Preparation method of bifunctionalized carbon-based aerogel and water-vapor device based on the preparation method

Abstract

This invention discloses a method for preparing a bifunctional carbon-based aerogel and a hydrophobic device based on this method, belonging to the field of aerogel technology. The invention involves mixing chitosan, NCNT dispersion, calcium carbonate, anhydrous acetic acid, and deionized water, and then thoroughly stirring the mixture in a water bath to obtain a composite gel. Acetic acid is then added to the composite gel for reaction, followed by freeze-drying to obtain the bifunctional carbon-based aerogel. By inserting aluminum and copper electrodes into the composite gel during the preparation of the bifunctional carbon-based aerogel, followed by the addition of acetic acid for reaction and freeze-drying, an aerogel hydrophobic device is obtained. The bifunctional carbon-based aerogel hydrophobic device prepared by this invention possesses both excellent electrical output and efficient seawater desalination capabilities. It can stably power small electrical appliances and efficiently achieve seawater desalination, showing broad comprehensive application prospects.

Description

Technical Field

[0001] This invention relates to the field of aerogel technology, and mainly to a method for preparing a bifunctional carbon-based aerogel and a water-voltaic device based on the method. Background Technology

[0002] The water cycle is an indispensable part of Earth's ecosystem, maintaining global ecological balance and possessing enormous potential for energy harvesting and resource conversion. However, the efficient development of hydropower still faces challenges such as technological bottlenecks and high costs. Hydrovoltaic technology, with its sustainability, environmental compatibility, and potential in addressing the climate, energy, and water crises, has attracted widespread attention and made significant progress.

[0003] Traditional one-dimensional material-based hydrovoltaic devices provide a good platform for studying confined ion transport, but suffer from problems such as short pulse periods and low ion selectivity. Two-dimensional materials have attracted much attention due to their high specific surface area and structural tunability, but are limited by intermittent output and poor scalability. Three-dimensional materials, with their tunable porosity, ion transport pathways, and surface charge, are gradually becoming a research focus, with aerogels, due to their high porosity and tunable surface properties, becoming an ideal platform for improving hydrovoltaic performance. Nevertheless, current hydrovoltaic generators still face problems such as low power density and intermittent output, limiting their widespread application. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing bifunctional carbon-based aerogels and a water-based photovoltaic device based on this method. The aerogel and water-based photovoltaic device fabrication processes are simple and can achieve high-power power generation and seawater desalination.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for preparing a bifunctional carbon-based aerogel involves mixing chitosan, NCNT dispersion, calcium carbonate, anhydrous acetic acid, and deionized water, and then stirring thoroughly in a water bath to obtain a composite gel. Acetic acid is added to the composite gel to initiate a reaction, and the reaction is followed by freeze-drying to obtain the bifunctional carbon-based aerogel.

[0007] Furthermore, the mass ratio of chitosan, NCNT dispersion, calcium carbonate, anhydrous acetic acid, and deionized water is 1:36:1:0.5:60, and the NCNT content in the NCNT dispersion is 10wt%.

[0008] Furthermore, the water bath temperature is 37°C.

[0009] Furthermore, the ratio of the composite gel to acetic acid is 9g:1.5mL.

[0010] Furthermore, the reaction temperature for adding acetic acid is 37°C.

[0011] A water-based photovoltaic device, which is prepared based on the above-mentioned preparation method, is composed of bifunctionalized carbon-based aerogel, aluminum electrode, and copper electrode.

[0012] Further, chitosan, NCNT dispersion, calcium carbonate, anhydrous acetic acid, and deionized water were mixed and stirred thoroughly in a water bath to obtain a composite gel. The composite gel was filled into a container and aluminum and copper electrodes were inserted. Acetic acid was then added to the composite gel to carry out the reaction. After the reaction, the mixture was freeze-dried to obtain a water-voltaic device.

[0013] Furthermore, the insertion depth of the aluminum electrode in the composite gel is greater than that of the copper electrode in the composite gel.

[0014] Furthermore, the freeze-drying temperature is -70℃ to -60℃, and the freeze-drying time is 3 hours.

[0015] In summary, the present invention has the following beneficial effects:

[0016] The bifunctional carbon-based aerogel prepared by this invention combines high-efficiency power generation and seawater desalination. A single aerogel device can achieve an output current of over 30mA and an open-circuit voltage of approximately 550mV, at a speed of 1kW / m². 2 Seawater desalination can be completed directly under sunlight, with a desalination rate of 1.76 kg·m³. -2 h -1 It can provide stable power to small electrical appliances and efficiently achieve seawater desalination. It has strong environmental adaptability and broad application prospects. Attached Figure Description

[0017] Figure 1 SEM image of the bifunctionalized carbon-based aerogel obtained in Example 1 ( Figure 1 a is a side SEM image of the aerogel; Figure 1 b is a top-view SEM image of the aerogel.

[0018] Figure 2 The image shows the SEM-EDS image of the bifunctionalized carbon-based aerogel obtained in Example 1.

[0019] Figure 3 The figure shows the results of the physicochemical characterization and analysis of the IA-HVG obtained in Example 1. Figure 3 a is the pore size distribution diagram of IA-HVG and CS aerogel; Figure 3 b is the specific surface area diagram of IA-HVG and CS aerogel; Figure 3 c is the surface electrostatic potential distribution diagram of IA-HVG; Figure 3 d is the surface potential line scan of IA-HVG; Figure 3 e is a graph showing the zeta potential measurement results of CS aerogel and IA-HVG; Figure 3 f represents the FTIR spectra of IA-HVG and the raw materials CS and NCNT; Figure 3 g is the XPS analysis plot of C1s in IA-HVG; Figure 3 h represents the Raman spectra of NCNT and IA-HVG; Figure 3 i represents the XRD patterns of NCNT and IA-HVG.

[0020] Figure 4 This is a graph showing the IV characteristics of the IA-HVG device prepared in Example 1;

[0021] Figure 5 The diagram shows the electrical output performance of the devices fabricated using different electrodes (Cu-Al electrode, Cu-Fe electrode, and Cu-graphite electrode) in Example 2.

[0022] Figure 6 The output performance of the IA-HVG device prepared in Example 1 is shown in Example 2 under different lithium chloride concentrations (10%, 15%, 20% and 25%).

[0023] Figure 7 The output performance of the IA-HVG device prepared in Example 1 is shown in Example 2 under different lithium chloride volumes (0.5 mL, 1.0 mL, 1.5 mL and 2.0 mL).

[0024] Figure 8 The output performance of the IA-HVG device prepared in Example 1 under different electrolyte conditions (CaCl2, NaCl, LiCl, seawater, and ZnCl2) is shown in Example 2.

[0025] Figure 9 The graph shows the electrical output performance of the devices prepared under different contents of NCNT (30g, 35g, 36g, 37g and 38g) in Example 2.

[0026] Figure 10 The diagram shows the electrical output performance of the IA-HVG device under plastic film sealing conditions in Example 2.

[0027] Figure 11 The graph shows the load voltage and load current test results of the IA-HVG device prepared in Example 1 under different external resistance conditions in Example 2.

[0028] Figure 12 This is a graph showing the electrical output performance of the IA-HVG device prepared in Example 1 under the optimal load resistance condition in Example 2;

[0029] Figure 13 The results obtained to investigate the generator mechanism of IA-HVG devices are shown in the figure. Figure 13a is a graph showing the electrical output performance of the CS aerogel device; Figure 13 b shows the output voltage of the IA-HVG device prepared in Example 1 at different evaporation rates; Figure 13 c is a comparison graph of the output current of the device fabricated using Cu-Cu electrodes and the IA-HVG device (Cu-Al electrode) fabricated in Example 1; Figure 13 d is a comparison graph of the output voltage of the device fabricated using Cu-Cu electrodes and the IA-HVG device (Cu-Al electrode) fabricated in Example 1; Figure 13 e is a schematic diagram of the generation mechanism of the IA-HVG device).

[0030] Figure 14 The test results are shown in the figure to explore the integration and application performance of IA-HVG devices. Figure 14 a is a comparison of the output voltage of a single IA-HVG device and different numbers of IA-HVG devices connected in series; Figure 14 b is a comparison of the output current of a single IA-HVG device and different numbers of IA-HVG devices connected in parallel. Figure 14 c is a diagram showing six IA-HVG devices connected in series as a power supply for a lighting electronic device; Figure 14 d shows the leakage current detection diagram for a single IA-HVG device; Figure 14 e is a graph showing the results of a single IA-HVG device powering capacitors of different capacities; Figure 14 f is a graph showing the result of charging a commercial capacitor using two IA-HVG devices connected in series.

[0031] Figure 15 The figure shows the seawater desalination performance of the IA-HVG device prepared in Example 1. Figure 15 a is a schematic diagram of a seawater desalination experimental device; Figure 15 b is a comparison of the surface temperature of the IA-HVG device under different illumination conditions; Figure 15 c is a graph showing the mass change of seawater under different light intensities; Figure 15 d represents the evaporation rate of seawater under different light intensities; Figure 15 e is a comparison graph of surface temperature changes of different test systems under the same illumination conditions; Figure 15 f is a comparison graph of mass changes in different test systems under the same illumination conditions; Figure 15 g represents Na in seawater and desalination water + Mg 2+ Ca 2+ and K + Concentration comparison chart). Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] The implementation steps of this invention are as follows: Chitosan, NCNT (nitrogen-doped carbon nanotubes) aqueous dispersion, calcium carbonate, anhydrous acetic acid, and deionized water are mixed in a certain proportion and stirred thoroughly in a water bath to obtain a composite gel; then acetic acid is added to the composite gel for reaction, followed by freeze-drying to obtain a bifunctional carbon-based aerogel. Furthermore, during the preparation of the bifunctional carbon-based aerogel, aluminum and copper electrodes are inserted into the composite gel (the insertion depth of the aluminum electrode in the composite gel is greater than that of the copper electrode), followed by the addition of acetic acid for reaction and freeze-drying to obtain a device based on the bifunctional carbon-based aerogel.

[0034] Example 1

[0035] 1g of chitosan (purchased from Aladdin Reagent Company, product number C105803), 36g of NCNT aqueous dispersion (purchased from Nakat New Materials Technology Co., Ltd., product name 10% aqueous carbon nanotube slurry, with NCNT content of 10wt%), 1g of calcium carbonate, 0.5mL of anhydrous acetic acid, and 60mL of deionized water were added to a beaker and stirred thoroughly in a 37℃ water bath for 1 hour to obtain a composite gel. The composite gel was then filled into a culture dish and aluminum and copper electrodes were inserted (specifically: first, a layer of composite gel was filled to the bottom of a 3.5cm diameter culture dish, and the aluminum electrode was vertically inserted into this layer of composite gel; then another layer of composite gel was filled and the copper electrode was vertically inserted into this layer of composite gel; finally, another layer of composite gel was filled, and the three layers of composite gel were filled from bottom to top). The filler weights were 4g, 3g, and 2g respectively; the aluminum electrode was sheet-shaped, 0.5mm thick and 1.2cm wide, with an insertion depth of 0.83cm in the composite gel and a longitudinal distance of 0.66cm between the bottom of the aluminum electrode and the bottom of the culture dish; the copper electrode was a copper wire with a diameter of 1.5mm, with an insertion depth of 0.33cm in the composite gel and a horizontal distance of 1.5cm between the aluminum and copper electrodes; then 1.5mL of acetic acid was added to the composite gel, and the reaction was carried out at 37℃ for 10 minutes; finally, the culture dish containing the composite gel was placed in a freeze dryer and frozen for 3 hours (freezing temperature -70℃ to -60℃, pressure 1×10⁻⁶). 5Pa), and then freeze-dry (freeze-drying temperature -70℃ to -60℃, pressure 0.9Pa, freeze-drying time 24h) to obtain bifunctional carbon-based aerogel (named IA-HVG) and bifunctional carbon-based aerogel water-voltaic device (i.e. IA-HVG device).

[0036] Comparative Example 1

[0037] CS aerogel and CS aerogel devices were prepared according to the method of Example 1 but without the addition of NCNT aqueous dispersion, and used as a control group.

[0038] The bifunctionalized carbon-based aerogel was observed using scanning electron microscopy and subjected to EDS testing. The results are as follows: Figure 1 , Figure 2 As shown. By Figure 1 It can be seen that IA-HVG possesses a porous structure that forms unobstructed microchannels, enabling efficient water transport within the device. EDS elemental analysis shows that C, O, N, and Ca are uniformly distributed on the surface of IA-HVG, indicating that acetic acid and calcium carbonate have successfully crosslinked with NCNT and CS.

[0039] The physicochemical properties of IA-HVG from Example 1 were analyzed, and the results are shown in the figure. Figure 3 .

[0040] Figure 3 The pore size distribution shown in Figure a indicates that the pore size of IA-HVG is significantly smaller than that of CS aerogel. This structural difference stems from the formation of a denser pore network in IA-HVG, resulting in significantly stronger capillary action.

[0041] Figure 3 b. Specific surface area measurement results show that IA-HVG has a larger specific surface area than CS aerogel, thereby enhancing the interaction potential between water molecules and functional groups.

[0042] To investigate the ion dissociation and diffusion properties of IA-HVG, Kelvin probe force microscopy (KPFM) was performed on IA-HVG. The results are shown in [Figure number missing]. Figure 3 c. Surface electrostatic potential measurements show that the surface potential of IA-HVG is approximately 0.31V (see...). Figure 3 d), consistent with the results of the Zeta potential test (see Figure 3 e).

[0043] Meanwhile, Fourier transform infrared spectroscopy (FTIR) analysis elucidated the surface chemical properties of IA-HVG, CS, and NCNT at 3430 cm⁻¹. -1 and 1628cm -1 The region shows a distinct characteristic peak corresponding to the amino group (-NH2) (see [reference]). Figure 3 f).

[0044] X-ray photoelectron spectroscopy (XPS) analysis showed that the C1s spectrum of IA-HVG exhibited five distinct characteristic peaks at binding energies of 284.5 eV, 284.9 eV, 285.9 eV, 287 eV, and 290.2 eV, corresponding to CC, CN, OCO, OC=O, and π-π bonds, respectively (see [link to X-ray photoelectron spectroscopy]). Figure 3 g).

[0045] Furthermore, the Raman spectra of NCNT and IA-HVG show (see...) Figure 3 h): NCNT has a value of 1334cm -1 1574cm -1 and 2680cm -1 The three distinct bands at the point correspond to defect bands D, G, and 2D, respectively. After crosslinking, the ID / IG ratio (the ID / IG ratio can be used as an indicator of NCNT defects—the higher the ratio, the more defects in CNTs) decreased from 2.77 to 1.58, indicating that crosslinking significantly reduced the surface defect density of NCNTs.

[0046] Figure 3 i shows the X-ray diffraction (XRD) patterns of NCNTs before and after crosslinking. The sharp peak at 26.2° corresponds to the (002) crystal plane of NCNTs. No significant peak shift was observed in IA-HVG, indicating that the interlayer spacing of CCNTs remained unchanged during the aerogel fabrication process.

[0047] Example 2

[0048] To optimize the performance of bifunctional carbon-based aerogel water-voltaic devices, this embodiment systematically studies various factors affecting the output performance of aerogel water-voltaic devices. Based on the device fabrication method shown in Example 1, single-variable experiments are conducted to determine the influencing factors.

[0049] (1) The effect of different electrodes (Cu-Al electrode, Cu-Fe electrode and Cu-graphite electrode) on the electrical output performance of aerogel water photovoltaic devices.

[0050] Using a 20wt% LiCl solution as the electrolyte, 1.5mL of electrolyte was dropped onto the bottom of the device using a pipette. Under conditions of 25℃ and 70% humidity, voltage and current were measured in real time using a digital source oscilloscope (Keithley 2450 source oscilloscope) and a semiconductor picoammeter (Keysight B2900).

[0051] use Figure 4The circuit schematic shown illustrates the current-voltage (IV) characteristic curve of the IA-HVG device prepared in Example 1. The measured short-circuit current (Isc) is 33.36 mA, and the open-circuit voltage (Voc) is 0.55 V. The IV curve exhibits an approximately linear relationship, indicating that the IA-HVG device possesses quasi-ohmic characteristics. When the external resistance is equal to the internal resistance, the device reaches its maximum power output and maximum power density, corresponding to the largest rectangular area that can be plotted in the IV curve (…). Figure 4 Shaded area P m Its value is approximately 657.80 μW·cm. -2 .

[0052] Depend on Figure 5 It can be seen that when copper is used as the positive electrode and inert graphite as the negative electrode, Isc and Voc are approximately 0.43mA and 0.12V, respectively. However, replacing graphite with aluminum electrodes significantly improves the output performance of the IA-HVG device, enabling its instantaneous Isc to reach 34.85mA.

[0053] (2) The effect of the concentration (10wt%, 15wt%, 20wt% and 25wt%) and volume (0.5mL, 1.0mL, 1.5mL and 2.0mL) of lithium chloride solution on the electrical output power of the device.

[0054] To determine the effect of different lithium chloride solution concentrations, 1.5 mL of lithium chloride solution of different concentrations was taken with a pipette and dropped onto the bottom of the device. Under the conditions of 25℃ and 70% humidity, voltage and current were measured in real time using a digital source oscilloscope (Keithley 2450 source oscilloscope) and a semiconductor picoammeter (Keysight B2900).

[0055] To determine the effect of different lithium chloride solution volumes, different volumes of 20wt% lithium chloride solution were taken with a pipette and dropped onto the bottom of the device. Under conditions of 25℃ and 70% humidity, voltage and current were measured in real time using a digital source oscilloscope (Keithley 2450 source oscilloscope) and a semiconductor picoammeter (Keysight B2900).

[0056] The concentration and volumetric amount of lithium chloride directly determine the water absorption of the IA-HVG device. However, excessive water can hinder the evaporation process, thus affecting the overall performance of the device. When the lithium chloride concentration is increased to 20 wt%, the output current and voltage of the IA-HVG device prepared in Example 1 reach their optimal values ​​(see...). Figure 6 Similarly, Isc and Voc exhibit a non-monotonic trend with increasing lithium chloride content: they rise initially, then begin to decline after reaching a certain threshold (see [link to relevant documentation]). Figure 7 ).

[0057] (3) The effect of different electrolyte solutions (CaCl2, NaCl, LiCl, seawater and ZnCl2) on the electrical output power of IA-HVG devices.

[0058] Using different electrolytes with a concentration of 20wt%, 1.5mL of each electrolyte was taken with a pipette and dropped onto the bottom of the device. The voltage and current were measured in real time at a temperature of 20℃-30℃ and a humidity of 60%~70% using a digital source oscilloscope (Keithley 2450 source oscilloscope) and a semiconductor picoammeter (Keysight B2900).

[0059] Depend on Figure 8 The results show that lithium chloride exhibits excellent hygroscopicity, achieving the highest power generation. Even in a seawater environment, the IA-HVG device prepared in Example 1 can instantaneously generate 19.04 mA of Isc and 0.46 V of Voc, fully demonstrating its great potential in seawater evaporation power generation.

[0060] (4) The effect of the content of NCNT aqueous dispersion (30g, 35g, 36g, 37g and 38g) on ​​the electrical output power of aerogel water photovoltaic device.

[0061] Aerogel water-voltaic devices were prepared using different amounts of NCNT aqueous dispersions according to the method in Example 1. Using 20wt% LiCl solution as the electrolyte, 1.5 mL of electrolyte was dropped onto the bottom of the device using a pipette. Under conditions of 25°C and 70% humidity, voltage and current were measured in real time using a digital source oscilloscope (Keithley 2450 source oscilloscope) and a semiconductor picoammeter (Keysight B2900).

[0062] While increasing the NCNT content helps reduce the internal resistance of the device, it also weakens the water evaporation efficiency. The dynamic balance between water evaporation and the internal resistance of the device ultimately determines the optimal NCNT content, i.e., when the NCNT aqueous dispersion is 36g, the Isc and Voc of the aerogel watervoltaic device reach their peak values ​​(see...). Figure 9 ).

[0063] (5) The effect of plastic film encapsulation on the electrical output power of IA-HVG devices.

[0064] The IA-HVG device prepared according to the method of Example 1 was encapsulated using a plastic film. Using a 20wt% LiCl solution as the electrolyte, 1.5 mL of electrolyte was dropped onto the bottom of the device using a pipette. Under conditions of 25°C and 70% humidity, voltage and current were measured in real time using a digital source oscilloscope (Keithley 2450 source oscilloscope) and a semiconductor picoammeter (Keysight B2900).

[0065] Experimental results show (see) Figure 10 Under the same test conditions (standard atmospheric pressure, 25°C, 70% humidity), compared with unencapsulated IA-HVG devices, the reduced moisture evaporation resulting from the plastic film encapsulation of the devices significantly improves power generation efficiency. During the moisture evaporation process, the output performance of IA-HVG devices drops sharply, indicating that moisture evaporation plays a crucial role in the power generation process of IA-HVGs.

[0066] (6) Evaluate the practical applicability of IA-HVG devices as power supplies, using... Figure 11 The circuit shown tests the load voltage (Vload) and load current (Iload) under different external load resistors.

[0067] Using a 20wt% LiCl solution as the electrolyte, 1.5mL of electrolyte was dropped onto the bottom of the device using a pipette. Under conditions of 25℃ and 70% humidity, voltage and current were measured in real time using a digital source oscilloscope (Keithley 2450 source oscilloscope) and a semiconductor picoammeter (Keysight B2900).

[0068] The results show that both Vload and Iload vary with the load resistance and reach their optimal load state at approximately 20Ω, indicating that the device has low internal resistance (see [reference needed]). Figure 11 To investigate the effective output performance of the device, the optimal load resistance (20Ω) was selected for output measurement. The results show ( Figure 12 After 45,000 seconds of continuous discharge, the load power can still be stably maintained at 0.42mW.

[0069] Example 3: Investigating the Generator Mechanism of IA-HVG Devices

[0070] Using a 20wt% LiCl solution as the electrolyte, 1.5mL of electrolyte was dropped onto the bottom of the device using a pipette. Under conditions of 25℃ and 70% humidity, voltage and current were measured in real time using a digital source oscilloscope (Keithley 2450 source oscilloscope) and a semiconductor picoammeter (Keysight B2900).

[0071] First, the power generation performance of the CS aerogel device prepared in Comparative Example 1 was tested. The results showed that the short-circuit current and open-circuit voltage of the CS aerogel device were approximately 0.25 mA and 0.46 V, respectively, which are lower than the corresponding parameters of the IA-HVG device. This indicates that the power generation performance of the device mainly depends on the NCNT structure (see...). Figure 13 a).

[0072] The effect of water evaporation rate on the power generation performance of the IA-HVG device prepared in Example 1 was determined. Figure 13As shown in b, the device output voltage increases with the water evaporation rate and then gradually stabilizes, indicating that the water evaporation process plays a key role in the power generation process.

[0073] To further investigate the water evaporation effect, an aerogel water-voltaic device was fabricated using the method of Example 1 and a copper / copper (Cu / Cu) electrode to eliminate the electrode effect. The final electrical output is entirely attributed to the fluid potential difference generated during the evaporation process (see Example 1). Figure 13 c and Figure 13 d) The Isc value of the aerogel water-voltaic device fabricated using copper / copper (Cu / Cu) electrodes is approximately 0.74 mA, and the Voc value is approximately 60 mV.

[0074] Based on the above observations, a feasible mechanism for power generation within IA-HVG devices is proposed, such as... Figure 13 As shown in e. When no electrolyte is present, the device voltage will be zero. Once lithium chloride is introduced and evaporation begins, ions will begin to diffuse within the device driven by the concentration gradient. Simultaneously, due to evaporation, water molecules will migrate directionally, selectively driving mobile ions (primarily Cl-). - They move from the high concentration end to the low concentration end through microchannels. Under the continuous driving force of evaporation, the movement of these ions is also accompanied by reverse ion diffusion, electric field-driven drift and other related processes, eventually reaching dynamic equilibrium and forming a stable electric field.

[0075] Example 4

[0076] The IA-HVG devices prepared according to the method in Example 1 were connected in series or in parallel, and their performance was tested (test conditions: 25°C, 70% humidity).

[0077] Three IA-HVG devices, each with 1.5 mL of 20% LiCl solution added, were connected to a digital source oscilloscope to test the voltage. The same three devices were also connected to the same oscilloscope to test the current. The results are as follows: Figure 14 a and Figure 14 As shown in b, when three IA-HVG devices are connected in series, the Voc can reach 1.51V, while when three IA-HVG devices are connected in parallel, the Voc is about 79mA. This indicates that integration can effectively improve the power generation performance of the IA-HVG bifunctional carbon-based aerogel water photovoltaic device.

[0078] Six IA-HVG devices, each with 1.5 mL of 20% LiCl solution added dropwise, were connected in series with wires and then connected to an electronic display screen. The results are as follows: Figure 14As shown in Figure c, six devices connected in series can drive an electronic display screen with special markings. Furthermore, the IA-HVG device is highly sensitive to the aquatic environment; when seawater is introduced, the device can respond quickly and issue an alarm (see Figure c). Figure 14 d).

[0079] An IA-HVG device with 1.5 mL of 20% LiCl solution added was connected to capacitors of different capacitances via wires to test the power supply performance of the aerogel watervolt device for capacitors of different capacitances. The results show that the power generated by the IA-HVG device can be directly stored in commercial capacitors; for example... Figure 14 As shown in e, a single IA-HVG device can charge 0.47F, 0.5F, and 1.0F capacitors to 0.5V in 45 seconds.

[0080] Two IA-HVG devices, each with 1.5 mL of 20% LiCl solution added dropwise, were connected in series with a wire and then connected to a capacitor. The performance of the aerogel water-voltaic device in series charging a commercial capacitor was tested. The results are as follows: Figure 14 As shown in f, two IA-HVG units connected in series can charge 0.5F and 1.0F capacitors to 1V in 75 seconds.

[0081] Example 5

[0082] Seawater was placed in a small beaker. Foam was placed on the seawater, and air-supported paper was laid on the foam. The IA-HVG device prepared in Example 1 was then placed on the air-supported paper to construct a seawater desalination experimental device. The desalination performance of the IA-HVG device on seawater was tested (under the conditions of 25°C and 70% humidity). Figure 15 A schematic diagram of the seawater desalination experimental device is shown.

[0083] Figure 15 Figure b shows a comparison of the surface temperature of the IA-HVG device under different illumination conditions. As can be seen from the figure, with the increase of light intensity, the surface temperature of the IA-HVG increases from 31.5℃ under 0.5 solar intensity to 42.1℃ under 2 solar intensity within 600 seconds.

[0084] Figure 15 c is a graph showing the mass change of seawater under different light intensities; Figure 15 Figure d shows the evaporation rate of seawater under different light intensities. It can be seen that, due to its high light absorption capacity and excellent photothermal conversion performance, the IA-HVG device achieves a water evaporation rate of 1.76 kg·m³ under one solar irradiance. -2 h -1 .

[0085] In addition, experimental setups were constructed with only air-laid paper and only foam as comparisons. The surface temperature and evaporation rate of the air-laid paper and foam, serving as the water transport layer and support layer respectively, were measured under illumination of one sun (one sun's illumination intensity is 1000 watts per square meter). The results showed that their surface temperature and evaporation rate were both lower than those of the IA-HVG device under the same illumination intensity (see...). Figure 15 e and Figure 15 f).

[0086] like Figure 15 As shown in e, after seawater is desalinated using the IA-HVG device, the Na in the desalinated condensate... + Mg 2+ K + and Ca 2+ The concentration of salinity is two orders of magnitude lower than that of the original seawater, and its salinity meets the drinking water standards set by the World Health Organization (WHO) and the U.S. Environmental Protection Agency (EPA).

[0087] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a bifunctional carbon-based aerogel, characterized in that, Chitosan, NCNT dispersion, calcium carbonate, anhydrous acetic acid, and deionized water were mixed and stirred thoroughly in a water bath to obtain a composite gel. Acetic acid was added to the composite gel to carry out the reaction, and then lyophilized to obtain a bifunctional carbon-based aerogel.

2. The method for preparing a bifunctional carbon-based aerogel according to claim 1, characterized in that, The mass ratio of chitosan, NCNT dispersion, calcium carbonate, anhydrous acetic acid and deionized water is 1:36:1:0.5:60, and the NCNT content in the NCNT dispersion is 10wt%.

3. The method for preparing a bifunctional carbon-based aerogel according to claim 1, characterized in that, The water bath temperature is 37℃.

4. The method for preparing a bifunctional carbon-based aerogel according to claim 1, characterized in that, The ratio of composite gel to acetic acid is 9g:1.5mL.

5. The method for preparing a bifunctional carbon-based aerogel according to claim 1, characterized in that, The reaction temperature for adding acetic acid is 37°C.

6. A water-based photovoltaic device, characterized in that, The water-voltaic device is prepared based on the preparation method described in any one of claims 1-5, and it is composed of bifunctionalized carbon-based aerogel, aluminum electrode, and copper electrode.

7. A water-based photovoltaic device according to claim 6, characterized in that, Chitosan, NCNT dispersion, calcium carbonate, anhydrous acetic acid, and deionized water were mixed and stirred thoroughly in a water bath to obtain a composite gel. The composite gel was filled into a container and aluminum and copper electrodes were inserted. Acetic acid was then added to the composite gel to carry out the reaction. After the reaction, the mixture was freeze-dried to obtain a water-voltaic device.

8. A water-based photovoltaic device according to claim 7, characterized in that, The insertion depth of the aluminum electrode in the composite gel is greater than that of the copper electrode in the composite gel.

9. A water-based photovoltaic device according to claim 7, characterized in that, The freeze-drying temperature is -70℃ to -60℃, and the freeze-drying time is 3 hours.

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