Ion-electron coupling normal transmission bifunctional photoelectrocatalysis device and preparation method thereof

Abstract

The invention discloses an ion-electron coupling normal transmission bifunctional photoelectrocatalysis device and a preparation method thereof, and belongs to the field of photoelectrocatalysis. The invention aims to solve the problem that the energy conversion efficiency of an existing photoelectrocatalysis system is quickly reduced along with electrode size amplification. According to the invention, the bifunctional photoelectrocatalysis device is constructed, so that the electron and ion flowing mode is changed, and meanwhile, the ion transmission path is optimized. In the photoelectrocatalysis process, catalysts are loaded on the two sides of the conductive substrate in the bifunctional photoelectrocatalysis device, short-distance electron conduction can be carried out in the direction perpendicular to the normal direction of the conductive substrate, and selective directional short-distance ion transmission is achieved while an oxidation-reduction catalysis center is separated; the electrons on the two sides are not transmitted to an external circuit for migration through the surface of the electrode any more, but are transmitted through a normal path of the substrate, so that the amplification loss caused by non-uniformly distributed resistors on the surface of the electrode is overcome.

Description

Technical Field

[0001] This invention belongs to the field of photoelectrocatalysis, specifically relating to a bifunctional photoelectrocatalytic device and its preparation method. Background Technology

[0002] Over the past few decades, the share of renewable energy in global energy supply has increased significantly. However, as the volatility of renewable energy has become increasingly apparent, the focus of development has gradually shifted from power generation technology to energy storage systems. This transformation is evident in the fact that while direct photocatalytic water splitting technology has been a research topic since the 1970s, it has recently become a hot research area again. Progress in this field is not only due to breakthroughs in the development of new photovoltaic materials and catalysts, but also relies on the continuous optimization of multi-junction solar cell designs.

[0003] Despite half a century of research into photoelectrocatalytic systems, such as those for hydrogen production, commercialization remains a long and arduous process, with few large-scale demonstrations. While significant progress has been made in water splitting materials research, current results are still limited to laboratory scale (typically <5 square centimeters). Developing scalable system architectures is crucial for making this technology competitive as a green hydrogen production solution. Notably, in the scaling-up process, the configuration design of the photoelectrode, the structure design of the photoelectrode, and the selection of photocatalytic materials are equally important. Although nanostructured materials have been highly optimized at the laboratory scale, scaling their performance non-destructively to commercial sizes (>1 square meter) remains a major technical challenge.

[0004] The key to achieving large-scale application of photoelectrocatalytic hydrogen production lies in maintaining its efficiency in small systems on a large engineering scale. However, existing research shows that directly scaling up the photoelectrode size and correspondingly increasing the cross-sectional area in a photoelectrocatalytic system leads to a significant degradation in photoelectrocatalytic performance. For unbiased photoelectrocatalytic systems, taking the typical photoanode BiVO4 / BiOI reported in the literature as an example, the performance degradation is as high as 60-70% when the system size is scaled up from 0.45 square centimeters to 3 square centimeters. In the TiO2 / CdS photoanode system actually built in the laboratory, the performance degradation can reach more than 83% when the system size is scaled up from 0.5 square centimeters to 6.25 square centimeters. Related studies also show that the energy conversion efficiency decreases by 60-95% when the area of ​​the photoelectrocatalytic system is increased. Therefore, if a method cannot be found to slow down or even eliminate the rapid performance degradation during the large-scale scaling up of photoelectrocatalytic systems, the engineering application of photoelectrocatalytic systems will be severely hindered.

[0005] The "size effect" in photoelectrocatalysis systems originates from the variations in charge and electron transport processes across systems with different cross-sectional areas. In small-sized laboratory electrodes, photogenerated carriers only need to migrate laterally for less than 1 cm to pass through the current collector and reach the external circuit. However, when large-area electrodes are operating, the distance electrons travel through the conductive layer (or surface) of the anode electrode is significantly extended before being collected by the external circuit wires. Similarly, the release of electrons from the external circuit wires to the reaction zone on the cathode surface also suffers from this extended conduction distance. When electrons pass through the thin and long conductive layer of the electrode, the accumulated resistance causes a significant voltage drop. Two-dimensional multiphysics simulations show that in a neutral electrolyte, when the operating current density is 10 mA / cm², the total voltage drop of a 0.3 cm wide electrode is 50 mV, while that of an 8 cm wide electrode can reach 600 mV (of which the ohmic loss of the conductive substrate accounts for over 60%), resulting in a photoelectric energy utilization efficiency loss as high as 60%-90%. Therefore, suppressing the efficiency decay of large-area electrodes has become a key bottleneck in maintaining the performance of photoelectrocatalysis systems during scale-up. Against the backdrop of continuous innovation in highly efficient catalytic materials such as metal halide perovskites, narrowing the efficiency gap between smaller and larger photoelectrocatalytic electrodes, and developing novel scalable architectures and low-cost large-area manufacturing processes are essential for advancing the commercialization of this technology. However, current research on the design and fabrication of scalable photoelectrodes remains very limited.

[0006] Existing photovoltaic hydrogen production systems frequently adopt scaling-up strategies from mature photovoltaic cells, namely, reducing electron collection resistance by embedding a highly conductive metal network within a conductive substrate. As the density of the highly conductive metal network (such as precious metals like gold and silver) increases, the cumulative surface resistance of the conductive substrate is alleviated, thereby reducing energy conversion efficiency losses due to the "size effect." However, this scaling-up approach fails to fundamentally solve the problem. Electrons on the electrode surface still need to flow through the electrode surface and be collected by the current collector. This means that as the system scales up further, the cost of precious metals required for deploying the highly conductive metal network will increase exponentially, which is unacceptable in practical applications.

[0007] Meanwhile, the structure and function of photovoltaic cells dictate that scaling-up strategies for them only need to optimize electron transport paths without considering ion pathways. However, in photoelectrocatalytic systems, ion transport at the reaction interface must be considered in addition to electron pathways. As the electrode area increases, the concentration gradient formed by the accumulation (or consumption) of product and reactant ions at the interface due to the increased transport distance of reactant ions (such as protons) can lead to significant overpotentials, severely limiting the energy conversion efficiency of the photoelectrocatalytic system. This means that the optimization of ion pathways must be strictly considered when designing scalable photoelectrocatalytic hydrogen production systems. Existing research on photoelectrocatalytic hydrogen production systems has taken this into account; they reduce the ion transmembrane transport distance by minimizing the distance between the dual electrodes and the ion exchange membrane, thereby mitigating the overpotential caused by the ion transmembrane concentration gradient. However, it is certain that with the increase in electrode area, the compression of the distance between the electrode and the ion exchange membrane will lead to a rapid increase in electrolyte flow resistance and a surge in mass transfer resistance. This will quickly offset the advantage of the compression of the distance between the electrode and the ion exchange membrane, thus failing to overcome the "scale-up effect" of the photoelectrocatalytic system. Summary of the Invention

[0008] To address the problem of rapid energy conversion efficiency decline in existing photoelectrocatalytic systems as electrode size increases, this invention proposes a bifunctional photoelectrocatalytic device with ion-electron coupling normal transport and its preparation method. This bifunctional photoelectrocatalytic device reduces the overpotential of photoelectron and electrolyte ion transport by coupling electron and ion transport paths during photoelectrocatalysis.

[0009] The bifunctional photoelectrocatalytic device of the present invention, which uses ion-electron coupling for normal transport, is composed of a conductive substrate and an ion exchange material. The conductive substrate has multiple through holes, and the ion exchange material is disposed in the through holes.

[0010] The preparation method of the bifunctional photoelectrocatalytic device with ion-electron coupling normal transport of the present invention is carried out according to the following steps:

[0011] 1. Fabricating through-holes on a conductive substrate;

[0012] 2. The conductive substrate is polished and cleaned, and then subjected to electrolytic activation treatment;

[0013] 3. Disperse the ion exchange material in a dispersant to obtain an ion exchange material dispersion;

[0014] 4. Place the conductive substrate on the conductive platform, fill the through-holes of the conductive substrate with an ion exchange material dispersion, then connect the conductive substrate to the positive terminal of a power supply, and connect the conductive platform to the negative terminal of a DC power supply. Apply a 1-5V DC current for 1-10 minutes to reorganize the proton conduction channels. Finally, dry the substrate to obtain a bifunctional photocatalytic device with ion-electron coupling normal transport. The reorganized proton conduction channels are formed by the electrophoretic migration of hydrophilic charged groups in the ion exchange material dispersion under the action of a DC electric field, achieving rearrangement along the direction of the electric field and forming an ordered proton conduction channel.

[0015] The principle and beneficial effects of this invention are as follows:

[0016] To address the rapid performance degradation of photoelectrocatalytic systems during amplification, this invention constructs a bifunctional photoelectrocatalytic device to alter electron and ion flow patterns and optimize ion transport pathways. In natural photosynthetic systems, the photosystem drives photogenerated holes and electrons to undergo oxidation and reduction reactions on both sides of a thylakoid membrane. Despite the large specific surface area of ​​the thylakoid membrane, the natural photosynthetic system does not experience performance degradation because the photosystem electron transport chain on the thylakoid membrane facilitates electron flow, and selective ion channels such as proton pumps separate the light and dark reaction regions while maintaining charge balance. This invention innovatively proposes a biomimetic approach to fabricate a bifunctional photoelectrocatalytic device with both electron and ion selective transport capabilities. During photoelectrocatalysis, by loading catalysts onto both sides of a conductive substrate in the bifunctional photoelectrocatalytic device, short-distance electron conduction perpendicular to the normal direction of the conductive substrate is achieved. Simultaneously, selective and directional short-distance ion transport is realized while separating the redox catalytic centers. Electrons no longer migrate through the electrode surface to the external circuit but instead travel through the normal pathway of the substrate, thus overcoming amplification losses caused by uneven resistance distribution on the electrode surface. Meanwhile, by perforating the conductive substrate and injecting an ion exchange material dispersion into the pores, the ion exchange material dispersion will form an ion exchange membrane in the pores after drying, serving as an ion-selective transport channel. This enables rapid transfer and uniform concentration distribution of ions on the electrode surface, thereby overcoming the significant overpotential and uneven secondary current distribution caused by the accumulation of ion concentration gradients.

[0017] In summary, this invention employs an electron-ion coupled normal transport electrode architecture, which simultaneously addresses the issues of surface resistance loss and ion concentration gradient accumulation, overcoming a major bottleneck in existing photoelectrocatalytic system scale-up strategies. It also simultaneously resolves problems such as surface current collection resistance loss and ion concentration polarization overpotential, providing a new approach for the lossless scale-up of photoelectrocatalytic hydrogen production technology. The ion exchange channel structure prepared by the drop casting method in this invention is complete, and its ion resistivity is significantly lower than that of commercial Nafion-117 films, avoiding the negative impact of ion transport resistance on catalytic performance. The bifunctional photoelectrocatalytic device prepared by this invention can achieve near-lossless scale-up of the photoelectrode, reducing energy loss by approximately 90% compared to traditional distributed photoelectrocatalytic hydrogen production systems.

[0018] The present invention provides a bifunctional photoelectrocatalytic device for the transport of electrons and ions in a photoelectrocatalytic system; the photoelectrocatalytic system includes photoelectrocatalytic hydrogen production, photoelectrocatalytic carbon dioxide reduction, photoelectrocatalytic organic synthesis, photoelectrocatalytic pollutant degradation, and photoelectrocatalytic heavy metal recovery. Attached Figure Description

[0019] Figure 1 Optical microscope images of ion exchange materials before and after staining with methylene blue dye;

[0020] Figure 2 SEM image of the ion exchange material inside the through-hole on the conductive substrate of Example 1;

[0021] Figure 3 This is a comparison graph of the ion resistance of Example 1 and the commercial Nafion-117 membrane;

[0022] Figure 4 A comparison diagram of the normal electronic resistance and resistivity of the photoelectrocatalytic devices prepared in Example 1 and Comparative Example 1;

[0023] Figure 5 This is a comparison chart of the solar-to-hydrogen energy conversion efficiency of the systems in Comparative Example 1 and Example 1;

[0024] Figure 6 A schematic diagram of the structure of the integrated system constructed in Example 1;

[0025] Figure 7 A schematic diagram of the integrated system constructed for Comparative Example 1;

[0026] Figure 8 This is a schematic diagram of the conductive substrate in Example 1;

[0027] Figure 9 This is a schematic diagram of the structure of the bifunctional photoelectrocatalytic device with ion-electron coupling normal transport in Example 1. In the figure, 1 is the conductive substrate and 2 is the ion exchange material. Detailed Implementation

[0028] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any reasonable combination of the specific embodiments.

[0029] Specific Implementation Method 1: The bifunctional photoelectrocatalytic device with ion-electron coupling normal transport in this implementation method is composed of a conductive substrate and an ion exchange material. The conductive substrate has multiple through holes, and the ion exchange material is disposed in the through holes.

[0030] This embodiment has the following beneficial effects:

[0031] This embodiment addresses the rapid performance degradation of photoelectrocatalytic systems during amplification by constructing a bifunctional photoelectrocatalytic device to alter electron and ion flow patterns and optimize ion transport pathways. In natural photosynthetic systems, the photosystem drives photogenerated holes and electrons to undergo oxidation and reduction reactions on both sides of the thylakoid membrane. Despite the large specific surface area of ​​the thylakoid membrane, the natural photosynthetic system does not experience performance degradation because the photosystem electron transport chain on the thylakoid membrane facilitates electron flow, and selective ion channels such as proton pumps separate the light and dark reaction regions while maintaining charge balance. This embodiment innovatively proposes a biomimetic approach: fabricating a bifunctional photoelectrocatalytic device with both electron and ion selective transport capabilities. During photoelectrocatalysis, by loading catalysts onto both sides of the conductive substrate in the bifunctional photoelectrocatalytic device, short-distance electron conduction perpendicular to the normal direction of the conductive substrate is achieved. Simultaneously, selective and directional short-distance ion transport is realized while separating the redox catalytic centers. Electrons no longer migrate through the electrode surface to the external circuit but instead travel through the normal pathway of the substrate, thus overcoming amplification losses caused by uneven resistance distribution on the electrode surface. Meanwhile, by perforating the conductive substrate and injecting an ion exchange material dispersion into the pores, the ion exchange material dispersion will form an ion exchange membrane in the pores after drying, serving as an ion-selective transport channel. This enables rapid transfer and uniform concentration distribution of ions on the electrode surface, thereby overcoming the significant overpotential and uneven secondary current distribution caused by the accumulation of ion concentration gradients.

[0032] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the thickness of the conductive substrate is 50μm-3000μm.

[0033] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 1 in that the diameter of the through holes on the conductive substrate is 10-1000μm, and the spacing between adjacent through holes is 0.1-10mm.

[0034] Specific Implementation Method Four: This implementation method differs from Specific Implementation Method One in that the conductive substrate material is conductive graphite, conductive polymer, pure metal, or alloy material.

[0035] Specific Implementation Method Five: This implementation method differs from Specific Implementation Method Four in that the alloy material is an iron-based alloy, gold alloy, silver alloy, copper alloy, aluminum alloy, titanium alloy, or nickel alloy.

[0036] Specific Implementation Method Six: This implementation method differs from Specific Implementation Method One in that the ion exchange material is one or more of the following: perfluorosulfonic acid resin, sulfonated polyether ether ketone, quaternized polysulfone, quaternized polyphenylene ether, sulfonated polysulfone, and polybenzimidazole.

[0037] Specific Implementation Method Seven: The preparation method of the bifunctional photoelectrocatalytic device with ion-electron coupling normal transport in this implementation method is carried out according to the following steps:

[0038] 1. Fabricating through-holes on a conductive substrate;

[0039] 2. The conductive substrate is polished and cleaned, and then subjected to electrolytic activation treatment;

[0040] 3. Disperse the ion exchange material in a dispersant to obtain an ion exchange material dispersion;

[0041] 4. Place the conductive substrate on the conductive platform, fill the through-holes of the conductive substrate with an ion exchange material dispersion, then connect the conductive substrate to the positive terminal of a power supply, and connect the conductive platform to the negative terminal of a DC power supply. Apply a 1-5V DC current for 1-10 minutes to reorganize the proton conduction channels. Finally, dry the substrate to obtain a bifunctional photocatalytic device with ion-electron coupling normal transport. The reorganized proton conduction channels are formed by the electrophoretic migration of hydrophilic charged groups in the ion exchange material dispersion under the action of a DC electric field, achieving rearrangement along the direction of the electric field and forming an ordered proton conduction channel.

[0042] This embodiment addresses the rapid performance degradation of photoelectrocatalytic systems during amplification by constructing a bifunctional photoelectrocatalytic device to alter electron and ion flow patterns and optimize ion transport pathways. In natural photosynthetic systems, the photosystem drives photogenerated holes and electrons to undergo oxidation and reduction reactions on both sides of the thylakoid membrane. Despite the large specific surface area of ​​the thylakoid membrane, the natural photosynthetic system does not experience performance degradation because the photosystem electron transport chain on the thylakoid membrane facilitates electron flow, and selective ion channels such as proton pumps separate the light and dark reaction regions while maintaining charge balance. This embodiment innovatively proposes a biomimetic approach: fabricating a bifunctional photoelectrocatalytic device with both electron and ion selective transport capabilities. During photoelectrocatalysis, by loading catalysts onto both sides of the conductive substrate in the bifunctional photoelectrocatalytic device, short-distance electron conduction perpendicular to the normal direction of the conductive substrate is achieved. Simultaneously, selective and directional short-distance ion transport is realized while separating the redox catalytic centers. Electrons no longer migrate through the electrode surface to the external circuit but instead travel through the normal pathway of the substrate, thus overcoming amplification losses caused by uneven resistance distribution on the electrode surface. Meanwhile, by perforating the conductive substrate and injecting an ion exchange material dispersion into the pores, the ion exchange material dispersion will form an ion exchange membrane in the pores after drying, serving as an ion-selective transport channel. This enables rapid transfer and uniform concentration distribution of ions on the electrode surface, thereby overcoming the significant overpotential and uneven secondary current distribution caused by the accumulation of ion concentration gradients.

[0043] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Method Seven in that: the polishing described in step two uses 320-grit and 600-grit diamond sandpaper;

[0044] The cleaning process described in step two is as follows: the conductive substrate is immersed in anhydrous ethanol for 30 minutes, and then ultrasonically treated for 30 minutes to remove oil and rust; then it is transferred to a mixed acid consisting of 0.5%-10% hydrochloric acid and 0.5%-10% sulfuric acid by volume and immersed for 30 minutes; finally, it is transferred to deionized water and ultrasonically treated for 5 minutes.

[0045] The electrolytic activation process described in step two is as follows: A sulfuric acid solution with a volume fraction of 10%-40% is prepared as the electrolyte; a conductive substrate is used as the anode, and a platinum sheet is used as the cathode; an application of 10-60 mA / cm² is performed. -2 Apply direct current for 1-10 minutes.

[0046] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Method Seven in that the dispersion process described in step three is as follows: the ion exchange material is placed in a dispersant, first sonicated for 30 minutes, and then magnetically stirred for 12 hours;

[0047] The concentration of the ion exchange material dispersion in step three is 0.1-100 wt%;

[0048] The dispersant mentioned in step three is one or a mixture of deionized water, alcohols, dimethyl sulfoxide, N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, chloroform, methanol, ethanol, isopropanol, n-propanol, n-butanol, isobutanol, tert-butanol, ethylene glycol, and glycerol.

[0049] Specific Implementation Method 10: This implementation method differs from Specific Implementation Method 7 in that the drying temperature in step 4 is 40-80℃, and vacuum drying is used until the dispersant is completely volatilized.

[0050] Example 1:

[0051] The fabrication method of the bifunctional photoelectrocatalytic device with ion-electron coupling normal transport in this embodiment is carried out according to the following steps:

[0052] I. Through holes are fabricated on a 316 stainless steel conductive substrate using a laser drilling device;

[0053] The conductive substrate has a thickness of 100 μm; the diameter of the via is 200 μm, and the spacing between adjacent vias is 0.5 mm;

[0054] 2. The conductive substrate is polished and cleaned, and then subjected to electrolytic activation treatment;

[0055] The polishing was performed using 320-grit and 600-grit diamond sandpaper;

[0056] The cleaning process is as follows: the conductive substrate is immersed in anhydrous ethanol for 30 minutes, then ultrasonically treated for 30 minutes to remove oil and rust; then it is transferred to a mixed acid consisting of 6% hydrochloric acid and 6% sulfuric acid by volume for 30 minutes, and finally transferred to deionized water for ultrasonic treatment for 5 minutes.

[0057] The electrolytic activation process is as follows: a 30% (v / v) sulfuric acid solution is prepared as the electrolyte; a conductive substrate is used as the anode, a platinum sheet is used as the cathode, and a 40 mA / cm² electrolytic flux is applied. -2 2 minutes of direct current;

[0058] 3. Disperse 0.5 mg of perfluorosulfonic acid resin (Nafion NR50) in 1 mL of N,N-dimethylacetamide, sonicate for 30 minutes, and then stir magnetically for 12 hours to obtain an ion exchange material dispersion.

[0059] 4. Place the conductive substrate on the conductive platform, fill the through holes of the conductive substrate with the dispersion of ion exchange material, then connect the conductive substrate to the positive terminal of the power supply, connect the conductive platform to the negative terminal of the DC power supply, apply 3V DC power for 3 minutes to re-reform the proton conduction channel, and finally dry it to obtain a bifunctional photoelectrocatalytic device with ion-electron coupling normal transport.

[0060] The drying temperature is 60°C, and vacuum drying is used until the dispersant is completely evaporated.

[0061] An integrated system was constructed: In the middle of the reactor, an anode chamber and a cathode chamber were formed by a bifunctional photoelectron photocatalyst device with ion-electron coupling normal transport, as described in Example 1. A CdS photocatalyst was loaded on one side of the anode chamber of the bifunctional photoelectron photocatalyst device as the photoanode, and a Pt hydrogen evolution catalyst was loaded on the other side. A 0.5 mol / L glycerol solution dissolved in 1.0 mol / L KOH was used as the electrolyte in the anode chamber to carry out the photocatalytic oxidation of glycerol. A 0.5 mol / L H2O solution was used as the electrolyte in the cathode chamber. 1.5 P 1.5 O4 solution acts as an electrolyte, and an electrocatalytic water splitting reaction to produce hydrogen occurs.

[0062] Comparative Example 1:

[0063] A distributed system was constructed, with an ion exchange membrane (commercial Nafion-117 membrane) separating the anode and cathode chambers in the middle of the reactor. Two 316 stainless steel conductive substrates with through holes, prepared in step two of Example 1, were used. The two conductive substrates were connected by an external circuit. One substrate was loaded with a CdS photocatalyst and placed on the anode chamber side as the photoanode; the other substrate was loaded with a Pt hydrogen evolution catalyst and placed on the cathode chamber side as the cathode. In the anode chamber, a 0.5 mol / L glycerol solution dissolved in 1.0 mol / L KOH was used as the electrolyte to carry out the photocatalytic oxidation of glycerol. In the cathode chamber, a 0.5 mol / L H2O solution was used as the electrolyte. 1.5 P 1.5 O4 solution acts as an electrolyte, and an electrocatalytic water splitting reaction to produce hydrogen occurs.

[0064] test:

[0065] (1) Characterization by optical microscopy

[0066] The cationic dye methylene blue is used to stain the ion exchange material (perfluorosulfonic acid resin) inside the through-holes on a conductive substrate, facilitating optical observation. The strong electrostatic interaction between methylene blue and the sulfonate groups of the perfluorosulfonic acid resin allows methylene blue to bind tightly to Nafion. Figure 1 Optical micrographs of ion exchange materials before and after staining with methylene blue dye; Figure a shows the pores before staining, and Figure b shows the pores after staining. The optical microscope reveals that the conductive substrate has a uniform pore size distribution, and the inner walls of the micron-sized channels are rough, facilitating the adhesion of the ion exchange material. The channels are fully filled with the ion exchange material, and the ion channels remain intact without any breaks.

[0067] (2) SEM characterization

[0068] The ion exchange material within the through-hole of the bifunctional photoelectrocatalytic device with ion-electron coupling normal transport in Example 1 was characterized using scanning electron microscopy. Figure 2 The image shows an SEM image of the ion exchange material inside the through-hole on the conductive substrate of Example 1. It can be observed that the ion exchange material can completely fill the micron-sized pores of the porous substrate, thereby forming ion exchange channels and avoiding cross-contamination of raw materials and products in the anode and cathode reactions.

[0069] (3) Ion resistance test of bifunctional photoelectrocatalytic device with ion-electron coupling normal transport

[0070] The ion resistance and ion conductivity of bifunctional photoelectrocatalytic devices with different substrate pore sizes and different Nafion precursor solution concentrations were measured using the standard four-electrode method for ion-electron coupling normal transport. The measurements were performed in a 0.5MH standard H-type electrolytic cell within a 100 mL standard H-type electrolytic cell. 1.5 P 1.5 In the O4–1.0M KOH two-chamber system, a linear current scan was performed between the two Pt electrodes using a DC power supply, and the potential difference across the membrane was recorded. Figure 3 This is a comparison of the ion resistance of Example 1 and the commercial Nafion-117 membrane; the optimal performance photoelectrocatalytic device (200 μm through-pore diameter, 0.5 mg / mL) -1 The Nafion precursor solution concentration has the lowest ionic resistance of 39.76 Ω·cm. 2 And the highest ionic conductivity is 0.25 mS / cm. -1 The ion-resistor is a commercially available Nafion-117 film ion-resistor (89.45 Ω·cm). 2 The transmembrane resistance of ions was reduced to 55.6%, which is 55.6% of the original value.

[0071] (4) Electronic resistance test of bifunctional photoelectrocatalytic devices

[0072] Figure 4 The image shows a comparison of the normal electronic resistance and resistivity of the photoelectrocatalytic devices prepared in Example 1 and Comparative Example 1. The photoelectrocatalytic device prepared in step four of Example 1 (200 μm custom pore size, 0.5 mg / mL) was measured using a four-probe analyzer. - 1 Nafion precursor solution concentration (0.1 mm thickness) with a normal electron resistivity as low as 1.54 × 10⁻⁶. -6 It has a resistivity of only 0.153 mΩ·cm.

[0073] (5) Solar-to-hydrogen energy conversion efficiency test of the photocatalytic hydrogen production system during electrode area scaling-up: Comparative Example 1 and Example 1 used 0.5 cm 2 -6.25 cm 2Photoelectrocatalytic devices of different sizes were used, with a 300 W xenon lamp as the light source. The hydrogen production was tested using gas chromatography-mass spectrometry and the results were used to calculate the solar-hydrogen energy conversion efficiency. Figure 5 This is a comparison of the solar-to-hydrogen energy conversion efficiency of the systems in Comparative Example 1 and Example 1. The integrated system of Example 1 can overcome electrode surface resistance and ion mass transfer resistance to the maximum extent through electron-ion coupling. Compared with the distributed system of Comparative Example 1, its commercial potential lies in achieving near-lossless scale-up of the reaction system. The solar-to-hydrogen energy conversion efficiency of the distributed system and the integrated system of Example 1 was compared under different catalytic areas, showing that the efficiency increased with the catalytic area increasing from 0.5 cm². 2 Increased to 6.25 cm 2 In Comparative Example 1, the solar-to-hydrogen energy conversion efficiency of the distributed system decreased from 0.401% to 0.066% (a sharp drop of 83.54%), while in Example 1, the integrated system's efficiency decreased from 0.779% to 0.710% (a drop of only 8.86%). The use of a bifunctional photoelectrocatalytic electrode significantly reduced the energy loss of 89.39% during the scale-up of the photoelectrocatalytic hydrogen production system.

Claims

1. A bifunctional photoelectrocatalytic device with ion-electron coupling normal transport, characterized in that: The bifunctional photoelectrocatalytic device with ion-electron coupling normal transport consists of a conductive substrate and an ion exchange material. The conductive substrate has multiple through holes, and the ion exchange material is disposed in the through holes.

2. The bifunctional photoelectrocatalytic device with ion-electron coupling normal transport according to claim 1, characterized in that: The thickness of the conductive substrate is 50μm-3000μm.

3. The bifunctional photoelectrocatalytic device with ion-electron coupling normal transport according to claim 1, characterized in that: The diameter of the through holes on the conductive substrate is 10-1000μm, and the spacing between adjacent through holes is 0.1-10mm.

4. The bifunctional photoelectrocatalytic device with ion-electron coupling normal transport according to claim 1, characterized in that: The conductive substrate is made of conductive graphite, conductive polymer, pure metal, or alloy material.

5. The bifunctional photoelectrocatalytic device with ion-electron coupling normal transport according to claim 4, characterized in that: The alloy material is an iron-based alloy, gold alloy, silver alloy, copper alloy, aluminum alloy, titanium alloy, or nickel alloy.

6. The bifunctional photoelectrocatalytic device with ion-electron coupling normal transport according to claim 1, characterized in that: The ion exchange material is one or a mixture of perfluorosulfonic acid resin, sulfonated polyether ether ketone, quaternized polysulfone, quaternized polyphenylene ether, sulfonated polysulfone, and polybenzimidazole.

7. The method for fabricating a bifunctional photoelectrocatalytic device with ion-electron coupling normal transport as described in claim 1, characterized in that: This method is performed according to the following steps:

1. Fabricating through-holes on a conductive substrate; 2. The conductive substrate is polished and cleaned, and then subjected to electrolytic activation treatment; 3. Disperse the ion exchange material in a dispersant to obtain an ion exchange material dispersion; 4. Place the conductive substrate on the conductive platform, fill the through-holes of the conductive substrate with the dispersion of ion exchange material, then connect the conductive substrate to the positive terminal of the power supply, connect the conductive platform to the negative terminal of the DC power supply, apply 1-5V DC for 1-10 minutes to reform the proton conduction channel, and finally dry to obtain a bifunctional photoelectrocatalytic device with ion-electron coupling normal transport.

8. The method for fabricating a bifunctional photoelectrocatalytic device with ion-electron coupling normal transport according to claim 7, characterized in that: Step two describes polishing using 320-grit and 600-grit diamond sandpaper; The cleaning process described in step two is as follows: the conductive substrate is immersed in anhydrous ethanol for 30 minutes, and then ultrasonically treated for 30 minutes to remove oil and rust; then it is transferred to a mixed acid consisting of 0.5%-10% hydrochloric acid and 0.5%-10% sulfuric acid by volume and immersed for 30 minutes; finally, it is transferred to deionized water and ultrasonically treated for 5 minutes. Step two describes the electrolytic activation process as follows: A sulfuric acid solution with a volume fraction of 10%-40% is prepared as the electrolyte. A conductive substrate is used as the anode, and a platinum sheet is used as the cathode. An application of 10-60 mA / cm² is applied. -2 Apply direct current for 1-10 minutes.

9. The method for fabricating a bifunctional photoelectrocatalytic device with ion-electron coupling normal transport according to claim 7, characterized in that: The dispersion process described in step three is as follows: the ion exchange material is placed in a dispersant, first sonicated for 30 minutes, and then magnetically stirred for 12 hours; The concentration of the ion exchange material dispersion in step three is 0.1-100 wt%; The dispersant mentioned in step three is one or a mixture of deionized water, alcohols, dimethyl sulfoxide, N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, chloroform, methanol, ethanol, isopropanol, n-propanol, n-butanol, isobutanol, tert-butanol, ethylene glycol, and glycerol.

10. The method for fabricating a bifunctional photoelectrocatalytic device with ion-electron coupling normal transport according to claim 7, characterized in that: The drying temperature in step four is 40-80℃, and vacuum drying is used until the dispersant has completely evaporated.

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