Biomass hydrothermal char / ti3c2t x Heterostructured catalyst, method for preparing the same, use thereof, and photoelectrocatalytic cathode

Abstract

The application provides a biomass hydrothermal carbon / Ti3C2T x Heterostructure catalyst, preparation method, application and photoelectrocatalytic cathode, belong to photoelectrocatalytic water treatment technical field.The preparation method includes: biomass raw material particles are dispersed in aqueous solution containing acid and cationic dispersant to carry out hydrothermal reaction, and surface modified biomass hydrothermal carbon is obtained;Ti3C2T x Material and biomass hydrothermal carbon are dispersed in mixed solvent of alcohol and water to obtain dispersion system, the pH of the dispersion system is adjusted to 4.1-6.7, and the composite is carried out under intermittent pulse ultrasonic condition, so that the biomass hydrothermal carbon is inserted into Ti3C2T x Layer, and the biomass hydrothermal carbon / Ti3C2T x Heterostructure catalyst is obtained after drying.The problems of Ti3C2T x Sheet layer easy to stack, small interlayer spacing, low specific surface area, insufficient active site exposure and limited photoelectrocatalytic oxygen reduction efficiency are solved.

Description

Technical Field

[0001] This invention belongs to the field of photoelectrocatalytic water treatment technology, specifically relating to a biomass hydrothermal carbon-modified Ti3C2T x Heterogeneous photoelectrocatalytic cathode catalysts, their preparation methods, and applications. Background Technology

[0002] With accelerated industrialization, changing lifestyles, and population growth, the discharge of various wastes and pollutants continues to increase, causing water, soil, and air pollution. These pollutants can enter the human body through environmental migration and bioaccumulation in the food chain, threatening ecological security and human health. Antibiotics and other recalcitrant organic pollutants, due to their high stability and residue risk, have become a significant issue in water environment management.

[0003] Advanced oxidation technology can generate hydroxyl radicals (·OH) and superoxide radicals (·O2) in situ. - Reactive oxygen species such as ·OH are used to achieve efficient degradation and deep mineralization of antibiotics. ·OH possesses extremely strong oxidizing power, capable of non-selectively attacking the molecular structure of organic pollutants, making it a key reactive species for efficient antibiotic degradation and mineralization. Electro-Fenton and photoelectric Fenton technologies typically generate H2O2 in situ via a cathode oxygen reduction reaction, which is then further activated to generate ·OH, thus avoiding the transportation, storage, and safety issues associated with externally added H2O2. However, traditional systems often rely on the two-electron oxygen reduction pathway to generate H2O2, which then requires diffusion and secondary activation to produce ·OH. This process is complex, resulting in significant H2O2 loss, low activation efficiency, easy dissolution of metal ions, and a narrow pH range, making it difficult to achieve efficient pollutant degradation.

[0004] Photoelectrocatalysis combines the advantages of photocatalysis and electrocatalysis. Under an applied electric field, it can promote the separation and migration of photogenerated carriers and enhance the efficiency of reactive oxygen species generation by having photogenerated electrons participate in the oxygen reduction reaction. Therefore, developing photoelectrocatalytic cathode catalysts with efficient electron transport capabilities, stable interface structures, and tunable oxygen reduction selectivity is of great significance for achieving in-situ generation of ·OH from 3-electron oxygen reduction.

[0005] Ti3C2T x As a typical two-dimensional layered MXene material, it possesses excellent electrical conductivity, abundant surface end groups, good hydrophilicity, and electron transport capabilities, making it a promising candidate for photoelectrocatalytic cathode materials. However, the original Ti3C2T... x Strong van der Waals forces exist between the layers, making them prone to stacking, curling, and aggregation. This results in small interlayer spacing, low specific surface area, insufficient exposure of active sites, and limited electrolyte mass transfer, thus restricting their catalytic performance in oxygen reduction reactions and ·OH generation processes. Existing Ti3C2T xModification methods mainly include chemical intercalation, mechanical exfoliation, metal oxide loading, and carbon material composites. While chemical intercalation can expand the thickness of Ti3C2T to some extent... x Interlayer spacing is important, but intercalation agents are prone to residue, and the expanded layer structure lacks stability, easily leading to secondary stacking. Mechanical exfoliation has poor controllability, easily causing layer breakage and increased defects. Metal or metal oxide loading has high costs, easy dissolution of metal ions, and risks of secondary pollution. Conventional carbon materials such as graphene, carbon nanotubes, and activated carbon are not suitable for use with Ti3C2T. x Most of them are simple physical mixtures with weak interfacial bonding, making them difficult to bond in Ti3C2T. x The formation of stable intercalation support structures between the layers makes it difficult to effectively regulate the oxygen reduction reaction pathway and promote the in-situ generation of ·OH. Summary of the Invention

[0006] (a) Purpose of the invention To solve Ti3C2T x To address the problems of easy stacking of layers, small interlayer spacing, low specific surface area, insufficient exposure of active sites, and limited photoelectrocatalytic oxygen reduction efficiency, this invention provides a biomass hydrothermal char / Ti3C2T. x Heterogeneous catalysts, their preparation methods, applications, and photoelectrocatalytic cathodes.

[0007] (II) Technical Solution To address the aforementioned problems, this invention provides a biomass hydrothermal char / Ti3C2T x Methods for preparing heterostructured catalysts include: Step 1: Disperse biomass raw material particles in an aqueous solution containing acid and cationic dispersant and carry out a hydrothermal reaction to obtain surface-modified biomass hydrothermal char. Step 2: Place Ti3C2T x The surface-modified biomass hydrothermal char obtained in step 1 was dispersed in a mixed solvent of alcohol and water to obtain a dispersion system. The pH of the dispersion system was adjusted to 4.1–6.7, and compounding was performed under intermittent pulsed ultrasonic conditions to allow the biomass hydrothermal char to insert into Ti3C2T. x Between layers, after drying, biomass hydrothermal char / Ti3C2T is obtained. x Heterogeneous catalysts.

[0008] Specifically, in this embodiment of the invention, the pH value is the apparent pH value measured using a pH meter.

[0009] This invention utilizes the synergistic regulation of biomass hydrothermal char with dilute acid and cationic dispersants to induce a positively charged surface in an alcohol-water mixed solvent with a pH of 4.1–6.7, and to react with Ti3C2T, which exhibits a negatively charged surface under the same conditions. xThey are tightly bound together through electrostatic attraction; simultaneously, the oxygen-containing functional groups on the surface of biomass hydrothermal char and Ti3C2T are utilized. x Hydrogen bonding between surface end groups enables the irregularly shaped spherical biomass hydrothermal carbon to be stably inserted into and supported on Ti3C2T. x Between the layers, interfaces with Schottky heterojunction characteristics are constructed, thereby increasing the interlayer spacing, improving the specific surface area, enabling directional migration of interfacial electrons, regulating the oxygen reduction pathway, and achieving efficient in-situ generation of ·OH, ultimately improving the photoelectrocatalytic degradation efficiency of tetracycline-containing wastewater.

[0010] Specifically, the concentration of acid in the aqueous solution is 0.5–3 mol / L; Preferably, the concentration of acid in the aqueous solution is 0.8–1.5 mol / L.

[0011] Within this range, it can promote the hydrolysis and hydrothermal carbonization of biomass raw materials, while avoiding excessive carbonization of particles or reduction of surface functional groups due to excessively high acid concentration, thus facilitating the formation of biomass hydrothermal carbon with relatively uniform particle size and good dispersibility.

[0012] The concentration of the cationic dispersant is 0.001–0.05 g / mL; Preferably, the concentration of the cationic dispersant is 0.005–0.03 g / mL. Within this range, it can both regulate the surface charge of biomass hydrothermal char and improve particle dispersibility, while avoiding excessive dispersant leading to increased residue or hindered interfacial contact. The ratio of the biomass feed pellets to the aqueous solution is 1 g: (8-20) mL; The biomass raw material is selected from at least one of corn cob, grapefruit peel, and rice husk; The acid is at least one selected from sulfuric acid, hydrochloric acid, nitric acid, acetic acid, phosphoric acid, formic acid, citric acid, and oxalic acid. The cationic dispersant is a quaternary ammonium salt cationic surfactant; The quaternary ammonium salt cationic surfactant is selected from at least one of hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, dodecyltrimethylammonium bromide, octadecyltrimethylammonium chloride, dodecyltrimethylammonium chloride, tetradecyltrimethylammonium bromide, tetradecyltrimethylammonium chloride, and octadecyltrimethylammonium bromide.

[0013] Furthermore, the specific conditions for the hydrothermal reaction described in step 1 include: The temperature is 160–220 °C, and the reaction time is 12–48 h.

[0014] Specifically, in step 2, the surface-modified biomass hydrothermal char and Ti3C2T x The mass ratio of the materials is 0.5 to 6:1; The alcohol in the mixed solvent of alcohol and water is at least one of anhydrous ethanol, methanol, isopropanol, n-propanol, ethylene glycol, and glycerol; The volume ratio of alcohol to water is 20:1 to 1:1; When alcohol and water are mixed in this ratio, the mixed solvent combines the high polarity of the aqueous phase and the low surface tension of the alcohol phase, thus maintaining the properties of Ti3C2T. x The surface functional groups are solvated and their charges are stabilized, which improves the wetting and dispersibility of biomass hydrothermal char in the dispersion system.

[0015] Preferably, the pH of the dispersion system is 5 to 6.

[0016] Within this pH range, Ti3C2T x The surface-modified biomass hydrothermal char exhibits a larger zeta potential difference, resulting in a stronger and more stable electrostatic attraction, which promotes the uniform insertion and support of the biomass hydrothermal char onto Ti3C2T. x Interlayer bonding further improves intercalation efficiency, interfacial tightness, and heterogeneous structure stability.

[0017] Specifically, step 2, which involves combining the components under intermittent pulsed ultrasound conditions, includes: The ultrasonic amplitude is set to 20%–60%; the pulse working mode is: alternating between working for 10–50 seconds and intermittent for 10–50 seconds, with a total ultrasonic time of 20 min–2 h.

[0018] Preferably, the ultrasonic amplitude is set to 35%–50%, the working time is 30–40 s, the interval time is 30–40 s, and the total ultrasonic time is 40–70 min. Under these ultrasonic conditions, the pulse mode can avoid the problem of local overheating in continuous ultrasound. It can both peel off and loosen the interlayer structure through ultrasonic cavitation, providing an embedding channel for biomass hydrothermal carbon, and prevent Ti3C2T x Excessive fragmentation of the lamellae leads to structural collapse.

[0019] Specifically, in step 2, biomass hydrothermal char and Ti3C2T x The mass ratio of the materials is 0.5 to 6:1.

[0020] Preferably, in step 2, the biomass hydrothermal char and Ti3C2T x The mass ratio of the materials is 2.8–3.2:1. When the two are in this ratio, the specific surface area of ​​the catalyst can reach 42 m². 2 It has a concentration of over / g and a significantly improved ·OH generation capacity.

[0021] Preferably, the biomass hydrothermal char / Ti3C2T xThe specific surface area of ​​the heterostructure catalyst is 12–45 m². 2 / g, with a pore size of 10–15 nm.

[0022] In one specific embodiment, a biomass hydrothermal char / Ti3C2T x A method for preparing a heterostructured photoelectrocatalytic cathode catalyst includes the following steps: Step 1: Preparation of Ti3C2T x Material Ti3AlC2 powder was etched using HF aqueous solution to selectively remove the Al layer. After etching, the powder was washed with deionized water by centrifugation until the supernatant was nearly neutral. Then, it was subjected to intermittent pulsed ultrasonic treatment using an ultrasonic cell disruptor under ice bath conditions. Finally, it was centrifuged and dried to obtain Ti3C2T. x Material.

[0023] Specifically, the HF aqueous solution has a mass fraction of 30% to 50%.

[0024] Specifically, the mass ratio of Ti3AlC2 to the volume ratio of the HF aqueous solution is 1–5 g: 10–100 mL.

[0025] Specifically, the etching temperature is 25–50 °C, and the etching time is 12–36 h.

[0026] Specifically, the centrifugation speed is 3000-8000 rpm and the centrifugation time is 20-90 min.

[0027] Specifically, the rated power of the ultrasonic cell disruptor is 120-140 W and the frequency is 15-25 kHz; the ultrasonic amplitude of the intermittent pulse ultrasound is 20% to 60%, the pulse working mode is alternating between 10 to 50 seconds of operation and 10 to 50 seconds of interval, and the total ultrasound time is 20 min to 2 h.

[0028] Specifically, the total ultrasound time mentioned in this embodiment of the invention refers to the sum of working time and interval time.

[0029] Furthermore, the drying temperature is 30–60 °C, and the drying time is 8–72 h.

[0030] Step 2: Preparation of biomass hydrothermal char The biomass raw material is crushed and dispersed in a mixed solution containing acid and cationic dispersant. After stirring evenly, it is transferred to a hydrothermal reactor for hydrothermal reaction. After the reaction is completed, it is cooled to room temperature, washed and dried to obtain irregular spherical biomass hydrothermal char.

[0031] Specifically, the acid concentration in the mixed solution is 0.5–3 mol / L.

[0032] Specifically, the concentration of the cationic dispersant is 0.001–0.05 g / mL.

[0033] Specifically, the biomass to mixed solution ratio is 1 g: 8-20 mL.

[0034] Specifically, the hydrothermal reaction temperature is 160–220 °C, and the hydrothermal reaction time is 12–48 h.

[0035] Specifically, the drying temperature is 50–80 °C, and the drying time is 12–36 h.

[0036] Step 3: Preparation of biomass hydrothermal char modified Ti3C2T x catalyst The Ti3C2T obtained in step 1 x The biomass hydrothermal char obtained in step 2 was dispersed in a mixed solvent of alcohol and water at a certain mass ratio. The pH was adjusted to 4.1–6.7 by adding acid, followed by intermittent pulsed ultrasonic treatment using an ultrasonic cell disruptor under ice bath conditions. After compounding, the mixture was filtered and dried to obtain biomass hydrothermal char intercalation-supported modified Ti3C2T with Schottky heterojunction characteristics. x Photoelectrocatalytic cathode catalyst.

[0037] Specifically, the biomass hydrothermal char and Ti3C2T x The mass ratio is 6:1 to 0.5:1.

[0038] Specifically, the alcohol is one or more of anhydrous ethanol, methanol, isopropanol, n-propanol, ethylene glycol, and glycerol.

[0039] The acid added to adjust the pH value is at least one of sulfuric acid, nitric acid, acetic acid, phosphoric acid, formic acid, oxalic acid, and citric acid. Specifically, the ultrasonic cell disruptor has a rated power of 130 W and a frequency of 20 kHz; the intermittent pulse ultrasound has an ultrasonic amplitude set to 20%–60%, and the pulse working mode alternates between working for 10–50 s and intermittent for 10–50 s, with a total ultrasound time of 20 min–2 h.

[0040] Furthermore, the drying temperature is 40–80 °C, and the drying time is 4–12 h.

[0041] In a second aspect, the present invention provides a biomass hydrothermal char / Ti3C2T prepared by any of the methods described above. x Heterogeneous catalysts.

[0042] The catalysts and preparation methods provided by this invention correspond one-to-one, and the relevant descriptions can be found in the catalyst preparation methods, which will not be repeated here.

[0043] A third aspect of the present invention provides a photoelectrocatalytic cathode, wherein the catalyst is prepared by any of the methods described above.

[0044] In one specific embodiment, the method for preparing the integrated catalytic cathode includes: The catalyst, conductive carbon black, and concentrated polytetrafluoroethylene dispersion were mixed in a mass ratio of 7:2:1 to 8:1:1. After adding 2 to 10 mL of ethanol, the mixture was ground thoroughly to ensure uniform mixing. The solvent was then evaporated by heating until a paste was formed. The resulting paste was pressed and bonded to a 100-mesh stainless steel mesh, cut into 2 cm × 3 cm pieces, and dried in an oven at 80 ℃ for 12 h to obtain an integrated catalytic cathode.

[0045] Specifically, the polytetrafluoroethylene concentrated dispersion is an aqueous dispersion, and the mass fraction of polytetrafluoroethylene in the polytetrafluoroethylene concentrated dispersion is 60 wt%.

[0046] Specifically, during the photoelectrocatalytic degradation process, the catalytic cathode current density is controlled to be 0.1–2.5 mA / cm². 2 The degradation time is 30–180 min.

[0047] The catalyst is suitable for photoelectrocatalytic cathode systems. It can regulate oxygen reduction and subsequent H2O2 activation processes under visible light irradiation and an applied electric field, making the system as a whole tend to approach the reaction pathway of three-electron transfer, thereby generating hydroxyl radicals in situ and achieving efficient degradation of tetracycline-containing wastewater.

[0048] The fourth aspect of the present invention provides a biomass hydrothermal char / Ti3C2T prepared by any of the methods described above. x Application of at least one of the heterostructure catalysts and the above-mentioned photoelectrocatalytic cathodes in the photoelectrocatalytic removal of antibiotics from wastewater.

[0049] The antibiotic is preferably at least one of tetracycline antibiotics, quinolone antibiotics, and sulfonamide antibiotics, with tetracycline being the most preferred; Specifically, a two-electrode photoelectrocatalytic reaction system was constructed using a photoelectrocatalytic cathode as the working cathode and a platinum wire as the counter anode. Na2SO4 was used as the supporting electrolyte, and the photoelectrocatalytic cathode was constructed using biomass hydrothermal carbon / Ti3C2T. x Heterogeneous catalysts.

[0050] The pH value of the wastewater is preferably 2 to 12.

[0051] Compared with the prior art, the present invention has the following superior effects: This invention utilizes the synergistic regulation of dilute acid and cationic dispersants to control the formation and surface properties of biomass hydrothermal char, enabling the formation of spherical or near-spherical biomass hydrothermal char with relatively uniform morphology and good dispersibility during the hydrothermal carbonization process of lignocellulose raw materials. This method simultaneously adjusts its surface charge and surface functional group distribution, resulting in biomass hydrothermal char with oxygen-containing functional groups such as hydroxyl and carboxyl groups on its surface. By combining the biomass hydrothermal char with Ti3C2T... x The powder was dispersed in a mixed solvent of alcohol and water, and the pH was adjusted to 4.1-6.7 to make the surface of the biomass hydrothermal char exhibit a tendency towards positive charge and Ti3C2T. x The material surface exhibits a negative charge tendency, leading to electrostatic attraction between the two. Because the surface of biomass hydrothermal char contains oxygen-containing functional groups such as hydroxyl and carboxyl groups, it interacts with Ti3C2T. x The -O, -OH, -F end groups on the surface form hydrogen bonds and other interfacial interactions, allowing the biomass hydrothermal carbon to be distributed on Ti3C2T. x The layers act as intercalation supports, thereby alleviating the problems associated with Ti3C2T. x Layer stacking improves the pore structure and mass transfer properties of materials.

[0052] The biomass hydrothermal char / Ti3C2T obtained by this invention x The specific surface area of ​​the composite catalyst can reach 12 m². 2 / g or higher (e.g., BT-3 can reach 42.03 m) 2 / g, compared to Ti3C2T x 5.31 m 2 The increase of approximately 691.5% (g / g) indicates that the composite structure can significantly improve the pore structure and active site exposure conditions of the material, which is beneficial to improving the photoelectrocatalytic degradation performance.

[0053] The biomass hydrothermal char / Ti3C2T obtained by this invention x The composite catalyst has good interfacial charge transfer ability and oxygen reduction pathway regulation ability. It can promote the in-situ activation of H2O2 to generate ·OH, improve the ·OH generation efficiency, and thus enhance the photoelectrocatalytic degradation performance of tetracycline wastewater. Attached Figure Description

[0054] Figure 1 These are SEM images of the BT-3 catalyst obtained in Example 1 of this invention at different magnifications, wherein... Figure 1 a and b are SEM images at different magnifications; Figure 2 The Ti3C2T obtained in Comparative Example 1 of this invention x SEM images at different magnifications, where, Figure 2 a and b are SEM images at different magnifications; Figure 3 The Ti3C2T obtained in Comparative Example 1 of this invention x TEM images and corresponding elemental energy dispersive spectroscopy (EDS) spectra of the HTC catalyst obtained in Comparative Example 2 and the BT-3 catalyst obtained in Example 1, wherein, Figure 3 a is Ti3C2T x TEM image, Figure 3 b is the TEM image of the HTC obtained in Comparative Example 2. Figure 3 c is a TEM image of the BT-3 catalyst obtained in Example 1. Figure 3 d~ Figure 3 h is the energy spectrum distribution of elements such as Ti, F, C, and O in the BT-3 catalyst obtained in Example 1; Figure 4 The Ti3C2T obtained in Comparative Example 1 of this invention x The Zeta potential variation curves of HTC under different pH conditions obtained in Comparative Example 2; Figure 5 The Ti3C2T obtained in Comparative Example 1 of this invention x X-ray diffraction patterns of the HTC catalyst obtained in Comparative Example 2 and the BT-3 catalyst obtained in Example 1; Figure 6 The Ti3C2T obtained in Comparative Example 1 of this invention x FT-IR spectra of HTC obtained in Comparative Example 2 and BT-3 catalyst obtained in Example 1; Figure 7 The Ti3C2T obtained in Comparative Example 1 of this invention x Nitrogen adsorption-desorption isotherms and pore size distribution curves of HTC obtained in Comparative Example 2 and BT-3 catalyst obtained in Example 1; Figure 8 The Ti3C2T obtained in Comparative Example 1 of this invention x Steady-state photoluminescence spectra of the HTC catalyst obtained in Comparative Example 2 and the BT-3 catalyst obtained in Example 1; Figure 9 The Ti3C2T obtained in Comparative Example 1 of this invention x XPS spectra of the BT-3 catalyst obtained in Example 1, wherein, Figure 9 a is Ti 2p Spectrum Figure 9 b is F 1s Spectrum; Figure 10 The Ti3C2T obtained in Comparative Example 1 of this invention x RRDE linear sweep voltammetry curves and electron transfer number analysis diagrams of the BT-3 catalyst obtained in Example 1; Figure 11The catalysts BT-3, BT-2.5, BT-3.5, and BT-4 obtained in Examples 1-4 of this invention, and the Ti3C2T catalyst obtained in Comparative Example 1, are examples of catalysts of this invention. x Comparison of the ·OH and H2O2 generation performance of HTC obtained in Comparative Example 2, where, Figure 11 a represents the curve of ·OH concentration changing over time. Figure 11 b is a comparison chart of the ·OH formation rate constants. Figure 11 c represents the curve of H2O2 concentration changing over time. Figure 11 d is a comparison chart of the H2O2 formation rate constants; Figure 12 The photoelectrocatalytic degradation performance curves of tetracycline by the BT-3 catalyst obtained in Example 1 of this invention under different initial pH conditions are shown. Figure 13 The figures show the photoelectrocatalytic degradation performance curves of tetracycline by the BT-DTAB catalyst obtained in Example 5 and the BT-CTAB-free catalyst obtained in Comparative Example 3. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0056] The raw materials and reagents used in the embodiments and comparative examples of this invention are all conventional commercially available products; The stainless steel mesh has a diameter of 100 mesh. Ti3AlC2 powder was purchased from Anhui Zesheng Technology Co., Ltd., with a particle size of 400 mesh and a purity of 95%.

[0057] Example 1 This embodiment provides a biomass hydrothermal carbon intercalation-supported modified Ti3C2T x The preparation method of heterostructured photoelectrocatalytic cathode catalyst includes the following steps: Step 1: Preparation of biomass hydrothermal char Corn cobs were pulverized to 200 mesh. 3 g of the pulverized corn cobs were weighed and dispersed in 40 mL of an aqueous solution containing hexadecyltrimethylammonium bromide (CTAB) and sulfuric acid. The sulfuric acid concentration in the aqueous solution was 1 mol / L, and the hexadecyltrimethylammonium bromide concentration was 0.025 g / mL. After magnetic stirring for 30 min, the mixture was transferred to a 100 mL hydrothermal reactor and hydrothermally reacted at 200 ℃ for 18 h. After the reaction, the mixture was cooled to room temperature and repeatedly washed with deionized water until the pH reached 6.5. It was then dried in an oven at 80 ℃ for 24 h to obtain modified irregular spherical biomass hydrothermal char.

[0058] Step 2: Ti3C2T x Material preparation 2 g of Ti3AlC2 powder was weighed and added to 40 mL of 40% HF aqueous solution. The mixture was etched in a constant temperature water bath at 40 °C for 24 h. After etching, the product was washed with deionized water by centrifugation until the pH of the supernatant reached 6. The centrifugation speed was 3500 rpm and the centrifugation time was 60 min. Subsequently, intermittent pulsed ultrasound was performed using an ultrasonic cell disruptor with a rated power of 130 W and a frequency of 20 kHz, with an output amplitude of 40%, under ice bath conditions. The pulse working mode alternated between 30 s working and 30 s intermittent intervals, with a total ultrasound time of 1 h. After ultrasound, the mixture was centrifuged again at 5000 rpm for 20 min. The precipitate was collected and dried in a 45 °C oven for 12 h to obtain multilayer Ti3C2T. x Material.

[0059] Step 3: Catalyst Preparation According to the modified biomass hydrothermal carbon and Ti3C2T x The mass ratio is 3:1. Weigh out 0.9 g of biomass hydrothermal char and 0.3 g of Ti3C2T. x The two were dispersed in a mixed solvent of 30 mL ethanol and water, wherein the volume ratio of ethanol to water was 9:1, and the apparent pH of the resulting dispersion system was adjusted to 6 using a 0.1 mol / L dilute sulfuric acid solution.

[0060] Subsequently, an ultrasonic cell disruptor with a rated power of 130 W and a frequency of 20 kHz was used, with an output amplitude of 50%, and intermittent pulsed ultrasound was performed under ice bath conditions. The pulse working mode alternated between 30 s working and 30 s intermittent intervals, with a total ultrasound time of 1 h. After ultrasound, the resulting mixture was filtered, and the resulting filter cake was dried in a 60 ℃ oven for 8 h to obtain biomass hydrothermal carbon-modified Ti3C2T. xThe heterojunction photoelectrocatalytic cathode catalyst is designated BT-3.

[0061] Examples 2-4 The only difference between Examples 2-4 and Example 1 is that in step 3, the biomass hydrothermal char and Ti3C2T... x The mass ratios were adjusted to 2.5:1, 3.5:1, and 4:1, respectively, and the remaining preparation conditions were the same as in Example 1. The resulting catalysts were designated as BT-2.5, BT-3.5, and BT-4, respectively.

[0062] Example 5 The difference between this embodiment and Example 1 lies in the types of dilute acid and cationic dispersant used in step 2. Specifically, the dilute sulfuric acid in step 2 of Example 1 is replaced with a 1 mol / L acetic acid solution, and hexadecyltrimethylammonium bromide is replaced with dodecyltrimethylammonium bromide (DTAB) at a concentration of 0.025 g / mL. The remaining preparation conditions are the same as in Example 1, yielding biomass hydrothermal carbon intercalation-supported modified Ti3C2T. x The heterojunction photoelectrocatalytic cathode catalyst is denoted as BT-DTAB.

[0063] Comparative Example 1 A pure Ti3C2T x The preparation method of the photoelectrocatalytic cathode catalyst only follows step 1 of Example 1, without biomass hydrothermal carbon modification. The specific steps are as follows: 2 g of Ti3AlC2 powder was weighed and added to 40 mL of 40% HF aqueous solution. The mixture was etched in a constant temperature water bath at 40 °C for 24 h. After etching, the product was washed with deionized water by centrifugation until the pH of the supernatant reached 6. The centrifugation speed was 3500 rpm and the centrifugation time was 60 min. Subsequently, intermittent pulsed ultrasound was performed using an ultrasonic cell disruptor with a rated power of 130 W and a frequency of 20 kHz, with an output amplitude of 40%, under ice bath conditions. The pulse working mode alternated between 30 s working and 30 s intermittent intervals, for a total ultrasound time of 1 h. After ultrasound, the mixture was centrifuged again at 5000 rpm for 20 min. The precipitate was collected and dried in a 45 °C oven for 12 h to obtain multilayer Ti3C2T. x Material.

[0064] Comparative Example 2 A method for preparing a pure hydrothermal carbon photoelectrocatalytic cathode catalyst, which only involves step 2 of Example 1, is as follows: Corn cobs were crushed to 200 mesh. 3 g of the crushed corn cobs were weighed and dispersed in 40 mL of a dilute sulfuric acid solution containing hexadecyltrimethylammonium bromide. The concentration of the dilute sulfuric acid was 1 mol / L, and the concentration of hexadecyltrimethylammonium bromide was 0.025 g / mL. After magnetic stirring for 30 min, the mixture was transferred to a 100 mL hydrothermal reactor and hydrothermally reacted at 200 ℃ for 18 h. After the reaction was completed, the mixture was cooled to room temperature, repeatedly washed with deionized water until neutral, and then dried in an oven at 80 ℃ for 24 h to obtain positively charged irregular spherical biomass hydrothermal char, denoted as HTC.

[0065] Comparative Example 3 A biomass hydrothermal char modified Ti3C2T without the addition of CTAB x The catalyst preparation method differs from that in Example 1 only in that CTAB is not added in step 2. The remaining steps are completely consistent with those in Example 1, resulting in a modified catalyst without CTAB, denoted as BT-CTAB-free.

[0066] Application Example 1 The photoelectrocatalytic degradation of tetracycline was tested using the BT-3 catalyst obtained in Example 1 according to the following method: 0.21 g of BT-3 catalyst was weighed and mixed with conductive carbon black and a concentrated dispersion of polytetrafluoroethylene (PTFE) at a mass ratio of 7:2:1, wherein the PTFE concentration contained 60 wt% PTFE. Then, 5 mL of ethanol was added, and the mixture was thoroughly ground for 30 min to ensure homogeneity. The solvent was then evaporated by heating until a paste was formed. The resulting paste was pressed onto a 100-mesh stainless steel mesh and compacted using a tablet press to ensure a tight fit. It was then cut into 2 cm × 3 cm pieces and dried in an oven at 80 ℃ for 12 h to obtain an integrated catalytic cathode.

[0067] A dual-electrode photoelectrocatalytic reaction system was constructed using the prepared integrated catalytic cathode as the working cathode and platinum wire as the counter anode. 100 mL of a 10 mg / L tetracycline solution was used as the target pollutant solution, and 0.05 M Na₂SO₄ was added as the supporting electrolyte. Air was then introduced for aeration for 30 min. Subsequently, the mixture was stirred in the dark for 30 min to allow the tetracycline to reach adsorption-desorption equilibrium on the electrode surface. A 10 W LED light source was then turned on, and an external DC power supply was connected simultaneously. The cathode current density was controlled at 1.0 mA / cm² in constant current mode. 2 The reaction continues for 60 minutes.

[0068] The test results show that under the initial natural pH conditions of tetracycline, the BT-3 catalyst achieved a degradation rate of 99.8% for tetracycline after 60 min of reaction, demonstrating excellent photoelectrocatalytic degradation performance.

[0069] Furthermore, the photoelectrocatalytic degradation performance of BT-3 catalyst for tetracycline was investigated under different initial pH conditions. The initial pH of the tetracycline solution was adjusted to 2, 4, 6, 8, 10, 12, and 13, respectively. Other reaction conditions were the same as those described above.

[0070] Test results showed that when the initial pH was 2, 4, 6, 8, 10, 12, and 13, the tetracycline degradation rates reached 93.1%, 99.9%, 98.6%, 99.3%, 98.4%, 97.9%, and 80.2%, respectively. This indicates that the BT-3 catalyst exhibits excellent tetracycline degradation activity over a wide pH range.

[0071] Application Example 2 This application example is used to evaluate the photoelectrocatalytic degradation performance of tetracycline by the BT-DTAB catalyst obtained in Example 5 and the BT-CTAB-free catalyst in Comparative Example 3.

[0072] In this application example, the preparation method of the integrated catalytic cathode is basically the same as that in application example 1, except that the catalysts used are the BT-DTAB catalyst obtained in example 5 and the BT-DTAB-free catalyst obtained in comparative example 3, respectively.

[0073] The test method for photoelectrocatalytic degradation of tetracycline is basically the same as that in Application Example 1, except that the pH of the tetracycline solution in this application example was not adjusted, i.e., the photoelectrocatalytic degradation test was carried out under its initial natural pH of 7.2.

[0074] Test results showed that the BT-DTAB and BT-CTAB-free catalysts achieved tetracycline degradation rates of 94.6% and 74.0%, respectively, within 60 min of photoelectrocatalytic reaction.

[0075] Application Example 3 This application example is used to test the cumulative concentrations of ·OH and H2O2 in different catalysts during the photoelectrocatalysis process.

[0076] The preparation method of the integrated catalytic cathode in this application example is basically the same as that in application example 1, except that the catalysts used are BT-3, BT-2.5, BT-3.5, and BT-4 obtained in examples 1 to 4, and Ti3C2T obtained in comparative example 1. x The HTC obtained from Comparative Example 2.

[0077] The cumulative production of ·OH was quantitatively detected using benzoic acid as a probe molecule. Benzoic acid can react with ·OH to generate p-hydroxybenzoic acid. The concentration of p-hydroxybenzoic acid was determined by high performance liquid chromatography, and the cumulative concentration of hydroxyl radicals generated in the system was estimated based on the amount of p-hydroxybenzoic acid generated, with a conversion factor of 5.87.

[0078] The high-performance liquid chromatography (HPLC) test conditions were as follows: a C18 column with dimensions of 250 mm × 4.6 mm was used; a UV detector was used for detection, with an injection volume of 20 μL; the mobile phase was 20% acetonitrile and 80% phosphoric acid aqueous solution, with the phosphoric acid aqueous solution having a pH of 3; the flow rate was 1 mL / min, and the detection wavelength was 270 nm. The initial concentration of benzoic acid was set at 5 mM.

[0079] The procedure for testing the cumulative concentration of OH is as follows: 0.05 M Na₂SO₄ was added as a supporting electrolyte to 100 mL of a 5 mM benzoic acid aqueous solution, and air was introduced for aeration for 30 min. Subsequently, the mixture was stirred in the dark for 30 min to allow the system to reach adsorption-desorption equilibrium on the electrode surface. Then, a 10 W LED light source was turned on, and an external DC power supply was connected. The cathode current density was controlled at 1.0 mA / cm² in constant current mode. 2 The reaction was continued for 60 min. During the reaction, liquid samples were collected at set time points. The samples were filtered through a 0.22 μm filter membrane, and the concentration of p-hydroxybenzoic acid in the filtrate was determined by high performance liquid chromatography (HPLC). The cumulative concentration of ·OH was then calculated.

[0080] The procedure for testing the cumulative concentration of H2O2 is as follows: Air was introduced into 100 mL of a 0.05 M Na2SO4 aqueous solution and aerated for 30 min. Subsequently, a 10 W LED light source was turned on, and an external DC power supply was simultaneously connected. The cathode current density was controlled at 1.0 mA / cm² in constant current mode. 2 The reaction was continued for 60 min. During the reaction, liquid samples were collected at set time points. After filtering the obtained samples through a 0.22 μm filter membrane, the H2O2 concentration was determined using titanium salt spectrophotometry. Specifically, 2 mL of the sample to be tested was placed in a colorimetric tube, 2 mL of colorimetric reagent was added, the mixture was shaken well, and allowed to stand for 10 min. After complete color development, the absorbance of the test liquid was measured at a wavelength of 400 nm using UV-Vis spectrophotometry, and the cumulative concentration of H2O2 was calculated based on the H2O2 standard curve.

[0081] The test results showed that BT-2.5, BT-3, BT-3.5, and BT-4 catalysts could all generate a certain amount of ·OH and H2O2 within 60 min of the photoelectrocatalytic reaction. Specifically, the cumulative concentrations of ·OH for BT-2.5, BT-3, BT-3.5, and BT-4 catalysts were 81.7 μmol / L, 118.9 μmol / L, 62.5 μmol / L, and 57.7 μmol / L, respectively; and the cumulative concentrations of H2O2 were 349.5 μmol / L, 136.0 μmol / L, 244.9 μmol / L, and 458.3 μmol / L, respectively.

[0082] In contrast, the pure Ti3C2T x The cumulative ·OH concentration of the catalyst was 26.8 μmol / L, corresponding to a cumulative H2O2 concentration of 119.3 μmol / L; the cumulative ·OH concentration of the pure biomass hydrothermal carbon catalyst was 12.3 μmol / L, corresponding to a cumulative H2O2 concentration of 512.8 μmol / L.

[0083] The above results indicate that biomass hydrothermal char alone has a strong H2O2 generation capacity, but a weak ·OH generation capacity; Ti3C2T alone... x The ability to generate ·OH and H2O2 is limited. However, the biomass hydrothermal carbon intercalation-supported modified Ti3C2T prepared in this invention... x The catalyst can achieve a synergistic effect between in-situ H2O2 generation and activation to generate ·OH, significantly improving the ·OH generation efficiency.

[0084] The products obtained from the examples and / or comparative examples were characterized and analyzed: 1. The morphology and microstructure of the material were characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM): The result is Figure 1 From parts a and b, we can see that Ti3C2T x The substrate exhibits a typical accordion-like layered stacked morphology, with spherical hydrothermal carbon particles distributed and embedded in its lamellar surface and interlayer structure, thereby suppressing Ti3C2T x Layer recombination.

[0085] Depend on Figure 2 As can be seen from parts a and b in Comparative Example 1, pure Ti3C2T was prepared. x The sample exhibits a typical accordion-like layered structure with a relatively regular overall morphology. No other obvious supporting structures were observed between the layers, indicating that the layers are prone to recombination.

[0086] Depend on Figure 3As shown in Figure 3ah, the TEM and elemental distribution characterization results indicate that the pure Ti3C2T prepared in Comparative Example 1... x (Figure 3a) exhibits a typical two-dimensional lamellar morphology, while the HTC prepared in Comparative Example 2 (Figure 3b) is a near-spherical nanoparticle aggregate; in the BT-3 prepared in Example 1 (Figure 3c), HTC nanoparticles are uniformly loaded on Ti3C2T x Between the surface and the layers, the two-phase interface is in close contact; the corresponding elemental distribution spectrum (Figure 3d-h) shows that C, O, F, and Ti elements are uniformly distributed in the material, indicating that HTC particles have been successfully loaded and bonded with Ti3C2T. x The formation of a uniform composite matrix further verifies the successful construction of the heterojunction structure.

[0087] The Zeta potential test method was used to test Ti3C2T x The surface charge of HTC was characterized under different pH conditions: Depend on Figure 4 It can be seen that Ti3C2T x The isoelectric point of Ti3C2T is approximately 4.1, while that of HTC is approximately 6.7. When the pH of the system is between their isoelectric points, Ti3C2T... x The surface zeta potential is negative, indicating a tendency towards negative charge; the surface zeta potential of HTC is positive, indicating a tendency towards positive charge. During the composite process, the pH of the dispersion system was controlled at 4.5–6.5 to allow HTC to react with Ti3C2T. x Maintaining positive and negative charges respectively, thereby promoting HTC's transformation to Ti3C2T x The surfaces and interlayer regions of the lamellae are close together and bonded, increasing the interfacial bonding strength and forming a stable biomass hydrothermal char / Ti3C2T. x Heterogeneous structure.

[0088] The phase structure of the material was determined using X-ray diffraction (XRD). The result is Figure 5 The XRD pattern shows that the characteristic diffraction peaks of the raw material Ti3AlC2 are sharp and have high intensity; after etching, the pure Ti3C2T prepared in Comparative Example 1... x The characteristic peaks such as (104) were significantly weakened or disappeared, while Ti3C2T x The (002) peak shifts to a lower angle, indicating that the aluminum layer was successfully etched and the layered structure was preserved. The HTC sample prepared in Comparative Example 2 shows a broad and diffuse diffraction peak around 21°, corresponding to the characteristic peak of amorphous carbon, indicating that HTC is mainly an amorphous carbon structure. In the BT-3 sample of Example 1, the (002) peak is lower than that of Ti3C2T. xFurther shifting to lower angles confirms that HTC's embedding effectively expands the Ti3C2T. x The interlayer spacing.

[0089] The functional group composition of the material surface and the changes in functional groups after recombination were characterized using Fourier transform infrared spectroscopy (FT-IR). The result is Figure 6 FT-IR spectra show that Ti3C2T x The sample is at approximately 3410 cm. -1 A broad absorption peak appears at approximately 1620 cm⁻¹, corresponding to the stretching vibration of the surface -OH group; at approximately 1620 cm⁻¹... -1 The absorption peak at approximately 561 cm⁻¹ can be attributed to the bending vibrations of adsorbed water or hydroxyl groups. -1 The absorption peak at this point corresponds to the Ti-O bond vibration, indicating that Ti3C2T x The surface contains abundant oxygen-containing functional groups. The HTC sample also exhibits this characteristic at 3410 cm⁻¹. -1 A distinct -OH absorption peak is observed nearby, and at 1701 cm⁻¹ -1 A C=O stretching vibration peak appears at 1610 cm⁻¹. -1 A C=C skeletal vibration peak appeared nearby; in addition, at 1206 cm⁻¹ -1 This can be attributed to COC stretching vibration, 10¹⁵ cm. -1 and 835cm -1 The nearby absorption peaks are related to the vibrations of the furan ring structure, indicating that the hydrothermal carbon contains various oxygen-containing functional groups such as hydroxyl, carbonyl, and furan-like structures. The BT-3 composite sample also retains the Ti3C2T... x The presence of characteristic peaks similar to those of HTC, with no significant shift in peak position, indicates that functional groups of both phases were retained during the composite process, resulting in a stable material structure. This further confirms the presence of characteristic peaks in Ti3C2T. x The successful reunification with HTC.

[0090] The specific surface area and pore structure of the material were characterized using a specific surface area and pore size analyzer and a nitrogen adsorption-desorption test method. The result is Figure 7 The N2 adsorption-desorption isotherms and pore size distribution results show that Ti3C2T x The HTC and BT-3 samples all exhibited typical type IV adsorption isotherm characteristics, indicating the presence of a certain mesoporous structure in the material. Compared to pure Ti3C2T x Compared to HTC, the N2 adsorption capacity of the BT-3 sample was significantly increased, indicating a richer pore structure. BET specific surface area results showed that the specific surface area of ​​BT-3 reached 42.03 m². 2 / g, significantly higher than Ti3C2T x 5.31 m2 / g and HTC's 5.57 m 2 / g. Meanwhile, the average pore size of BT-3 is 12.10 nm, significantly smaller than that of Ti3C2T. x The average pore sizes of Ti3C2T (37.98 nm) and HTC (58.04 nm) indicate that the pore size distribution of the composite material shifts towards smaller mesopores. This result demonstrates that the introduction of HTC can effectively support Ti3C2T. x The lamellar structure inhibits self-stacking, thereby significantly increasing the specific surface area of ​​the material and regulating the pore structure, providing favorable conditions for the exposure of active sites and mass transport during the reaction process.

[0091] The photogenerated carrier recombination behavior and charge separation capability of the material were characterized using a fluorescence spectrometer and photoluminescence (PL) spectroscopy. The result is Figure 8 The photoluminescence (PL) spectrum shows that, under 375 nm excitation, Ti3C2T x Both HTC and HTC exhibit broad emission peaks in the 400–750 nm range, indicating the presence of photogenerated carrier recombination in the material. Among them, pure Ti3C2T... x The PL emission intensity was the highest, with the emission peak mainly concentrated in the region of approximately 480–520 nm, indicating that its photogenerated electron-hole recombination was more significant; the emission intensity of the HTC sample was lower than that of Ti3C2T. x However, it still exhibits a relatively significant fluorescence response. In contrast, the PL strength of the BT-3 composite material is significantly reduced, falling below that of Ti3C2T across the entire testing wavelength range. x And HTC, indicating Ti3C2T x The heterojunction constructed with HTC effectively suppresses the recombination of photogenerated electron-hole pairs, promotes charge separation and transfer, and has a Schottky-characteristic electron transport structure, which improves the photoelectrocatalytic efficiency of the material.

[0092] X-ray photoelectron spectroscopy (XPS) was used to characterize the chemical valence states of Ti and F elements and the changes in interfacial electronic structure in the material using high-resolution X-ray photoelectron spectroscopy. The result is Figure 9 a of Ti 2p and Figure 9 b of F 1s High-resolution XPS spectra show that, compared with pure Ti3C2T xIn contrast, the characteristic peaks of Ti 2p in BT-3, including Ti-C, Ti-O, Ti-OH, and Ti-F, all shifted to varying degrees towards lower binding energies. Simultaneously, the characteristic peaks of Ti-OF, CF, and Ti-F in the F 1s spectrum also showed a low binding energy shift of approximately 0.1 eV. This indicates that Ti3C2T in the BT-3 composite material... x HTC acquired the electronic component, Ti3C2T. x There is a significant interfacial charge transfer effect. This interfacial electronic interaction facilitates the formation of Schottky contacts or built-in electric fields, thereby reducing the probability of carrier recombination.

[0093] The rotating ring-disk electrode (RRDE) method was used to test the disk current and ring current response of the sample during the oxygen reduction reaction, and the number of electrons transferred was calculated. The result is Figure 10 The RRDE test results show that BT-3 and Ti3C2T x Significant disk current and ring current responses were observed during the oxygen reduction reaction, indicating that the reaction was accompanied by H2O2 / HO2. - The formation of intermediate products. Based on RRDE data, the electron transfer number of BT-3 is calculated to be 2.95, lower than that of Ti3C2T. x The value of 3.20 indicates that the oxygen reduction process after BT-3 composite is transformed by Ti3C2T x The upper is closer to 4e - Path regulation is the epigenetic near 3e - The oxygen reduction process. This result indicates that HTC in BT-3 reacts with Ti3C2T. x The interfacial coupling effect alters the adsorption and transformation behavior of oxygen intermediates, making the ORR process more inclined to proceed via H2O2 / HO2. - The intermediate undergoes a non-complete four-electron reduction to generate H₂O / OH. - .

[0094] Depend on Figure 11 The test results and corresponding rate constants of the formation of ·OH and H2O2 show that different HTC / Ti3C2T x The mass ratio has a significant impact on the concentration of reactive oxygen species formed. With increasing HTC content, the ·OH formation capacity of the composite material first increases and then decreases. When HTC is mixed with Ti3C2T... x When the mass ratio increased from 2.5 to 3, the cumulative concentration of ·OH increased significantly, reaching a maximum of 118.9 μmol / L in BT-3; the corresponding ·OH formation rate constant also reached its maximum, at 1.13 μmol·L. -1 ·min -1 It is significantly higher than that of pure Ti3C2T.x HTC and other composite samples were also tested. Meanwhile, the cumulative H2O2 concentration of BT-3 was only 136.0 μmol / L, and the H2O2 formation rate constant was 1.99 μmol·L⁻¹. -1 ·min -1 The concentrations were at a low level. This indicates that the introduction of an appropriate amount of HTC significantly promoted the 3-electron ORR pathway by constructing a highly efficient Schottky heterojunction interface structure, resulting in the rapid conversion of generated H2O2 into ·OH and achieving efficient ·OH generation. However, when the HTC content continued to increase to BT-3.5 and BT-4, the ·OH generation capacity decreased significantly, with the cumulative ·OH concentration decreasing to 62.5 and 57.7 μmol / L, respectively, and the corresponding ·OH generation rate constants also decreasing to 0.61 and 0.39 μmol·L, respectively. -1 ·min -1 Meanwhile, the cumulative concentration of H2O2 increased significantly, reaching 244.9 and 458.3 μmol / L for BT-3.5 and BT-4, respectively, and their H2O2 formation rate constants also increased to 4.29 and 7.34 μmol·L, respectively. -1 ·min -1 This trend is gradually approaching that of pure HTC. This suggests that an excessive number of HTC devices will overshadow or disable the Ti3C2T. x The active sites on the surface weaken the effective electronic coupling and charge transfer efficiency at the interface between the two phases, making the reaction more likely to stop at the 2e-phase formation of H2O2. - The ORR pathway is not conducive to the further activation of H2O2 into ·OH, ultimately leading to a decrease in the ability to generate ·OH.

[0095] Depend on Figure 12 The pH effect experiment results show that the BT-3 catalyst exhibits excellent tetracycline degradation activity under different initial pH conditions. When the initial pH is 2, 4, 6, 8, 10, 12, 13, and unadjusted, the tetracycline degradation rates reach 93.1%, 100%, 98.6%, 99.3%, 98.4%, 97.9%, 80.2%, and 99.8%, respectively. Within a wide pH range of 2–12, the degradation rate is consistently above 93%, with only a slight decrease in activity under strongly alkaline conditions (pH=13). This indicates that the BT-3 catalyst has good adaptability to acidic, neutral, and weakly alkaline environments, possessing excellent wide pH applicability.

[0096] Depend on Figure 12It was found that the BT-DTAB and BT-CTAB-free catalysts achieved tetracycline degradation rates of 94.6% and 74.0%, respectively, within 60 min of the photoelectrocatalytic reaction. This indicates that the BT-DTAB catalyst prepared with dodecyltrimethylammonium bromide as an aid exhibits superior photoelectrocatalytic performance in tetracycline degradation. Therefore, the introduction of DTAB significantly improves the tetracycline degradation efficiency.

[0097] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A biomass hydrothermal char / Ti3C2T x A method for preparing heterostructured catalysts, characterized in that, include: Step 1: Disperse biomass raw material particles in an aqueous solution containing acid and cationic dispersant and carry out a hydrothermal reaction to obtain surface-modified biomass hydrothermal char. Step 2: Place Ti3C2T x The surface-modified biomass hydrothermal char obtained in step 1 was dispersed in a mixed solvent of alcohol and water to obtain a dispersion system. The pH of the dispersion system was adjusted to 4.1–6.7, and compounding was performed under intermittent pulsed ultrasonic conditions to allow the biomass hydrothermal char to insert into Ti3C2T. x Between layers, after drying, biomass hydrothermal char / Ti3C2T is obtained. x Heterogeneous catalysts.

2. The preparation method according to claim 1, characterized in that, The acid content in the aqueous solution described in step 1 is 0.5–3 mol / L; The concentration of the cationic dispersant is 0.001–0.05 g / mL; The ratio of the biomass feed pellets to the aqueous solution is 1 g: (8-20) mL; The biomass raw material is selected from at least one of corn cob, grapefruit peel, and rice husk; The acid is at least one selected from sulfuric acid, hydrochloric acid, nitric acid, acetic acid, phosphoric acid, formic acid, citric acid, and oxalic acid. The cationic dispersant is a quaternary ammonium salt cationic surfactant, selected from at least one of hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, dodecyltrimethylammonium bromide, octadecyltrimethylammonium chloride, dodecyltrimethylammonium chloride, tetradecyltrimethylammonium bromide, tetradecyltrimethylammonium chloride, and octadecyltrimethylammonium bromide.

3. The preparation method according to claim 1, characterized in that, The specific conditions for the hydrothermal reaction described in step 1 include: The temperature is 160–220 °C, and the reaction time is 12–48 h.

4. The preparation method according to claim 1, characterized in that, Step 2, which describes the composite process under intermittent pulsed ultrasound conditions, specifically includes: The ultrasonic amplitude is set to 20%–60%; The pulse working mode is: alternating cycles of 10-50 seconds of operation and 10-50 seconds of interval, with a total ultrasound time of 20 minutes to 2 hours.

5. The preparation method according to claim 1, characterized in that, In step 2, the surface-modified biomass hydrothermal carbon and Ti3C2T x The mass ratio of the materials is 0.5-6:1; The alcohol in the mixed solvent of alcohol and water is at least one of anhydrous ethanol, methanol, isopropanol, n-propanol, ethylene glycol, and glycerol; The volume ratio of alcohol to water is 20:1 to 1:1; The concentration of biomass hydrothermal char is 0.3–4.5 g / L.

6. The preparation method according to claim 5, characterized in that, In step 2, biomass hydrothermal char and Ti3C2T x The mass ratio of the materials is 2.8 to 3.2:

1.

7. The preparation method according to claim 1, characterized in that, The biomass hydrothermal char / Ti3C2T obtained in step 2 x The specific surface area of ​​the heterostructure catalyst is 12–45 m². 2 / g, with a pore size of 10–15 nm.

8. The biomass hydrothermal char / Ti3C2T prepared by the method according to any one of claims 1-7 x Heterogeneous catalysts.

9. A photoelectrocatalytic cathode, characterized in that, The catalyst prepared by the method according to any one of claims 1-7.

10. The biomass hydrothermal char / Ti3C2T prepared by the method described in any one of claims 1-7 x The application of at least one of the heterostructure catalysts and the photoelectrocatalytic cathode of claim 9 in the photoelectrocatalytic removal of antibiotics from wastewater.

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