Biological hydrogen type electrolytic tank

Abstract

The invention discloses a biological hydrogen type electrolytic tank, and relates to the technical field of biological hydrogen production. The biological hydrogen type electrolytic tank is composed of an anode-microchannel electrolytic tank-proton exchange membrane (PEM)-cathode structure; the anode material adopts TiO2-C spraying modified carbon cloth, and the carbon cloth provides adsorption sites for shewanella, can digest organic matters generated by the II-stage device and generate bioelectricity, so that the electrolysis voltage is reduced; the micro-channel electrolytic cell is made of a nickel plate material, so that heat transfer and liquid flow are promoted, and pressure is reduced; a TiO2-C-coated Co-Ni-FeO-coated SiO2 catalyst is adopted as a cathode material, and the limitation of a single metal activity point is broken through. According to the method, BioH2-MEC and a novel catalyst are designed through a light-electricity-biology synergistic electrolytic catalysis system, high-oil-content chlorella obtained after dark reaction and by-products such as acetic acid and ethyl alcohol are electrolyzed with high efficiency and low energy consumption, hydrogen and by-product rhzomorph are further obtained, and the energy conversion rate and economic benefits of the system are improved.

Description

Technical Field

[0001] This invention belongs to the field of biohydrogen production technology, specifically a biohydrogen electrolyzer. Background Technology

[0002] Bio-hydrogen production technology, as a green energy technology, boasts advantages such as renewable raw materials and strong environmental compatibility, showing significant potential in the field of green hydrogen production. However, traditional bio-hydrogen production systems generally suffer from bottlenecks such as high carbon emissions, low energy conversion efficiency, and high energy consumption for hydrogen separation. Under the "dual-carbon" strategy, building a clean energy system driven by renewable energy has become a global consensus. However, wind power, photovoltaic power generation, and other new energy power generation are limited by "extreme heat without wind and no light at night," leading to a surge in grid peak-shaving pressure, urgently requiring the development of new technologies that combine pollution control with clean energy co-production.

[0003] Based on this, biomass-based hydrogen production technology exhibits unique advantages: it converts biomass into hydrogen through photothermal catalytic reactions, achieving efficient hydrogen production and stable output. It boasts advantages such as long lifespan, high safety, low pollution, and stable gas production, leading to increasingly widespread hydrogen energy applications. However, current microalgae-based hydrogen production technology still faces challenges such as high carbon emissions, low electron transfer efficiency, low energy conversion efficiency, and high energy consumption for hydrogen separation. Therefore, this invention proposes a biological hydrogen electrolyzer that addresses these issues through a synergistic effect of light, electricity, and biology, achieving efficient hydrogen production and wastewater treatment.

[0004] The information disclosed above in this background section is only for enhancing the understanding of the background section of this invention, and therefore may include prior art that is not known to those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a biological hydrogen electrolyzer to solve the problems in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a biological hydrogen electrolyzer, wherein the biological hydrogen electrolyzer is composed of an "anode-microchannel electrolyzer-proton exchange membrane (PEM)-cathode" structure; the anode material is TiO2-C spray-modified carbon cloth, which provides adsorption sites for Shewanella bacteria, digests the organic matter produced by the stage II device and generates bioelectricity, thereby reducing the electrolysis voltage; the microchannel electrolyzer is made of nickel plate material, which promotes heat transfer and liquid flow and reduces pressure; the proton exchange membrane (PEM) is a hydrogen filtration membrane with high selectivity for hydrogen; and the cathode material is a TiO2-C@Co-Ni-FeO@SiO2 catalyst, which overcomes the limitations of single-metal active sites.

[0007] The present invention also provides a process for preparing the cathode catalyst TiO2-C@Co-Ni-FeO@SiO2 of the above-mentioned biohydrogen electrolyzer, comprising the following steps:

[0008] Step 1, SiO2 activation:

[0009] Weigh out SiO2 and pretreat it. Place the SiO2 support in a muffle furnace and calcine at 300℃ for 2 hours. After cooling, immerse it in 1 M HNO3 solution and ultrasonically clean it for 30 minutes. Rinse it with deionized water until neutral and dry it at 120℃ for later use.

[0010] Step 2, Preparation of precursor solution:

[0011] Weigh out Co(NO3)2·6H2O, Ni(NO3)2·6H2O, and Fe(NO3)3·9H2O according to the molar ratio of Co:Ni:Fe = 3:3:1, dissolve them in an appropriate amount of deionized water, stir magnetically until completely dissolved, and add 0.22 g of PVP K30.

[0012] Step 3: Impregnation, drying, and calcination:

[0013] The pre-activated SiO2 support (14.00 g) was added to the mixed solution, magnetically stirred at 60 °C, and vacuum dried at 80 °C for 12 h. The dried sample was then placed in a muffle furnace and heated to 500 °C to obtain Fe-Co-Ni-O / SiO2.

[0014] Step 4: Upgrading the cathode catalyst:

[0015] TiO2 was acid-washed for 2 hours; carbon fiber, ethanol, PVP K30 and polyethylene glycol were magnetically stirred for 2 hours to obtain a homogeneous carbon slurry. After impregnation-magnetic stirring and ultrasonic dispersion of Ni-Co-Fe@SiO2 catalyst loading, TiO2-C@Co-Ni-FeO@SiO2 with enhanced interfacial bonding was constructed by centrifugation, vacuum drying and nitrogen atmosphere calcination.

[0016] Preferably, in step 2, the mass concentration of PVP K30 is 0.7 wt%.

[0017] Preferably, in step 3, the calcined sample is ground and then passed through an 80-mesh sieve.

[0018] Preferably, in step 4, the carbon fiber mass concentration is 70 wt.%, the ethanol mass concentration is 25 wt.%, the PVPK30 mass concentration is 5 wt.%, and the polyethylene glycol mass concentration is 0.5 wt.%.

[0019] Preferably, in step 4, the centrifugation conditions are 3000 rpm for 10 min; the vacuum drying conditions are 80℃ for 12 h; and the nitrogen atmosphere calcination conditions are 3℃ / min to 400℃ for 2 h.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. This invention utilizes a photo-electro-biological synergistic electrolysis catalytic system, designing BioH2-MEC and a novel catalyst to efficiently and with low energy consumption electrolyze high-oil-content Chlorella and byproducts such as acetic acid and ethanol after the dark reaction, further obtaining hydrogen and the byproduct mycin, thereby improving the system's energy conversion rate and economic benefits.

[0022] 2. This invention uses a TiO2-C@Co-Ni-FeO@SiO2 cathode catalyst, which overcomes the limitations of single-metal active sites, improves catalytic activity and stability, significantly increases hydrogen production rate, and allows the catalyst to be recycled many times and has a long lifespan.

[0023] 3. This invention utilizes a microchannel electrolyzer design and employs nickel plate material to promote heat transfer and liquid flow, thereby reducing pressure and energy consumption. Simultaneously, the anode material is TiO2-C-coated modified carbon cloth, which provides adsorption sites for Shewanella bacteria, generating bioelectricity and further reducing the electrolysis voltage, thus achieving low-energy hydrogen production and efficient wastewater treatment. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0025] Figure 1 A schematic diagram of a Level III low-energy MEC electrolysis enhanced hydrogen extraction unit; (a) a model diagram of a biological hydrogen electrolyzer; (b) a schematic diagram of a biological hydrogen electrolyzer; (c) a structural diagram of the cathode catalyst; and (d) a physical image.

[0026] Figure 2 This is a schematic diagram of a Class I Chlorella photosynthetic carbon fixation and wastewater pretreatment unit; (a) is a schematic diagram of the interior of the alternating vortex flow field CO2 absorber; (b) is a simplified external diagram; and (c) is a physical image.

[0027] Figure 3 The reaction mechanism of hydrogen production unit in the combined light and dark bioreaction of level II; including (a) the molecular mechanism of the reaction and electron transfer; and (b) the molecular mechanism of the dark reaction in the co-culture of bacteria and algae.

[0028] Figure 4The flowchart is for performance evaluation; where (a) MEC; (b) composite hydrogen filtration membrane;

[0029] Figure 5 Experimental data for the hydrogen production unit of the combined light and dark bioreactor in Level II; including (a) performance data table; (b) influence of bacteria-algae ratio and light-dark cycle;

[0030] Figure 6 Experimental data for composite hydrogen filtration membranes; including (a) hydrogen selectivity, (b) hydrogen permeability, (c) thermodynamic resistance, and (d) influencing factors.

[0031] Figure 7 Experimental diagrams showing the effects of different conditions on MEC performance; (a) different voltages; (b) different catalysts; (c) different solution disturbances; the top shows the effect on COD content, and the bottom shows the effect on hydrogen, carbon dioxide, and total gas production. Detailed Implementation

[0032] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0033] Example 1: Structure of a biological hydrogen electrolyzer

[0034] Please see Figure 1 A biological hydrogen electrolyzer consists of an "anode-microchannel electrolyzer-proton exchange membrane (PEM)-cathode" structure.

[0035] The anode material is TiO2-C spray-modified carbon cloth, which provides adsorption sites for Shewanella bacteria, enabling them to digest the organic matter produced by the stage II device and generate bioelectricity, thereby reducing the electrolysis voltage.

[0036] The microchannel electrolyzer uses nickel plate material to promote heat transfer and liquid flow, and reduce pressure; nickel plate has good hydrogen evolution performance and electrical conductivity; compared with the traditional carbon brush that provides solution disturbance, MEC has significant advantages in terms of energy consumption and heat conduction.

[0037] The proton exchange membrane (PEM) uses a hydrogen filtration membrane that is highly selective for hydrogen.

[0038] The cathode material uses a TiO2-C@Co-Ni-FeO@SiO2 catalyst, which overcomes the limitations of single-metal active sites.

[0039] Energy efficiency is enhanced through a photo-electric-biological synergistic mechanism, forming a highly efficient and stable organic matter electrolysis system.

[0040] Example 2: Preparation of cathode catalyst

[0041] The preparation process of the cathode catalyst TiO2-C@Co-Ni-FeO@SiO2 includes the following steps:

[0042] Step 1, SiO2 activation:

[0043] Weigh a certain amount of SiO2 and pretreat it. Place the SiO2 support in a muffle furnace and calcine it at 300℃ for 2 hours. After cooling, immerse it in 1 M HNO3 solution and ultrasonically clean it for 30 minutes. Rinse it with deionized water until neutral and dry it at 120℃ for later use.

[0044] Step 2, Preparation of precursor solution:

[0045] Weigh out Co(NO3)2·6H2O, Ni(NO3)2·6H2O, and Fe(NO3)3·9H2O in a molar ratio of Co:Ni:Fe = 3:3:1, dissolve them in an appropriate amount of deionized water, stir magnetically until completely dissolved, and add 0.22 g of PVP K30 (0.7 wt%).

[0046] Step 3: Impregnation, drying, and calcination:

[0047] The pre-activated SiO2 support (14.00 g) was added to the mixed solution, magnetically stirred at 60℃, and vacuum dried at 80℃ for 12 h. The dried sample was placed in a muffle furnace and heated to 500℃ to obtain Fe-Co-Ni-O / SiO2. The calcined sample was ground and passed through an 80-mesh sieve.

[0048] Step 4: Upgrading the cathode catalyst:

[0049] TiO2 was acid-washed for 2 h; a homogeneous carbon slurry was prepared by magnetic stirring of carbon fiber (70 wt.%), ethanol (25 wt.%), PVP K30 (5 wt.%) and polyethylene glycol (0.5 wt.%) for 2 h. After impregnation-magnetic stirring and ultrasonic dispersion of Ni-Co-Fe@SiO2 catalyst loading, TiO2-C@Co-Ni-FeO@SiO2 was constructed by centrifugation (3000 rpm, 10 min), vacuum drying (80℃, 12 h) and calcination in nitrogen atmosphere (3℃ / min to 400℃, 2 h) to construct a TiO2-C@Co-Ni-FeO@SiO2 with enhanced interfacial bonding.

[0050] Application example: Integrated system application

[0051] The present invention relates to a biological hydrogen electrolyzer applied to a hydrogen production system based on a Chlorella photo-dark combined reaction coupled microbial electrolyzer (MEC). The system consists of an integrated series coupled reaction system comprising a first-stage Chlorella photosynthetic carbon fixation and wastewater pretreatment unit, a second-stage photo-dark combined biological reaction hydrogen production unit, and a third-stage low-energy MEC electrolysis enhanced hydrogen extraction unit (i.e., the biological hydrogen electrolyzer of the present invention).

[0052] Level I Chlorella photosynthetic carbon fixation and wastewater pretreatment unit: Please refer to Figure 2 This unit consists of a CO2 absorber with alternating vortex flow fields and a return gas path. Multiple horizontally inclined transparent baffles and an inner concentric tube create a trapezoidal local spatial region within the reactor. The upper and lower baffles and the shell wall form periodic flow channels, generating alternating vortices in the algal solution in the direction of light attenuation (radial), increasing the mixing intensity and alternating circulation frequency. Computational fluid dynamics (CFD) simulations show that this structure can create multi-stage vortices within the reactor, achieving a turbulent kinetic energy dissipation rate (TED) of 0.5-1.2 W / m. 3 CO2 absorption efficiency increased to 80%.

[0053] Level II Photo-Dark Co-process Biological Hydrogen Production Unit: The principle of the photo-dark co-process hydrogen production and carbon fixation system is as follows: Figure 3 As shown in the diagram, this system, based on a biomass electrolysis system, incorporates a CO2 absorption tank and a combined light-dark bioreactor. When Chlorella is exposed to light, a photosynthesis inhibitor (Photosynthesis II) is added to induce hydrogen production through photosynthesis. When Chlorella is deprived of light, a co-culture system of Clostridium difficile and Chlorella is constructed to treat wastewater and produce hydrogen simultaneously through a dark reaction. The synergistic effect of the combined light-dark system results in a COD removal rate 1.6 times that of a single-phase biochemical reaction and a nitrogen and phosphorus removal rate 2.3 times. Its stable operating time is approximately 300 hours, which is 2-3 times that of a single-phase biochemical reaction; and its hydrogen production efficiency is 2.1 times that of a single-phase biochemical reaction.

[0054] Stage III Low-Energy MEC Electrolysis Enhanced Hydrogen Production Unit: BioH2-MEC and Novel Cathode Catalyst. The BioH2-MEC adopts an "anode-microchannel electrolyzer-proton exchange membrane (PEM)-cathode" structure. The anode material is TiO2-C-coated modified carbon cloth, which provides adsorption sites for Shewanella bacteria, digesting the organic matter produced by the Stage II unit and generating bioelectricity, thereby reducing the electrolysis voltage. The microchannel electrolyzer uses nickel plates to promote heat transfer and liquid flow, reducing pressure. The cathode material uses a TiO2-C@Co-Ni-FeO@SiO2 catalyst, overcoming the limitations of single-metal active sites. Through efficient and low-energy electrolysis of high-oil-content Chlorella and byproducts such as acetic acid and ethanol after the dark reaction, hydrogen and the byproduct mycotoxins are further obtained, improving the system's energy conversion rate and economic benefits. Its hydrogen production rate is 1.9 times that of traditional MEC systems, its energy consumption is 0.55 times that of traditional systems, its COD removal rate is 1.33 times that of traditional systems, its by-product utilization rate is ≥95%, and its catalyst activity remains at 75% or higher for ≥6 cycles. The BioH2-MEC structure is as follows: Figure 1 As shown.

[0055] The mixed gas separation and hydrogen filtration purification unit uses components to clamp a hydrogen filtration composite membrane based on a PAI-SiO2 / UIO-66-NH2 mixed matrix membrane and a carboxyl carbon nanofiber reinforced Nb alloy. This membrane is connected to the syngas discharge path of the stage II and III reactors to achieve mixed gas separation and hydrogen filtration purification. The filtered CO2 and a small amount of impurity gases are then passed into the stage I Chlorella photosynthetic carbon fixation and wastewater pretreatment unit for re-fixation. At 473 K, the composite membrane exhibits a hydrogen permeability of 1600 barrer, an H2 / CO2 selectivity of 90%, an H2 / N2 selectivity of 150%, and an H2 / CH4 selectivity of 100.

[0056] The following experiments test the hydrogen production and carbon fixation performance of the above-mentioned coupling system.

[0057] 1. Performance test of combined light and dark biochemical catalytic conversion:

[0058] 2L of Chlorella culture medium from the first-stage device was input into the second-stage system. The light-dark cycle gradient and the mixing ratio of bacteria and algae were adjusted. After the growth cycle was completed, gas product chromatographic analysis, quantitative detection of algal lipids, and determination of organic matter and nitrogen and phosphorus residues in the treated water were carried out simultaneously. The amount of hydrogen produced by biochemical catalytic conversion and the water purification efficiency were quantitatively analyzed.

[0059] The effects of the photo-dark cycle under the action of photosynthesis II inhibitor on hydrogen production efficiency and wastewater treatment, as well as the effects of the bacteria-algae ratio on hydrogen production efficiency and bio-lipid accumulation, were analyzed experimentally. The results showed that a 7-hour photoperiod and a 9-hour darkperiod significantly promoted co-production of hydrogen. With a bacteria-algae ratio of 1:2, the system's hydrogen production rate was 3.56 LH2 / L / T, and the triglyceride accumulation was 11.6 g / L / T. After one cycle, the COD removal rate was 88.1%, and the nitrogen and phosphorus removal rates were 83.6%, representing increases of 27.2%, 8.4%, 3.64%, and 7.17%, respectively, compared to the single-phase system. The experimental results are as follows: Figure 5 As shown.

[0060] 2. Performance analysis and testing of composite hydrogen filtration membrane:

[0061] The composite hydrogen filtration membrane was fixed in the middle of the gas path, and N2 was introduced (50 mL / min) to raise the temperature to 473 K.

[0062] 1) Hydrogen selectivity determination: Switching to 20% H2 / N2 and H2 / CO2 (300 mL / min, 473 K, 30 min) respectively, the H2 / N2 and H2 / CO2 selectivity were measured. The instrument recorded the outlet H2 concentration in real time (sampling frequency 2 s). -1 Simultaneously monitor N2 and CO2 concentrations.

[0063] 2) Hydrogen permeability measurement: H2 is introduced and the volume of hydrogen before and after passing through the composite membrane is measured to determine the hydrogen permeability.

[0064] Experimental results show that at a temperature of 473 K and a total gas flow rate of 300 mL / min, the hydrogen permeability is 1600 barrer. The selectivities are: H2 / CO2 = 90; H2 / N2 = 150; H2 / CH4 = 100. Data are as follows: Figure 6 As shown.

[0065] 3. MEC Performance Evaluation:

[0066] The effects of auxiliary voltage, catalyst, and feed flow rate were determined using the controlled variable method. The gas and mixture obtained after electrolysis were passed into a gas spectrometer and a COD detector, respectively, to determine the COD degradation rate and hydrogen production efficiency.

[0067] like Figure 7As shown, the experimental results indicate that BioH2-MEC achieves a near 100% degradation rate of chemical oxygen demand (COD) at a solution flow rate of 20 mL / min, which is 20% higher than that of a continuous two-chamber electrolyzer (80%), and the hydrogen production rate (1.38 L / L / d) is 15% higher than that of the latter (1.2 L / L / d). Under an auxiliary voltage of 0.8 V, the COD degradation rate reaches 87%, which is 12% higher than that of a tubular single-chamber electrolyzer (75%), and the hydrogen production rate is 6.2% higher than that of a continuous two-chamber electrolyzer (1.3 L / L / d). When using TiO2-C@Co-Ni-FeO@SiO2 catalyst, the COD degradation rate is 12% higher than that of the Co-Ni-Fe catalyst (75%), and the hydrogen production rate (1.38 L / L / d) is significantly increased by 21%.

[0068] Microbial electrolyzers (MECs) directly utilize organic matter within the system, achieving hydrogen production energy consumption of only 1.2 kWh / m³ (27% of traditional water electrolysis) and a coulombic efficiency of 95%. With the electrolysis voltage optimized to 0.6 V, wastewater treatment energy consumption is reduced to 0.15 kWh / m³, a 75% decrease compared to traditional methods (0.6 kWh / m³). Compared to conventional MECs (2.0~3.0 kWh / m³), energy efficiency is improved by 40%.

[0069] 4. Economic benefits

[0070] Based on the model, the estimated cost of the entire system is 21,000 yuan, as shown in Table 1. Preliminary experimental verification shows that the total annual profit is 35,916 yuan, as shown in Table 2.

[0071] Table 1. Cost Analysis of Hydrogen Production and Carbon Sequestration System Based on Chlorella Photo-Dark Co-reaction Coupled with BioH2-MEC

[0072] cost Unit price (yuan) Quantity / Area Total price (RMB) MEC electrolytic reactor 10000 1 10000 Light-dark bioreactor 9000 1 9000 <![CDATA[CO2 Recycling System]]> 2000 1 2000 total - - 21000

[0073] Table 2. Profit Analysis of the Chlorella Photo-Dark Co-reaction Coupled with BioH2-MEC Hydrogen Production and Carbon Sequestration System

[0074] profit Unit price (yuan / kg) <![CDATA[Quantity (kg / m 3 )]]> Total (yuan / day) Total (RMB / year) hydrogen 2.8 21 58.8 21462 Bacterial 330 0.12 39.6 14454 total - - 98.4 35916

[0075] The annual material cost is approximately 3,500 yuan, and the electricity consumption is 150 kWh, resulting in a total annual cost of 24,575 yuan. Based on the above calculations, the investment payback period is only 0.68 years. Over a 10-year period, a single 10m³ system can generate a profit of 113,410 yuan, demonstrating good economic value.

[0076] 5. Environmental benefits

[0077] Compared to alkaline electrolyzers and anaerobic fermentation for hydrogen production, this hydrogen production and carbon fixation system not only has zero carbon emissions, but can also absorb CO2 to produce green hydrogen, and consumes less energy, making it more environmentally friendly.

[0078] Table 3. Technology Comparison Table

[0079] index This system alkaline electrolytic cell Anaerobic fermentation for hydrogen production Unit hydrogen water consumption <![CDATA[0.8m 3 / kg]]> <![CDATA[10m 3 / kg]]> <![CDATA[2.5m 3 / kg]]> carbon emission intensity -1.2kg / kg 12kg / kg 5.8kg / kg By-product revenue ratio 40% 0% 8% Grid Dependence 5% 100% 40%

[0080] In summary, this system, which combines light and dark hydrogen production with a BioH2-MEC hydrogen extraction unit to produce hydrogen and fix carbon, has high hydrogen production efficiency, low energy consumption, and good economic performance. The investment payback period is only 0.68 years, and the environmental benefits are significant. It provides an innovative solution for the sustainable production of clean energy and the goal of carbon neutrality.

[0081] A photosynthetic hydrogen production module is combined with dark-reaction bacteria-algae co-culture. Under light conditions, the addition of a photosynthetic II inhibitor blocks the PSII reaction of Chlorella, activates hydrogenase activity, and directionally drives microalgal photosynthetic hydrogen production. In a lightless, anaerobic environment, Chlorella absorbs organic matter from wastewater to synthesize bio-oils; simultaneously, hydrogen-producing bacteria are introduced to degrade macromolecular organic matter, improving the efficiency of algal-bacterial synergistic hydrogen production.

[0082] The BioH2-MEC employs an "anode-microchannel-proton exchange membrane (PEM)-cathode" structure: the anode material is TiO2-C-coated modified carbon cloth, which provides adsorption sites for Shewanella bacteria, enabling them to digest organic matter produced by the stage II device and generate bioelectricity, thereby reducing the electrolysis voltage. The microchannel electrolyzer uses nickel plates to promote heat transfer and liquid flow, reducing pressure; nickel plates also exhibit excellent hydrogen evolution performance and electrical conductivity; compared to traditional MECs that use carbon brushes to provide solution disturbance, it offers significant advantages in energy consumption and heat conduction. The cathode material uses a TiO2-C@Co-Ni-FeO@SiO2 catalyst, overcoming the limitations of single-metal active sites. Energy efficiency is enhanced through a photo-electric-biological synergistic mechanism, forming a highly efficient and stable organic matter electrolysis system.

[0083] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A biological hydrogen electrolyzer, characterized in that: The bio-hydrogen electrolyzer consists of an "anode-microchannel electrolyzer-proton exchange membrane (PEM)-cathode" structure. The anode material is TiO2-C spray-modified carbon cloth, which provides adsorption sites for Shewanella bacteria to digest the organic matter produced by the stage II device and generate bioelectricity, thereby reducing the electrolysis voltage. The microchannel electrolyzer uses nickel plate material to promote heat transfer and liquid flow, reducing pressure. The proton exchange membrane (PEM) is a hydrogen filtration membrane with high selectivity for hydrogen. The cathode material uses a TiO2-C@Co-Ni-FeO@SiO2 catalyst, overcoming the limitations of single-metal active sites.

2. The preparation process of the cathode catalyst TiO2-C@Co-Ni-FeO@SiO2 in the bio-hydrogen electrolyzer as described in claim 1, characterized in that, Includes the following steps: Step 1, SiO2 activation: Weigh out SiO2 and pretreat it. Place the SiO2 support in a muffle furnace and calcine it at 300°C for 2 hours. After cooling, immerse it in 1 M HNO3 solution and ultrasonically clean it for 30 minutes. Rinse it with deionized water until neutral and dry it at 120°C for later use. Step 2, Preparation of precursor solution: Weigh out Co(NO3)2·6H2O, Ni(NO3)2·6H2O, and Fe(NO3)3·9H2O according to the molar ratio of Co:Ni:Fe = 3:3:1, dissolve them in an appropriate amount of deionized water, stir magnetically until completely dissolved, and add 0.22 g of PVP K30. Step 3: Impregnation, drying, and calcination: The pre-activated SiO2 support (14.00 g) was added to the mixed solution, magnetically stirred at 60 °C, and vacuum dried at 80 °C for 12 h. The dried sample was then placed in a muffle furnace and heated to 500 °C to obtain Fe-Co-Ni-O / SiO2. Step 4: Upgrading the cathode catalyst: TiO2 was acid-washed for 2 hours; carbon fiber, ethanol, PVP K30 and polyethylene glycol were magnetically stirred for 2 hours to obtain a homogeneous carbon slurry. After impregnation-magnetic stirring and ultrasonic dispersion of Ni-Co-Fe@SiO2 catalyst loading, TiO2-C@Co-Ni-FeO@SiO2 was constructed by centrifugation, vacuum drying and nitrogen atmosphere calcination to build TiO2-C@Co-Ni-FeO@SiO2 with enhanced interfacial bonding.

3. The preparation process according to claim 2, characterized in that: In step 2, the mass concentration of PVP K30 is 0.7 wt%.

4. The preparation process according to claim 2, characterized in that: In step 3, the calcined sample is ground and then passed through an 80-mesh sieve.

5. The preparation process according to claim 2, characterized in that: In step 4, the carbon fiber mass concentration is 70 wt.%, the ethanol mass concentration is 25 wt.%, the PVP K30 mass concentration is 5 wt.%, and the polyethylene glycol mass concentration is 0.5 wt.%.

6. The preparation process according to claim 2, characterized in that: In step 4, the centrifugation conditions are 3000 rpm for 10 min; the vacuum drying conditions are 80℃ for 12 h; and the nitrogen atmosphere calcination conditions are 3℃ / min to 400℃ for 2 h.

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