Preparation method and application of a photo-fuel cell (PFC) based on degradation of bisphenol a and reduction of carbon dioxide

Abstract

The application discloses a preparation method and application of a photo-fuel cell (PFC) based on degradation of bisphenol A and reduction of carbon dioxide, wherein the photo-fuel cell comprises a photo-anode and a biological cathode, the photo-anode is a TiO2@CdS / ITO electrode, and the biological cathode is an FDH / DA / PANi / CC electrode.The photo-fuel cell can not only effectively degrade BPA, but also has a degradation rate of 100%; the constructed FDH / DA / PANi / CC biological cathode can efficiently reduce CO2 into formic acid, and the yield is 3.7μmol·h ‑1 -1 . Compared with other photo-fuel cells, the degradation rate of BPA and the yield of formic acid are obviously improved; in addition, the constructed photo-fuel cell can also effectively generate electricity, and the maximum current density and power density are 271μA cm ‑2 -2 and 67.2μW cm ‑2 -2 respectively.

Description

Technical Field

[0001] This invention belongs to the technical field of combining organic pollution degradation and carbon dioxide reduction, and particularly relates to a method for preparing and applying a photofuel cell (PFC) based on bisphenol A degradation and carbon dioxide reduction. Background Technology

[0002] In recent years, rapid global industrial development has led to severe environmental water pollution. Although water quality has improved significantly, the total amount of water pollutants remains high, undoubtedly posing a threat to human health. Bisphenol A (BPA) is a known endocrine disruptor chemical that is widely released into the environment and water through BPA-based waste and BPA-containing wastewater. Due to the high stability and cumulative nature of BPA, an efficient, low-cost, and sustainable method for its removal is needed. In recent years, photocatalysis technology has received increasing attention due to its advantage of directly utilizing solar energy to degrade harmful pollutants in water. Titanium dioxide (TiO2) has proven to be the most representative BPA degradation material due to its good stability, non-toxicity, and low cost. However, its absorption band is primarily in the ultraviolet region, which greatly limits its application. To improve photocatalytic performance, TiO2 needs to be combined with other semiconductor materials to extend its absorption wavelength to the visible light range. CdS is an n-type semiconductor with a strong response to visible light. Furthermore, the electrons on its CB phase are relatively negative, giving it a strong reducing ability.

[0003] Although the photocatalytic degradation of BPA is mild and efficient, the direct emission of the final product, CO2, into the atmosphere exacerbates the greenhouse effect. Therefore, converting carbon dioxide into chemical fuels is increasingly popular worldwide because it not only reduces atmospheric carbon dioxide but also yields valuable chemicals. Natural photosynthesis, driven by solar energy, reduces carbon dioxide into biomass energy, providing nutrients for life in a sustainable manner. Their high efficiency stems from efficient enzyme catalysis and a fine electron transfer chain after light harvesting; therefore, enzymatic CO2 reduction has been extensively studied. In terms of enzyme catalysis, formate dehydrogenase (FDH), which reduces CO2 to formate, is receiving increasing attention. FDH can convert carbon dioxide to formate not only at room temperature, normal pressure, and in neutral aqueous solutions but also with 100% selectivity. Studies have found that methyl viologen (MV)... 2+ NADH and its derivatives can serve as artificial coenzymes for biocatalysts, reducing CO2 in the absence of natural coenzyme NADH and electron mediators. This simplifies electron transfer steps, reduces energy loss, and improves the efficiency of carbon dioxide reduction.

[0004] Therefore, photocatalytic fuel cells (PFCs) assembled through photocatalytic degradation and enzymatic CO2 reduction can not only degrade harmful pollutants but also yield valuable chemical substances. However, the low CO2 concentration in solution limits contact with the catalyst, resulting in low reduction efficiency. To overcome the CO2 mass transport limitation, CO2 reduction catalysts are immobilized on carbon-based porous gas diffusion layers (GDLs) to form gas diffusion electrodes (GDEs). Due to the hydrophobicity of GDLs, CO2 diffusion near the cathode interface is significantly improved. The type of GDL determines the effectiveness of these transfers. Carbon cloth or carbon paper are the most commonly used GDL materials in fuel cell applications. Summary of the Invention

[0005] Purpose of the invention: The purpose of this invention is to provide a photofuel cell (PFC) based on bisphenol A degradation and carbon dioxide reduction.

[0006] Another objective of this invention is to provide a method for preparing a photoelectric fuel cell (PFC) based on bisphenol A degradation and carbon dioxide reduction.

[0007] Technical solution: In order to achieve the above objectives, the present invention provides a photofuel cell (PFC) based on bisphenol A degradation and carbon dioxide reduction. The photofuel cell includes a photoanode and a biological cathode. The photoanode is a TiO2@CdS / ITO electrode, and the biological cathode is an FDH / DA / PANi / CC electrode.

[0008] The method for preparing a photoelectric fuel cell (PFC) based on bisphenol A degradation and carbon dioxide reduction according to the present invention includes the following steps:

[0009] (1) Add cadmium acetate and thiourea to a SiO2 nanosphere suspension, stir evenly at room temperature, heat, wash the precipitate and place it in NaOH to generate CdS hollow nanospheres.

[0010] (2) Tetrabutyl titanate was added to a suspension of CdS hollow nanospheres, stirred and mixed at room temperature, heated, washed and dried to generate TiO2@CdS composite.

[0011] (3) The TiO2@CdS composite was dissolved in Nafion solution and mixed, then dropped onto ITO and dried to form a photoanode TiO2@CdS / ITO;

[0012] (4) Preparation of PANi hydrogel solution: phytic acid, aniline monomer and ammonium persulfate are mixed, and carbon cloth (CC) is soaked in the hydrogel solution and then taken out. The soaked CC is then soaked in water overnight and then naturally dried to generate PANi / CC.

[0013] (5) Dissolve 4,4'-bipyridine and 2-bromoethylamine hydrobromide in acetonitrile, heat to react, filter to obtain precipitate and dry to obtain 1,1'-diethylamino-4,4'-bipyridine salt (DA);

[0014] (6) Drop glutaraldehyde onto PANI / CC, let it dry naturally, then drop DA onto it, and let it dry naturally to form DA / PANi / CC;

[0015] (7) FDH is dropped onto DA / PANi / CC, and after the reaction, FDH / DA / PANi / CC biocathode is generated.

[0016] Furthermore, in step (1), the molar ratio of cadmium acetate to thiourea is 1:1-10.

[0017] Further, in step (2), 100-300 μL of tetrabutyl titanate is added to a CdS hollow nanosphere suspension with a concentration of 1-5 mg / mL.

[0018] Furthermore, in step (4), the volume ratio of phytic acid to aniline is 1-5:1, and the mass fraction of ammonium persulfate is 1%-10%.

[0019] Furthermore, in step (5), the molar ratio of 4,4'-bipyridine to 2-bromoethylamine hydrobromide is 1:5-15.

[0020] Further, in step (6), 50–200 μL of DA with a concentration of 10–30 mg / mL is added dropwise to a depth of 5 cm. 2 On the electrodes.

[0021] The present invention relates to the application of photo-fuel cells (PFCs) based on bisphenol A degradation and carbon dioxide reduction in the degradation of organic pollutants or the reduction of carbon dioxide.

[0022] Preferably, the photovoltaic fuel cell (PFC) is used in the degradation of the organic pollutant BPA.

[0023] Preferably, the photoanode TiO2@CdS / ITO degrades BPA under light irradiation, and the biocathode FDH / DA / PANi / CC reduces CO2 to formic acid.

[0024] Working Principle: This invention achieves the degradation of organic pollutant BPA, the reduction of CO2 to formic acid, and electricity generation through the construction of a photovoltaic fuel cell. Firstly, under simulated natural light irradiation, the designed TiO2@CdS / ITO photoanode can efficiently remove recalcitrant BPA. Due to its heterojunction formation, it can effectively suppress photogenerated electron-hole (e-hole) interactions. - —h + ) compounding, thereby producing more h +It is used for BPA degradation. Simultaneously, the generated photoexcited electrons can be transferred to the cathode via an external circuit. The FDH / DA / PANi / CC biocatalytic cathode, after accepting electrons, can reduce CO2 to formic acid. Finally, the constructed battery can also efficiently generate electricity.

[0025] Photofuel cells, which combine pollutant degradation and CO2 reduction, require not only a more positive valence band (VB) value for pollutant degradation but also a more negative conduction band (CB) value for CO2 reduction. Titanium dioxide (TiO2) has proven to be the most representative BPA degradation material due to its highly positive valence band (VB) potential under illumination, which effectively degrades BPA. However, its CB value is insufficient for CO2 reduction, and its absorption band is primarily in the ultraviolet region, which significantly limits its application. In natural photosynthesis, the photosystems PSII and PSI are highly effective for water oxidation. Because they form a heterojunction, electrons generated by PSII and holes generated by PSI combine, effectively separating the two types of electrons and improving water oxidation efficiency. Therefore, combining TiO2 with other materials to form a heterojunction not only yields a more negative CB value for CO2 reduction but also extends its absorption wavelength to the visible light range, improving light absorption efficiency. CdS is an n-type semiconductor with a strong response to visible light. Furthermore, the electrons on its CB (carbon dioxide) are relatively negative and possess strong reducing power. Therefore, the heterojunction formed by combining TiO2 and CdS in this invention can effectively suppress charge recombination, improve charge separation efficiency, and expand the light absorption range. This not only allows more holes generated by TiO2 to be used to degrade BPA, increasing its degradation rate, but also allows electrons generated by CdS to effectively reduce CO2. Covalently linking FDH and DA together with glutaraldehyde on PANi / CC to form FDH / DA / PANi / CC, used as a biocathode, constructs a fast electron transfer chain, which is beneficial to the efficiency of CO2 reduction to formic acid. It is rare to find a combination of pollutant degradation and CO2 reduction; most methods combine pollutant degradation with O2 reduction, which leads to the release of CO2 into the atmosphere, increasing the greenhouse effect.

[0026] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0027] (1) In this invention, CdS nanospheres with hollow structures are synthesized, and TiO2 nanoparticles are loaded inside and on the surface to form a TiO2@CdS heterojunction composite for use as a photoanode;

[0028] (2) The formation of heterojunctions can effectively suppress photogenerated electron-hole pairs (e-p-hole pairs). - —h + ) compounding, thereby producing more h +Used for BPA degradation, effectively improving its degradation rate;

[0029] (3) Polyaniline hydrogel (PANi) is generated in situ on carbon cloth (CC), and an artificial coenzyme DA is synthesized to replace the natural coenzyme NADH as an electron carrier and covalently linked to PANi to form DA / PANi / CC, which can rapidly transfer electrons.

[0030] (4) FDH and DA / PANi / CC were connected by glutaraldehyde to form FDH / DA / PANi / CC, which was used as a biological cathode, and an electron fast transfer chain was constructed.

[0031] (5) A fuel cell was assembled by assembling TiO2@CdS photoanode and FDH / DA / PANi / CC biocathode. The degradation efficiency of BPA reached 100%, and CO2 was efficiently reduced to formic acid with a formic acid yield of 3.7 μmol·h⁻¹. -1 Compared with other photovoltaic fuel cells, BPA degradation rate and formic acid yield are significantly improved;

[0032] (6) The constructed photovoltaic fuel cell can also effectively generate electricity, with a maximum current density and power density of 271 μA / cm³. -2 and 67.2 μW cm -2 . Attached Figure Description

[0033] Figure 1 a is a field scanning electron microscope (SEM) image of the CdS hollow nanospheres. Figure 1 bd is a transmission electron microscopy (TEM) image of CdS hollow nanospheres and its elemental mapping diagram.

[0034] Figure 2 a and b are transmission electron microscopy (TEM) images and elemental mapping diagrams of TiO2@CdS. Figure 2 c represents the X-ray diffraction patterns of TiO2, CdS, and TiO2@CdS. Figure 2 d is the field scanning electron microscope characterization image of PANI / CC.

[0035] Figure 3 For DA 1 H-NMR spectrum.

[0036] Figure 4 a is the cyclic voltammetry curve of DA. Figure 4 b represents the cyclic voltammetry curves of CC, PANi / CC, and DA / PANi / CC. Figure 4 c is the standard curve of FDH. Figure 4 d represents the UV absorption spectrum of the enzyme loading of FDH / DA / PANi / CC.

[0037] Figure 5 a is the standard curve for HPLC detection of BPA. Figure 5 b is the standard curve for the HPLC detection of formic acid. Figure 5 c represents the time-dependent degradation rate of BPA after the cells were assembled using TiO2, CdS, and TiO2@CdS as photoanodes. Figure 5 d represents the kinetic curves of BPA degradation rate versus time after the cells are assembled using TiO2, CdS, and TiO2@CdS as photoanodes. Figure 5 e is a graph showing the change in formic acid production over time. Figure 5 f is the current response diagram corresponding to the PFC system.

[0038] Figure 6 a represents the polarization curves of the cells assembled with TiO2, CdS, and TiO2@CdS as photoanodes. Figure 6 b is a graph showing the changes in BPA degradation rate and formic acid production with the number of cycles.

[0039] Figure 7 a represents the photocurrent-time plots for TiO2, CdS, and TiO2@CdS. Figure 7 b shows the fluorescence spectra of TiO2, CdS, and TiO2@CdS. Figure 7 c represents the fluorescence lifetime diagrams of TiO2, CdS, and TiO2@CdS. Figure 7 d represents the paramagnetic resonance spectra of TiO2, CdS, and TiO2@CdS under both light and dark conditions.

[0040] Figure 8 a represents the diffuse reflectance UV absorption spectra of TiO2, CdS, and TiO2@CdS solids. Figure 8 b is the band gap diagram of TiO2. Figure 8 c is the bandgap diagram of CdS. Figure 8 d represents the valence band diagram of TiO2 and CdS obtained by XPS testing.

[0041] Figure 9 This is a schematic diagram of the mechanism of a photofuel cell based on BPA degradation and CO2 reduction. Detailed Implementation

[0042] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0043] Formate dehydrogenase (FDA) from *C. boidinic* was purchased from Supertech Biotechnology Co., Ltd. (Shanghai, China, 1.56 U / mg). Ethyl orthosilicate, ammonium hydroxide, anhydrous ethanol (CH3CH2OH), acetone, potassium chloride, sodium hydroxide, and ammonium persulfate were purchased from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China). Cadmium acetate (C4H6CdO4·2H2O), thiourea, tetrabutyl titanate, glutaraldehyde, 4,4'-bipyridine, 2-bromoethylamine hydrobromide, phytic acid, aniline, silica nanospheres (300 nm), pentafluorobenzene bromide (BM-PFB), and proton exchange membrane (Nafion 117) were purchased from Aladdin (Shanghai, China). Nafion solution was purchased from Sigma-Aidrich (USA). Carbon cloth (CC) was purchased from Keshenghe (Suzhou, China). Indium tin oxide conductive glass (ITO) was purchased from a conductive product store (Shenzhen, China). All reagents did not require further purification. Deionized water with a resistivity of 18.2 MΩ was prepared using the Milli-Q purification system.

[0044] Xenon lamp light source (Popular, Beijing, China); field scanning electron microscope (Frequency Electronics, Shanghai, China); transmission electron microscope (Frequency Electronics, Shanghai, China); fluorescence spectrometer (HORIBA, USA); UV-Vis spectrophotometer (Agilent, USA); 1 H-NMR spectrometer (Bruker, Germany); X-ray diffractometer (Rigaku Corporation, Japan); High-performance liquid chromatograph (Shimadzu, Japan); Paramagnetic resonance spectrometer (Bruker, Germany); Chenhua electrochemical workstation (Shanghai, China); Ultrasonic cleaner (Suzhou, China); Heating stirrer (Aika Corporation, Suzhou, China); Electric drying oven (Jinghong Corporation, Shanghai, China).

[0045] The Tris buffer solution in this embodiment of the invention is: 50 mmol / L -1 Tris(hydroxymethyl)aminomethane, pH 7.0.

[0046] Example 1

[0047] Synthesis of CdS hollow nanospheres (CdS HS)

[0048] 300 mg SiO2 was dispersed in 50 mL H2O and then sonicated for 30 minutes to dissolve it uniformly. Then, 5 mL of 0.2 M C4H6CdO4·2H2O and 5 mL of 0.8 M thiourea were added dropwise to the SiO2 nanosphere suspension, and the mixture was stirred at room temperature for 30 minutes. The mixture was then transferred to a 100 mL sealed PTFE-lined stainless steel autoclave and reacted at 140 °C for 12 hours. After cooling to room temperature, the precipitate was washed three times with distilled water and then added to 50 mL of 0.5 M NaOH solution, reacting at 80 °C for 4 hours. Finally, the precipitate was washed three times with distilled water and dried overnight at 80 °C to obtain CdS hollow nanospheres (CdS HS).

[0049] The dried CdS hollow nanospheres were characterized using field scanning electron microscopy and transmission electron microscopy to observe whether the morphology of the synthesized material met the requirements. Figure 1 As shown in figure a, field scanning electron microscopy results indicate that the synthesized CdS hollow nanospheres have a distinct spherical shape; as Figure 1 As shown in Figures b and d, transmission electron microscopy and EDS elemental mapping reveal that the synthesized CdS hollow nanospheres possess a distinct hollow structure. These test results indicate that the synthesized CdS hollow nanospheres exhibit uniform morphology, good dispersibility, and a diameter of approximately 400 nm.

[0050] Example 2

[0051] Synthesis of TiO2@CdS

[0052] First, 72 mg of CdS HS prepared in Example 1 was dispersed in 50 mL of CH3CH2OH and then sonicated for 10 minutes to mix. Then, 170 μL of tetrabutyl titanate was added dropwise to the CdS HS suspension, and the mixture was stirred at room temperature for 12 hours. Afterward, the mixture was transferred to a 100 mL sealed polytetrafluoroethylene-lined stainless steel autoclave and reacted at 170 °C for 12 hours. After cooling to room temperature, the precipitate was washed three times with distilled water and dried overnight at 80 °C to obtain the TiO2@CdS composite.

[0053] The dried TiO2@CdS was characterized by transmission electron microscopy, such as... Figure 2 As shown in a and b, transmission electron microscopy and their EDS elemental mapping diagrams demonstrate the successful loading of TiO2 onto the surface and interior of CdS HS, increasing its diameter to 500 nm; Figure 2 As shown in Figure c, the powder X-ray diffraction (PXRD) pattern shows that diffraction peaks at 37.98° and 62.88° appeared on TiO2@CdS HS after synthesis, which are diffraction peaks belonging to TiO2.

[0054] Example 3

[0055] Preparation of TiO2@CdS / ITO photoanodes

[0056] 10 mg of the TiO2@CdS complex prepared in Example 2 was dispersed in 400 μL of 1% Nafion solution and sonicated to ensure homogeneity. Then, the mixture was uniformly dropped onto ITO (7 cm³). 2 After natural drying, it is further dried in an oven at 80℃ to form TiO2@CdS / ITO photoanode.

[0057] 10 mg of the CdS HS prepared in Example 1 was dispersed in 400 μL of 1% Nafion solution and sonicated to ensure homogeneity. Then, the mixture was uniformly dropped onto ITO (7 cm⁻¹). 2 After natural drying, the material is further dried in an oven at 80°C to form the control group CdS / ITO photoanode.

[0058] 170 μL of tetrabutyl titanate was added dropwise to 50 mL of CH3CH2OH, and stirred at room temperature for 12 hours. The mixture was then transferred to a 100 mL sealed PTFE-lined stainless steel autoclave and reacted at 170 °C for 12 hours. After cooling to room temperature, the precipitate was washed three times with distilled water and dried overnight at 80 °C to obtain TiO2. 10 mg of the prepared TiO2 was dispersed in 400 μL of 1% Nafion solution and sonicated to ensure homogeneity. Then, the mixture was uniformly dropped onto ITO (7 cm⁻¹). 2 After natural drying, it is further dried in an oven at 80℃ to form a TiO2 / ITO photoanode.

[0059] Example 4

[0060] Synthesis of PANi / CC

[0061] First, two solutions for synthesizing PANi hydrogel were prepared: solution A (0.921 mL phytic acid and 0.458 mL aniline monomer dissolved in 2 mL H2O) and solution B (0.286 g ammonium persulfate dissolved in 1 mL H2O). The prepared solutions were stored in a refrigerator at 4°C. Then, solutions A and B were thoroughly mixed to generate a PANi hydrogel solution, and carbon cloth (CC) was immediately immersed in the PANi hydrogel solution. After immersion for 10 seconds, the CC was removed before polymerization and refrigerated overnight at 4°C. To remove excess oligomers and ions, the PANi / CC electrode was removed from the 4°C refrigerator, immersed in deionized water at room temperature for over 10 hours, and then allowed to air dry.

[0062] The dried PANi / CC electrode was characterized using field scanning electron microscopy, such as... Figure 2As shown in d, the field scanning electron microscope characterization image of PANi / CC shows that the PANi / CC hydrogel electrode exhibits a continuous, layered three-dimensional nanofiber network with a diameter of approximately 60 nm.

[0063] Example 5

[0064] Synthesis of DA

[0065] Weigh 0.156 g of 4,4'-bipyridine and 2.049 g of 2-bromoethylamine hydrobromide into a 100 mL flask and dissolve them in 50 mL of acetonitrile. Heat the solution to 90 °C and reflux for 24 hours. Filter the solution to obtain a precipitate, wash it three times with acetonitrile, and then dry the precipitate overnight in an oven at 80 °C to obtain 1,1'-diethylamino-4,4'-bipyridine salt (DA).

[0066] The dried DA was characterized by NMR. Figure 3 What is shown is DA 1 The 1H-NMR spectrum data is as follows: 1 H-NMR (600MHz, DMSO-d6): δ 9.19 (d, J = 6.0 Hz, 4H), 8.60 (d, J = 6.0 Hz, 4H), 5.06 (t, J = 6.0 Hz, 4H), 3.74 (t, J = 6.0 Hz, 4H).

[0067] Example 6

[0068] Synthesis of DA / PANi / CC

[0069] 100 μL of glutaraldehyde (0.1%) was added dropwise to a surface with a geometrical surface area of ​​5 cm². 2 The PANi / CC electrode prepared in Example 4 was dried at room temperature. 100 μL of DA (20 mg / mL) prepared in Example 5 was added dropwise to the dried electrode and allowed to air dry.

[0070] The dried DA / PANi / CC electrode was characterized by cyclic voltammetry (CV). Figure 4 Figure a shows the CV plot of pure DA, indicating a reduction peak at -0.598V. Meanwhile, as... Figure 4 As shown in b, the dried DA / PANi / CC electrode also showed a reduction peak at -0.598V, indicating that DA was successfully fixed on PANi / CC using glutaraldehyde as a crosslinking agent.

[0071] Example 7

[0072] Fabrication of FDH / DA / PANi / CC electrodes

[0073] Six U of formate dehydrogenase (FDH) was dropped onto the DA / PANi / CC electrode prepared in Example 6 and dried at 4°C for 6 h. Then, 20 μL of glutaraldehyde (0.1%) was added to the electrode, and the reaction was carried out at 4°C for 4 h to crosslink the enzyme with DA. The FDH / DA / PANi / CC electrode was carefully washed with Tris buffer (50 mM) and stored at 4°C. The FDH loading was determined by an FDH activity assay, such as... Figure 4 As shown in c and d, the load factor reaches 1.05 U cm. -2 .

[0074] Example 8

[0075] Assembly and performance study of photovoltaic fuel cells

[0076] The photoanode TiO2@CdS / ITO (7cm) was prepared in Example 3. 2 ) and the FDH / DA / PANi / CC (5cm) prepared in Example 7 2 The photoanode and biocathode were placed in the anode and cathode chambers of the battery, respectively, separated by a Nafion 117 proton exchange membrane. A 0.1M KCl solution containing 70 mg / L BPA was used as the electrolyte in the anode chamber, and a 0.05M Tris buffer solution containing 0.1M KCl was used as the electrolyte in the cathode chamber. A 300W xenon lamp equipped with a 420nm cutoff filter was used as the light source to illuminate the anode, and CO2 was passed through the cathode chamber.

[0077] The concentration of BPA was determined by HPLC using an X-bridged column (4.6 x 250 mm, C18, 5 mm) and a UV detector, with a methanol / water (70 / 30, v / v) mixture as the mobile phase and a flow rate of 1 mL / min. -1 The measured ultraviolet wavelength was 230 nm. For example... Figure 5 As shown in Figure a, this method exhibits a good detection range (0.5-25 mg / L) and good linearity for BPA concentration detection, with a detection limit of 0.08 mg / L. Furthermore, the concentration of formic acid was determined by HPLC. First, 0.2 mL of PBS (0.2 M, pH 7.6), 0.2 mL of formic acid standard solution, and 1 mL of BM-PFB solution (20 g / L, acetone) were mixed and stirred for 1 min, then reacted in a 60 °C water bath for 1 h to generate the BM-PFB derivative. The reaction mixture was then extracted with 2 mL of n-hexane, and the supernatant was centrifuged. A methanol / water (65 / 35, v / v) mixture was used as the mobile phase at a flow rate of 1 mL / min. -1 The measured ultraviolet wavelength was 225 nm. For example... Figure 5As shown in b, this method has a good detection range (0.5-25 mmol / L) for the concentration detection of formic acid and a good linear relationship, with a detection limit of 0.02 mmol / L.

[0078] After assembling the battery, the anode was irradiated with a 300W xenon lamp equipped with a 420nm cutoff filter, and 0.5mL of anolyte was collected every half hour for HPLC analysis. Figure 5 As shown in Figure c, when TiO2@CdS is used as the photoanode, the concentration of BPA gradually decreases with increasing illumination time, eventually reaching complete degradation in approximately 2.5 hours. In contrast, when TiO2 and CdS are used as photoanodes, the BPA removal rates are only 53.0% and 71.5%, respectively, after 3.5 hours of irradiation. Furthermore, a first-order kinetic model was used to further analyze the reaction kinetics of the photocatalytic degradation rate of BPA by different photoanodes. Figure 5 As shown in Figure d, the apparent rate constant (k) of the TiO2@CdS photoanode was obtained as 1.514 h⁻¹ through kinetic curve fitting. -1 The values ​​are TiO2 (0.226h) -1 ) and CdS(0.369h -1 The efficiency of electron-hole pair separation on the photoanode surface was 6.7 times and 4.1 times that of BPA, respectively. These results indicate that the formation of a heterojunction between TiO2 and CdS improves the electron-hole pair separation efficiency on the photoanode surface and accelerates the degradation of BPA.

[0079] Since the holes generated on the photoanode are used to degrade BPA, the electrons generated by the light are transferred to the cathode via an external circuit for enzyme-catalyzed CO2 reduction. For example... Figure 5 As shown in Figure e, when TiO2@CdS prepared in Example 3 is used as the photoanode, the formic acid yield gradually increases with the increase of irradiation time, eventually reaching 2.22 ± 0.05 mM within 3 hours, corresponding to a formic acid production rate of 3.7 μmol·h⁻¹. -1 In contrast, when the CdS prepared in Example 3 was used as a photoanode, only 0.88 ± 0.06 mM formic acid was detected within 3 hours.

[0080] Furthermore, the current response of the PFC system (with TiO2@CdS / ITO photoanode and FDH / DA / PANi / CC biocathode) is as follows: Figure 5 As shown in f, the current response of the PFC system with TiO2@CdS as the photoanode is 33.93 μA cm⁻¹. -2 The current response is significantly higher than that of the PFC system using CdS as the photoanode (23.39 μA / cm). -2Meanwhile, according to the Faraday efficiency equation, the Faraday efficiency of CO2 reduction to formic acid when TiO2@CdS is used as the photoanode is 85.6%, which is 1.81 times that when CdS is used as the photoanode (47.1%), indicating that the constructed TiO2@CdS photoanode PFC system exhibits excellent performance.

[0081] Finally, the constructed PFC system can also effectively generate electricity. For example... Figure 6 As shown in figure a, using TiO2@CdS as the photoanode yields the best power generation performance, with a maximum photocurrent density of 271 μA cm⁻¹. -2 They are TiO2 (62 μA cm⁻¹) -2 ) and CdS (171 μA cm -2 The power density of these components is 4.38 times and 1.58 times that of [other components], with corresponding maximum power densities of 67.2, 18.9, and 47.7 μW / cm², respectively. -2 This is consistent with the results regarding the BPA degradation rate.

[0082] Stability is crucial for industrial application potential. To test the operational stability of the photovoltaic fuel cell constructed in this invention, five consecutive experiments involving BPA degradation and CO2 reduction were conducted under the same reaction conditions. Figure 6 As shown in b, after the 5th run, the BPA degradation efficiency decreased slightly from 100% to 98%, confirming the good stability of the TiO2@CdS / ITO photoanode. Furthermore, the formic acid yield gradually decreased with each cycle, but remained above 90% after 5 consecutive cycles. This indicates that the photofuel cell we constructed has high operational stability and potential for industrial applications.

[0083] Example 9

[0084] Analysis of the Cooperative Mechanism of PFC System

[0085] To investigate the mechanisms of photocatalytic degradation of BPA and enzyme-catalyzed CO2 reduction in the PFC system, a series of tests were conducted. First, transient photocurrents were measured using different photoanodes, such as... Figure 7 As shown in figure a, TiO2@CdS exhibits a considerably high photocurrent (102.85 μA cm⁻²), which is significantly higher than that of TiO2 (6.36 μA cm⁻²). -2 ) and CdS (65.75 μA cm -2 The values ​​were 16.18 and 1.56 times higher than those of [other materials / organizations]. Furthermore, static photoluminescence (PL) measurements were performed, such as [other measurements / organizations]. Figure 7 As shown in b, TiO2@CdS exhibits the weakest emission intensity, indicating that the heterojunction can significantly alleviate severe charge recombination. Time-resolved transient PL analysis was also performed, as shown in... Figure 7As shown in Figure c, the lifetime of TiO2@CdS is 1.71 ns, which is 6.11 times that of TiO2 (0.28 ns) and 2.19 times that of CdS (0.78 ns). This means that the heterojunction prolongs the electronic lifetime by promoting charge separation. Finally, using DMPO as a trap, the free radicals generated by the photoanode were measured by the EPR method to explore the degradation mechanism of BPA in the PFC system. Figure 7 As shown in d, no signal was observed in the absence of light, while under illumination, the strongest signals of ·OH, ·Cl and ·ClO could be observed in the TiO2@CdS photoanode.

[0086] The enzyme-catalyzed CO2 reduction process was further investigated, and the band structure of the photoanode was measured using UV-Vis diffuse reflectance spectroscopy and XPS analysis. Figure 8 As shown in Figure a, the light absorption capacity of the TiO2@CdS composite remained unchanged. Figure 8 As shown in b and c, the band gaps of TiO2 and CdS are 3.00 eV and 2.23 eV, respectively. Figure 8 As shown in Figure d, the valence band (VB) values ​​of TiO2 and CdS are 2.60 eV and 1.60 eV, respectively, and therefore their corresponding conduction band (CB) values ​​are -0.40 eV and -0.63 eV. Since the CB value of CdS is more negative than the DA reduction potential, electrons generated at the photoanode can be transferred to the cathode to form ·DA. Then, with the cooperation of FDH and ·DA, CO2 is reduced to formic acid.

[0087] Based on the above results, the mechanism of the PFC system based on BPA degradation and CO2 reduction is as follows: Figure 9 As shown, in the anodic reaction chamber, the TiO2@CdS heterojunction photoanode generates electron-hole pairs under illumination. The holes can further oxidize H2O and Cl- to form ·OH, ·Cl, and ·ClO, respectively, which collectively participate in the degradation of BPA. Furthermore, electrons generated at the anode are transferred to the cathode through an external circuit, which can reduce DA to ·DA. Finally, FDH accepts electrons from ·DA, reducing CO2 to formic acid.

[0088] Comparative Example 1

[0089] Comparison of degradation rate and power generation efficiency of organic pollutants with other photovoltaic (electric) fuel cells (P(E)FC) of the present invention

[0090] Compare the results of the present invention (Serial No. 10) with those of Chen et al. (Visible-light responsive photocatalytic fuel cell based on WO3 / W photoanode and Cu2O / Cu photocathode for simultaneous wastewater treatment and electricity generation, 2012) (Serial No. 1), Li et al. (Improved dye removal and simultaneous electricity production in a photocatalytic fuel cell coupling with persulfate activation, 2018) (Serial No. 2), Zeng et al. (Highly-stable and efficient photocatalytic fuel cell based on an epitaxial TiO2 / WO3 / W nanothorn photoanode and enhanced radical reactions for simultaneous electricity production and wastewater treatment, 2018) (Serial No. 3), Ong et al. (A synergistic heterostructured ZnO / BaTiO3 loaded carbon photoanode in photocatalytic fuel cell for degradation of Reactive Red 120 and electricity generation, 2019) (Serial No. 4), Liu et al. (Visible-light photocatalytic fuel cell with BiVO4 / UiO-66 / TiO2 / Ti photoanode efficient degradation of Rhodamine B and stable generation of electricity, 2021) (Serial No. 5), Hu et al. (In-situ fabrication of AgI-BiOI nanoflake arrays film photoelectrode for efficient wastewater treatment,The results of the comparisons with those of the following researchers are shown in Table 1: (6) (Electricity production and enhanced recovery of copper in photocatalytic fuel cell, 2020); (7) (Peroxymonosulfate enhanced antibiotic removal and synchronous electricity generation in a photocatalytic fuel cell, 2019); (8) (Comparative study of persulfate oxidants promoted photocatalytic fuel cell performance: simultaneous dye removal and electricity generation, 2019); and (9) (Peroxymonosulfate activated by photocatalytic fuel cell with g-C3N4 / BiOI / Ti photoanode to enhance rhodamine B degradation and electricity generation, 2022).

[0091] Table 1

[0092]

[0093]

[0094] As shown in Table 1, the present invention has the best organic pollutant degradation rate and high power generation efficiency.

[0095] Comparative Example 2

[0096] Comparison of CO2 reduction to formic acid yields between other photovoltaic (electric) fuel cells (P(E)FC) and the present invention.

[0097] The method of this invention (serial number 8) is compared with those of KuK et al. (Continuous 3D Titanium Nitride Nanoshell Structure for Solar-Driven Unbiased Biocatalytic CO2 Reduction, 2019) (serial number 1), Chai et al. (Biocatalytic micromixer coated with enzyme-MOF thin film for CO2 conversion to formic acid, 2021) (serial number 2), Adachi et al. (Construction of a bioelectrochemical formate generating system from carbon dioxide and dihydrogen, 2018) (serial number 3), Sokol et al. (Photoreduction of CO2 with a FormateDehydrogenase Driven by Photosystem II Using a Semi-artificial Z-SchemeArchitecture, 2018) (serial number 4), Amao et al. (A visible-light driven electrochemical biofuel cell with the function of CO2 conversion to formic acid:coupled thylakoid from microalgae and biocatalyst immobilized electrodes, 2018) (serial number 5), and Yan et al. (Hierarchically porous metal organic framework). A comparison was made between the immobilized formatedehydrogenase for enzyme electrocatalytic CO2 reduction (2022) (No. 6) and Zhang et al. (Electrochemically driven efficient enzymatic conversion of CO2 to formicacid with artificial cofactors, 2021) (No. 7), and the results are shown in Table 2.

[0098] Table 2

[0099]

[0100]

[0101] As shown in Table 2, the present invention has a better yield of CO2 to formic acid, which is significantly higher than that of the prior art.

Claims

1. A photoelectric fuel cell (PFC) based on bisphenol A degradation and carbon dioxide reduction, characterized in that, The photovoltaic fuel cell includes a photoanode and a biological cathode. The photoanode is a TiO2@CdS / ITO electrode, and the biological cathode is an FDH / DA / PANi / CC electrode. The method for preparing the photovoltaic fuel cell (PFC) based on bisphenol A degradation and carbon dioxide reduction includes the following steps: (1) Add cadmium acetate and thiourea to a suspension of SiO2 nanospheres, stir evenly at room temperature, heat, wash the precipitate and place it in NaOH to generate hollow CdS nanospheres. (2) Tetrabutyl titanate was added to a suspension of CdS hollow nanospheres, stirred and mixed at room temperature, heated, washed and dried to generate TiO2@CdS composite. (3) The TiO2@CdS composite was dispersed in Nafion solution, then dropped onto ITO, and dried to form a photoanode TiO2@CdS / ITO; (4) Preparation of PANi hydrogel solution: phytic acid, aniline monomer and ammonium persulfate are mixed, and carbon cloth (CC) is soaked in the mixed solution and then taken out. The soaked CC is then soaked in water overnight and then naturally dried to generate PANi / CC; (5) Dissolve 4,4'-bipyridine and 2-bromoethylamine hydrobromide in acetonitrile, heat to react, filter to obtain precipitate and dry to obtain 1,1'-diethylamino-4,4'-bipyridine salt (DA); (6) Drop glutaraldehyde onto PANI / CC, let it dry naturally, then drop DA onto it, and let it dry naturally to form DA / PANi / CC; (7) FDH is dropped onto DA / PANi / CC, and after the reaction, FDH / DA / PANi / CC biocathode is generated.

2. A method for preparing a photoelectric fuel cell (PFC) based on bisphenol A degradation and carbon dioxide reduction as described in claim 1, characterized in that, The steps include the following: (1) Add cadmium acetate and thiourea to a suspension of SiO2 nanospheres, stir evenly at room temperature, heat, wash the precipitate and place it in NaOH to generate hollow CdS nanospheres; (2) Tetrabutyl titanate was added to a suspension of CdS hollow nanospheres, stirred and mixed at room temperature, heated, washed and dried to generate TiO2@CdS composite. (3) The TiO2@CdS composite was dispersed in Nafion solution, then dropped onto ITO, and dried to form a photoanode TiO2@CdS / ITO; (4) Preparation of PANi hydrogel solution: phytic acid, aniline monomer and ammonium persulfate are mixed, and carbon cloth (CC) is soaked in the mixed solution and then taken out. The soaked CC is then soaked in water overnight and then naturally dried to generate PANi / CC; (5) Dissolve 4,4'-bipyridine and 2-bromoethylamine hydrobromide in acetonitrile, heat to react, filter to obtain precipitate and dry to obtain 1,1'-diethylamino-4,4'-bipyridine salt (DA); (6) Drop glutaraldehyde onto PANI / CC, let it dry naturally, then drop DA onto it, and let it dry naturally to form DA / PANi / CC; (7) FDH is dropped onto DA / PANi / CC, and after the reaction, FDH / DA / PANi / CC biocathode is generated.

3. The method for preparing a photoelectric fuel cell (PFC) according to claim 2, characterized in that, In step (1), the molar ratio of cadmium acetate to thiourea is 1:1-10.

4. The method for preparing a photoelectric fuel cell (PFC) according to claim 2, characterized in that, In step (2), 100-300 mL of tetrabutyl titanate is added to a CdS hollow nanosphere suspension with a concentration of 1-5 mg / mL.

5. The method for preparing a photoelectric fuel cell (PFC) according to claim 2, characterized in that, In step (4), the volume ratio of phytic acid to aniline is 1-5:1, and the mass fraction of ammonium persulfate is 1%-10%.

6. The method for preparing a photoelectric fuel cell (PFC) according to claim 2, characterized in that, In step (5), the molar ratio of 4,4'-bipyridine to 2-bromoethylamine hydrobromide is 1:5-15.

7. The method for preparing a photoelectric fuel cell (PFC) according to claim 2, characterized in that, In step (6), 50-200 mL of DA with a concentration of 10-30 mg / mL is added dropwise to a depth of 5 cm. 2 On the electrodes.

8. The application of the photo-fuel cell (PFC) based on bisphenol A degradation and carbon dioxide reduction as described in claim 1 in the degradation of organic pollutants or the reduction of carbon dioxide.

9. The application according to claim 8, characterized in that, The application of the photovoltaic fuel cell (PFC) in the degradation of the organic pollutant BPA.

10. The application according to claim 8, characterized in that, The photoanode TiO2@CdS / ITO of the photovoltaic fuel cell (PFC) degrades BPA under light, and the biocathode FDH / DA / PANi / CC reduces CO2 to formic acid.

Images