resistor; the electrochemical system comprises an electrode layer and a catalyst layer; the electrode layer is provided with a working electrode, a counter electrode and a reference electrode, and is arranged right above the snake-shaped thermal resistor, the working electrode and the counter electrode are arranged in an array fork-shaped staggered manner, and the reference electrode is independently arranged at one side close to the working electrode and the liquid inlet area; a catalyst layer is attached to the working electrode. The electrode and electrode spacing is small, the reaction liquid layer is thin, the reaction rate is high, the heat transfer and mass transfer rates are high, and the method can be used for researching the coupling influence of electric energy and heat energy on chemical reaction and the reaction mechanism.

Description

Thermoelectric coupling micro flow reactor and preparation method thereof

Technical Field

The invention relates to the field of micro flow reactors, in particular to a thermoelectric coupling micro flow reactor and a preparation method thereof.

Background

In recent years, with the breakthrough development of material science, micro-nano processing technology and microelectronics, micro flow reactors have been proved to be a powerful tool for enhancing electrochemical systems. The micro flow reactor has the advantages of small electrode distance, large electrode specific surface area, uniform current density, direct scale-up without pilot plant test, and the like, and can overcome the mass transfer limitation inherent in the traditional H-shaped cell by continuously circulating reactants and products to the electrodes and far away from the electrodes. In addition, the micro-reactor has extremely high heat transfer efficiency, can quickly realize temperature rise, temperature stabilization and temperature reduction, and can well control high-temperature reaction which is difficult to realize under the conventional condition, but the current examples for researching that the experimental temperature of the micro-flow reactor is higher than an environmental value are few, because the influence of the thermal effect on the reaction is extremely complex, for example, the thermal effect can improve the diffusion coefficient and the reaction activity, and can also lead to lower solubility, therefore, the temperature in the micro-reactor is monitored on site, and the electrochemical reaction under the heating condition is researched, so that the micro-reactor also has good practical significance.

Disclosure of Invention

The invention aims to provide a thermoelectric coupling micro-flow reactor for regulating and controlling electrochemical reaction through the coupling action of electric energy and heat energy. The working electrode and the counter electrode of the reactor are miniature electrodes which are arranged in an array fork shape, the electrode spacing is small, the specific surface area of the electrodes is large, the ohmic drop can be effectively reduced, the mass transfer rate is improved, the stable mass transfer is quickly established, and the uniform and large current density is obtained; the temperature control system is introduced into the reactor, so that the electrochemical system can be well controlled in situ, the heat transfer efficiency is high, the thermal responsiveness is good, the temperature rise and the temperature stabilization can be realized quickly, the product selectivity is improved, and the high-temperature reaction which is difficult to realize under the conventional condition can be well controlled; the reactor is provided with an ultrathin reaction chamber, the amount of reaction liquid for single treatment is uL level, the reaction liquid continuously flows into the chamber to carry out electrochemical reaction and flows out, the conversion from a bulk phase reaction mode to an interface thin layer reaction mode can be realized, and the electrochemical reaction rate and efficiency can be improved; the reactor has good mechanical strength, is not easy to be damaged, can be repeatedly used, can be directly amplified in scale without a pilot plant test, and is beneficial to industrial production. Based on the performance advantages, the thermocouple micro flow reactor can be used for regulating and controlling an electrochemical system with limited mass transfer, slower speed, complex product, high reaction temperature or accurate temperature control under the conventional condition so as to improve the electrochemical reaction performance.

In order to achieve the purpose, the invention provides a thermocouple micro flow reactor, which comprises an upper plate and a lower plate, wherein the upper plate and the lower plate are divided into a front surface and a back surface, the front surface of the upper plate is directly bonded with the front surface of the lower plate through a metal bonding layer, and an ultrathin reaction chamber is formed by self-sealing; the silicon-based LED chip is characterized in that the upper chip is a silicon substrate with silicon nitride on two surfaces, and the lower chip is made of a non-conductive light-transmitting material; the upper sheet is provided with a liquid inlet area, a liquid outlet area, a microfluid channel and a nafion membrane; the liquid inlet area and the liquid outlet area are positioned on two sides of the upper sheet, the microfluidic channel is positioned between the liquid inlet area and the liquid outlet area, the nafion membrane is distributed at the interval of the microfluidic channel, and the back of the upper sheet is provided with a liquid inlet and a liquid outlet which are respectively communicated with the liquid inlet area and the liquid outlet area;

the lower piece is provided with a temperature control system and an electrochemical system which are separated by an insulating layer; the heating and temperature control of the temperature control system are realized by a four-electrode snake-shaped thermal resistor; the electrochemical system comprises an electrode layer and a catalyst layer; the electrode layer is provided with a working electrode, a counter electrode and a reference electrode, and is arranged right above the snake-shaped thermal resistor, the working electrode and the counter electrode are arranged in an array fork-shaped staggered manner, and the reference electrode is independently arranged on one side close to the working electrode and the liquid inlet; the wiring ports of the working electrode, the counter electrode and the reference electrode are positioned at the edge of the long edge of the lower sheet, and the catalyst layer is attached to the working electrode.

The microfluidic channels of the upper sheet and the working electrodes and counter electrodes of the lower sheet are aligned one by one, namely one working electrode or counter electrode is arranged in each channel, and the nafion membrane at the channel interval separates the working electrode area from the counter electrode area.

Further, the outer dimension of the lower sheet is 6 x 10-60 x 100 mm; preferably, the outer dimension of the lower sheet is 30 x 50 mm;

optionally, the metal bonding layer has a thickness of 50nm to 2000 nm; the metal bonding layer is made of high-melting-point metal; preferably, the metal bonding layer is made of Au, Al or Ag;

the thickness of the silicon nitride or the silicon oxide is 100-500 nm;

optionally, the thickness of the silicon substrate is 200-500 μm;

optionally, the thickness of the lower sheet is 500-2000 μm;

optionally, the lower sheet is made of quartz glass.

Further, the liquid inlet or the liquid outlet is round or square; preferably, the liquid inlet or the liquid outlet is square; more preferably, the side length of the square is 0.5mm-1.5 mm; most preferably, the square has a side length of 1.25 mm.

Further, the temperature control system is arranged into two groups of equivalent circuits which are respectively controlled by using a separate current source table and a voltage source table; one loop of the two equivalent circuits is responsible for power supply and heat production, the other loop is responsible for monitoring the resistance value of the heating wire after heating in real time, and the resistance of the test circuit is adjusted in real time through the feedback circuit according to the correlation between the resistance R and the temperature T so as to reach the set temperature.

Furthermore, four contact electrodes of four electrodes of the temperature control system in the lower sheet are arranged at the edge of the short side of the lower sheet, and the snake-shaped thermal resistor is positioned in the center of the lower sheet;

optionally, the width of the heating wire of the serpentine thermal resistor is 0.3-0.9mm, and the thickness of the heating wire is 50nm-500 nm; preferably, the heating wire is made of metal gold, platinum, palladium, rhodium, molybdenum, tungsten, platinum-rhodium alloy or nonmetal molybdenum carbide;

optionally, the metal material of the three electrodes is gold or platinum;

optionally, the working and counter electrode array forked portions are 1cm x 50 μm to 3cm x 200 μm in size, preferably 1.6cm x 100 μm, and 50 to 500nm thick;

furthermore, the insulating layer is a layer of silicon oxide or silicon nitride, and the thickness of the insulating layer is 50-500 nm.

Further, the material of the catalyst layer is Cu, Au, Pt, Zn, Ag, Pd, Ni, Sn or In, and the thickness is 5-200 nm;

further, the preparation method of the upper piece comprises the following steps,

s1, transferring liquid inlet and outlet patterns from a photoetching mask plate to the back of a Si (100) wafer A with silicon nitride or silicon oxide layers on two sides by utilizing a photoetching process, and developing in a positive photoresist developing solution to obtain a wafer A-1;

preferably, the photoetching process is exposure in a hard contact mode of an ultraviolet photoetching machine; the thickness of the silicon nitride or silicon oxide layer is 100-500 nm; the photoresist of the photoetching process is AZ 5214E; the developing time is 40 s; more preferably, the exposure time is 20 s;

optionally, the thickness of the silicon nitride or the silicon oxide is 100-500 nm;

optionally, the thickness of the wafer A is 200-500 μm;

s2, etching a liquid inlet and a liquid outlet on the silicon nitride layer on the back of the wafer A-1 by using a reactive ion etching process, then putting the back of the wafer A-1 upwards into acetone for soaking, and finally washing with a large amount of deionized water to remove photoresist to obtain a wafer A-2;

preferably, the liquid inlet or the liquid outlet is round or square; more preferably, the liquid inlet or the liquid outlet is square; more preferably, the side length of the square is 0.5mm-1.5 mm; most preferably, the sides of the square are 1.25 mm;

s3, placing the wafer A-2 with the back side facing upwards into a potassium hydroxide solution for wet etching until only a thin film window is left on the front side, taking out the wafer A-2, and washing with a large amount of deionized water to obtain a wafer A-3;

preferably, the mass percentage concentration of the potassium hydroxide solution is 20%; the etching temperature is 80 ℃, and the etching time is 4-8 h;

more preferably, the etching time is 6 hours;

s4, a photoetching process, namely transferring the patterns of the microfluid channel, the liquid inlet area and the liquid outlet area from the photoetching mask plate to the front side of the wafer A-3, and developing in positive photoresist developing solution to obtain the wafer A-4;

preferably, the photoetching process is exposure in a hard contact mode of an ultraviolet photoetching machine; the photoresist of the photoetching process is AZ 5214E; the development time was 50 s;

s5, etching the silicon nitride layers on the front micro-fluid channel, the liquid inlet area and the liquid outlet area of the wafer A-4 by utilizing a deep silicon etching process to obtain a wafer A-5;

s6, continuing to etch the silicon on the front side of the wafer A-5 by using a deep silicon etching process to obtain a micro-fluid channel, a liquid inlet area and a liquid outlet area, wherein the etching depth is 5-50 mu m, then placing the wafer A-5 with the front side facing upwards into acetone for soaking, finally washing by using a large amount of deionized water, and removing photoresist to obtain a wafer A-6;

s7, coating nafion films on the micro-channels at intervals to obtain a wafer A-7;

preferably, the thickness of the coating is 50-5000 nm;

and S8, carrying out laser scribing on the wafer A-7, and dividing the wafer A-7 into independent parts to obtain upper pieces.

Further, the preparation method of the lower sheet comprises the following steps,

s1, preparing a non-conductive light-transmitting material B with the size of 6 x 10-60 x 100mm, smooth two surfaces and side walls and the thickness of 0.5-2 mm;

preferably, the non-conductive light-transmitting material is quartz glass; the external dimension of the lower sheet is 30 x 50 mm;

s2, transferring the snakelike thermal heating wire pattern from the photoetching mask plate to the front side of the B by utilizing a photoetching process, developing in a positive photoresist developing solution, and cleaning the surface by using deionized water to obtain B-1;

preferably, the photoetching process is exposure in a hard contact mode of an ultraviolet photoetching machine; the photoresist used in the photoetching process is AZ 5214E; the development time was 50 s;

more preferably, the exposure time is 35 s;

s3, plating a layer of metal on the front side of the B-1 by utilizing magnetron sputtering, then putting the front side of the B-1 upwards into acetone in sequence for soaking and stripping, finally washing with deionized water, removing the photoresist, and leaving a metal heating wire to obtain B-2;

preferably, the metal of the metal heating wire is metal gold, platinum, palladium, rhodium, molybdenum, tungsten, platinum-rhodium alloy or nonmetal molybdenum carbide; the width of the metal heating wire is 0.3-0.9mm, and the thickness of the metal heating wire is 50-500 nm;

s4, growing a layer of silicon nitride or silicon oxide on the metal heating wire of the B-2 by using a PECVD process to serve as an insulating layer to obtain B-3;

preferably, the thickness of the insulating layer is 50-500 nm;

s5, transferring patterns of the working electrode, the counter electrode and the reference electrode from the photoetching mask plate to the front side of the B-3 by utilizing a photoetching process, developing in a positive photoresist developing solution, and cleaning the surface by using deionized water to obtain B-4;

s6, plating a layer of metal on the front side of the B-4 by utilizing magnetron sputtering, then putting the front side of the B-4 upwards into acetone for soaking and stripping, then washing with deionized water, removing the photoresist, and leaving three electrodes to obtain B-5;

preferably, the metal material is gold or platinum; the working and counter electrode array forked portions of the three electrodes are 1cm x 50 μm-3cm x 200 μm in size, preferably 1.6cm x 100 μm; the thickness is 50-500 nm;

s7, transferring the pattern of the catalyst layer from the photoetching mask plate to the front side of the B-5 by utilizing a photoetching process, developing in a positive photoresist developing solution, and cleaning the surface by using deionized water to obtain B-6;

s8, preparing a catalyst on the front side of the B-6 by using a magnetron sputtering method, an electroplating method, an in-situ synthesis method or the like, then placing the B-6 with the front side facing upwards into acetone for soaking and stripping, then washing with deionized water, removing the photoresist, and leaving a catalyst layer to obtain quartz glass B-7;

the catalyst layer is made of Cu, Au, Pt, Zn, Ag, Pd, Ni, Sn or In and has the thickness of 5-200 nm.

Further, the obtained upper plate and the lower plate are assembled under a microscope, so that the microfluidic channels of the upper plate and the working electrodes and counter electrodes of the lower plate are aligned one by one, namely one working electrode or one counter electrode is arranged in each channel.

Drawings

Fig. 1 is a back view of the upper sheet.

Fig. 2 is a front view of the upper sheet.

Fig. 3 is a schematic illustration of the upper plate channel spacing coated with Nafion.

FIG. 4 is a schematic view of a bottom plate temperature control system.

FIG. 5 is a schematic view of a bottom PECVD deposited insulating layer.

FIG. 6 is a schematic diagram of a three-electrode structure formed on a lower substrate.

FIG. 7 is a schematic view of the catalyst supported on the lower plate.

Fig. 8 is a schematic view showing the overall structure.

FIG. 9 is a microreactor schematic.

FIG. 10 is a microreactor cross-sectional view.

FIG. 11 is a diagram of the infrared imaging temperature measurement results after the lower sheet is electrified.

FIG. 12 is a graph showing the results of the thermal responsiveness test in example 3.

FIG. 13 is a graph showing the test results of example 4.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention. The examples do not specify particular techniques or conditions, and are performed according to the techniques or conditions described in the literature in the art or according to the product specifications. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.

The following fabrication of the thermoelectrically coupled micro flow reactor was performed according to the structures of fig. 1 to 10. Wherein 1 is a thermocouple micro flow reactor; 2, loading the plate; 3 is lower slice; 4 is a metal bonding layer; 5 is a liquid inlet area; 6 is a liquid outlet area; 7 is a liquid inlet; 8 is a liquid outlet; 9 is a channel interval; 10 is a microfluidic channel; 11 is a nafion membrane; 12 is an electrode layer, 121 is a counter electrode; 122 is a reference electrode; 123 is a working electrode; 13 is a catalyst layer, 14 is an electrochemical system; 15 is an insulating layer; 16 is a temperature control system; 17 is a silicon substrate; 18 is a silicon nitride or silicon oxide layer.

EXAMPLE 1 preparation of a thermocouple microfluidic reactor

The preparation method of the upper piece comprises the following steps,

optionally, the thickness of the wafer A is 200-500 μm;

the liquid inlet or the liquid outlet is round or square; more preferably, the liquid inlet or the liquid outlet is square; more preferably, the side length of the square is 0.5mm-1.5 mm; most preferably, the sides of the square are 1.25 mm;

more preferably, the etching time is 6 hours;

preferably, the thickness of the coating is 50-5000 nm;

The preparation method of the lower sheet comprises the following steps,

more preferably, the exposure time is 35 s;

preferably, the thickness of the insulating layer is 50-500 nm;

the catalyst layer is made of Cu, Au, Pt, Zn, Ag, Pd, Ni, Sn or In and has the thickness of 5-200 nm;

and assembling the upper sheet and the lower sheet under a microscope to align the microfluid channels of the upper sheet and the working electrodes and the counter electrodes of the lower sheet one by one, namely arranging one working electrode or one counter electrode in each channel.

Example 2

The four contact electrodes of the serpentine thermal resistor on the lower plate of the thermocouple micro-microreactor obtained in example 1 are communicated with an external power controller through leads, and are electrified and heated, and the lower plate is placed in front of a lens of a thermal infrared imager to carry out infrared imaging temperature measurement, and as a result, as shown in fig. 11, when the microreactor is electrified and heated up, the temperature of a serpentine heating wire area is raised to 139.9 ℃, and the temperature of a substrate far away from the heating wire area is still close to room temperature and is 27.9 ℃. And the distribution of the thermal field of the heating area is uniform, which is beneficial to controlling the uniformity of the chemical reaction in the reactor.

Example 3

The four contact electrodes of the serpentine thermal resistor on the lower plate of the thermocouple micro-flow reactor obtained in example 1 are connected with a direct current power supply through leads, and the thermal responsiveness of the reactor is tested. The experiment stipulates that the time required for 95% of the temperature value to reach the target temperature is the thermal phase response time, and the experiment tests the stabilization time at the temperature of 80, 160, 240, 320 and 400 ℃. The results are shown in FIG. 12, which shows that the reactor can be stabilized within several seconds, the time is short, and the thermal responsiveness is good.

Example 4

The thermocouple microreactor obtained in example 1 was used for electrochemical reduction of carbon dioxide, with the catalyst material being copper metal and having a thickness of 20 nm. Will be saturated with CO₂Gaseous 0.1M KHCO₃Introducing the liquid into a reactor, heating the reactor by electrifying, and pressurizing the system to 2MPa by an external pressurizing device, wherein CO is contained in the system₂Heating, pressurizing and reacting in a liquid thin layer, detecting the gas-phase product after reaction by gas chromatography on line, and detecting the liquid-phase product by nuclear magnetic resonance technology, wherein the main C1 and C2 products have the results shown in FIG. 13. It can be seen that the selectivity of the product is different at different temperatures. By using the unconventional research means to adjust the heating temperature of the reactor, CO can be effectively regulated and controlled₂The proportion of products is reduced electrochemically, so that the reaction mechanism is discussed and the selectivity is improved.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made in the above embodiments by those of ordinary skill in the art without departing from the principle and spirit of the present invention.

Claims

1. A thermocouple micro flow reactor comprises an upper plate and a lower plate, wherein the upper plate and the lower plate are divided into a front surface and a back surface, the front surface of the upper plate is directly bonded with the front surface of the lower plate through a metal bonding layer, and an ultrathin reaction chamber is formed by self-sealing; the silicon-based LED chip is characterized in that the upper chip is a silicon substrate with silicon nitride on two surfaces, and the lower chip is made of a non-conductive light-transmitting material; the upper sheet is provided with a liquid inlet area, a liquid outlet area, a microfluid channel and a nafion membrane; the liquid inlet area and the liquid outlet area are positioned on two sides of the upper sheet, the microfluidic channel is positioned between the liquid inlet area and the liquid outlet area, the nafion membrane is distributed at the interval of the microfluidic channel, and the back of the upper sheet is provided with a liquid inlet and a liquid outlet which are respectively communicated with the liquid inlet area and the liquid outlet area;

the lower piece is provided with a temperature control system and an electrochemical system which are separated by an insulating layer; the heating and temperature control of the temperature control system are realized by a four-electrode snake-shaped thermal resistor; the electrochemical system comprises an electrode layer and a catalyst layer; the electrode layer is provided with a working electrode, a counter electrode and a reference electrode, and is arranged right above the snake-shaped thermal resistor, the working electrode and the counter electrode are arranged in an array fork-shaped staggered manner, and the reference electrode is independently arranged on one side close to the working electrode and the liquid inlet; the wiring ports of the working electrode, the counter electrode and the reference electrode are positioned at the edge of the long edge of the lower sheet, and the catalyst layer is attached to the working electrode;

2. The thermoelectric coupled microfluidic reactor of claim 1, wherein said lower plate has an outer dimension of 6 x 10 to 60 x 100 mm.

3. A thermoelectric coupled microfluidic reactor according to claim 2 wherein said lower plate has an outer dimension of 30 x 50 mm.

4. The thermocouple microfluidic reactor of claim 2 wherein said metal bonding layer has a thickness of 50nm to 2000 nm; the material of the metal bonding layer is high-melting-point metal.

5. The thermocouple microfluidic reactor of claim 2 wherein the silicon nitride on the silicon substrate has a thickness of 100-500 nm.

6. The thermocouple microfluidic reactor of claim 2 wherein said silicon substrate has a thickness of 200-500 μm.

7. The thermocouple microfluidic reactor of claim 2 wherein the lower plate has a thickness of 500-2000 μm.

8. A thermoelectric coupling micro-flow reactor as in claim 2 wherein said lower plate is made of quartz glass.

9. A thermocouple microfluidic reactor as claimed in claim 1 wherein said liquid inlet or outlet is circular or square.

10. A thermocouple microfluidic reactor as claimed in claim 9 wherein said fluid inlet or fluid outlet is square.

11. A thermoelectric coupled micro-flow reactor as recited in claim 10, wherein the square has sides of 0.5mm to 1.5 mm.

12. A thermoelectric coupled micro-flow reactor as recited in claim 11, wherein the square has a side of 1.25 mm.

13. A thermoelectric coupled microfluidic reactor as in claim 1 wherein said temperature control system is provided as two sets of equivalent circuits controlled using separate current and voltage source meters, respectively; one loop of the two equivalent circuits is responsible for power supply and heat production, the other loop is responsible for monitoring the resistance value of the heating wire after heating in real time, and the resistance of the test circuit is adjusted in real time through the feedback circuit according to the correlation between the resistance R and the temperature T so as to reach the set temperature.

14. A thermoelectric coupled micro flow reactor as in claim 1 wherein four contact electrodes of the four electrodes of the thermal control system in the lower chip are placed at the short edge of the lower chip and the serpentine shaped thermal resistor is located at the center of the lower chip.

15. A thermocouple microfluidic reactor according to claim 1 wherein the heating wires of said serpentine-shaped thermal resistor have a width of 0.3-0.9mm and a thickness of 50-500 nm.

16. A thermoelectric coupled micro-flow reactor as recited in claim 15, wherein the heating wire is formed of metallic gold, platinum, palladium, rhodium, molybdenum, tungsten, platinum-rhodium alloy, or non-metallic molybdenum carbide.

17. A thermoelectric coupled micro-flow reactor as in claim 15, wherein the metallic material of the three electrodes of the working electrode, the counter electrode and the reference electrode is gold or platinum.

18. The thermoelectric coupled microfluidic reactor of claim 15, wherein the working electrode and counter electrode array prongs are 1cm by 50 μm to 3cm by 200 μm in size.

19. A thermoelectric coupled microfluidic reactor according to claim 18 wherein the working electrode and counter electrode array prongs are 1.6cm x 100 μm in size and 50-500nm thick.

20. A thermoelectric coupled micro-flow reactor as in claim 1, wherein said insulating layer is a layer of silicon oxide or silicon nitride having a thickness of 50-500 nm.

21. The thermoelectric coupled microfluidic reactor of claim 1, wherein said catalyst layer is made of Cu, Au, Pt, Zn, Ag, Pd, Ni, Sn or In and has a thickness of 5-200 nm.

22. A thermoelectric coupling micro-flow reactor as in claim 1 wherein said upper plate is fabricated by a method comprising,

s1, transferring liquid inlet and outlet patterns from a photoetching mask plate to the back of a Si (100) wafer A with silicon nitride on two sides by utilizing a photoetching process, and developing in an orthofilm developing solution to obtain a wafer A-1;

23. The thermocouple microfluidic reactor of claim 22 wherein the photolithography process in step S1 is exposure to light in hard contact mode of an ultraviolet lithography machine; the photoresist of the photoetching process is AZ 5214E; the developing time is 40 s; the exposure time was 20 s; the thickness of the wafer A is 200-500 μm.

24. The thermocouple micro-flow reactor as recited in claim 22 wherein the potassium hydroxide solution is present in a concentration of 20% by mass in step S3; the etching temperature is 80 ℃, and the etching time is 4-8 h.

25. A thermoelectric coupled micro-flow reactor as in claim 24 wherein the etching time is 6 hours.

26. The thermocouple microfluidic reactor of claim 22 wherein the photolithography process in step S4 is exposure to light in hard contact mode of an ultraviolet lithography machine; the photoresist of the photoetching process is AZ 5214E; the development time was 50 s.

27. A thermocouple microfluidic reactor as claimed in claim 22 wherein the nafion membrane coated in step S7 has a thickness of 50-5000 nm.

28. A thermocouple micro-flow reactor according to claim 1, wherein the lower plate is prepared by,

s6, plating a layer of metal on the front side of the B-4 by utilizing magnetron sputtering, wherein the metal is made of gold or platinum, then placing the B-4 with the front side facing upwards into acetone for soaking and stripping, then washing with deionized water, removing the photoresist, and leaving three electrodes, namely a working electrode, a counter electrode and a reference electrode to obtain B-5;

s8, preparing a catalyst on the front side of the B-6 by utilizing a magnetron sputtering or electroplating or in-situ synthesis method, then putting the B-6 with the front side facing upwards into acetone for soaking and stripping, then washing with deionized water, removing the photoresist, and leaving a catalyst layer to obtain quartz glass B-7;

29. A thermocouple microfluidic reactor according to claim 28 wherein the non-conductive light transmissive material is quartz glass; the outer dimension of the lower sheet was 30 x 50 mm.

30. The thermocouple microfluidic reactor of claim 28 wherein the photolithography process in step S2 is exposure to light in hard contact mode of an ultraviolet lithography machine; the photoresist used in the photoetching process is AZ 5214E; the development time was 50s and the exposure time was 35 s.

31. A thermoelectric coupled micro-flow reactor as recited in claim 28, wherein the metal of the metal heater wire is gold, platinum, palladium, rhodium, molybdenum, tungsten, platinum-rhodium alloy; the width of the metal heating wire is 0.3-0.9mm, and the thickness of the metal heating wire is 50-500 nm.

32. The thermocouple microfluidic reactor of claim 28 wherein the photolithography process in step S5 is exposure to light in hard contact mode of an ultraviolet lithography machine; the photoresist used in the photoetching process is AZ 5214E; the development time was 50 s.

33. The thermocouple microfluidic reactor of claim 28 wherein the photolithography process in step S7 is exposure to light in hard contact mode of an ultraviolet lithography machine; the photoresist used in the photoetching process is AZ 5214E; the development time was 50 s.

34. The thermoelectric coupling microfluidic reactor of claim 1, wherein the resulting upper and lower plates are assembled under a microscope such that the microfluidic channels of the upper plate are aligned with the working and counter electrodes of the lower plate, i.e., one working or counter electrode is disposed in each channel.