CN110280313B

CN110280313B - Three-dimensional structure loaded TiO2-xMethod for producing a material

Info

Publication number: CN110280313B
Application number: CN201910624758.5A
Authority: CN
Inventors: 卢松涛; 吴晓宏; 李杨; 秦伟
Original assignee: Harbin Institute of Technology
Current assignee: HARBIN QINHAO TECHNOLOGY Co.,Ltd.; Harbin Institute of Technology
Priority date: 2019-07-11
Filing date: 2019-07-11
Publication date: 2020-03-24
Anticipated expiration: 2039-07-11
Also published as: CN110280313A

Abstract

Three-dimensional structure loaded TiO_2‑xA preparation method of a material belongs to the technical field of photocatalysis. The invention aims to solve the problem of TiO₂Low photocatalytic efficiency and difficult recovery of powder. The method comprises the following steps: preparation of CB/TiO_2‑xPowder; secondly, preparing a Polycarbonate (PC) cone by taking PC as a raw material; thirdly, the step one is CB/TiO_2‑xDissolving the powder in an organic solvent, and performing ultrasonic treatment to obtain CB/TiO_2‑xSuspending the suspension, pouring the suspension into a spray gun, uniformly spraying at least 3 layers on the PC cone, washing with deionized water, and vacuum drying. The invention improves TiO₂The solar water heater has the advantages that the solar water heater is endowed with solar energy to drive water evaporation performance while the photocatalytic performance is simultaneously endowed, and the solar water heater is used for producing clean water, so that not only can solar energy be utilized to the maximum extent, but also dual-function and high-efficiency water treatment can be realized.

Description

Three-dimensional structure loaded TiO2-xMethod for producing a material

Technical Field

The invention belongs to the technical field of photocatalysis; in particular to polycarbonate supported CB/TiO_2-xA method for preparing the material.

Background

The development of human society is seriously influenced by the global water resource shortage and pollution problems. At present, the technology for purifying sewage is various, and the water purifying method with a single principle cannot achieve the efficient purifying effect and consumes a large amount of financial resources and material resources. The solar energy is used for wastewater treatment, including photocatalytic degradation of organic pollutants and solar energy driving water evaporation, and is an effective way for solving the problem.

Photocatalytic degradation and solar-driven water evaporation are considered to be the most promising technologies to address the problem of shortage of clean water resources. Although many efforts are made to explore the efficient production of clean water, the prior art has many problems of high cost, single decontamination function, low efficiency and the like, thereby significantly limiting the popularization and application of the water. Therefore, the dual functions (photocatalysis and water evaporation) are integrated into the same composite material for producing clean water, so that not only can solar energy be utilized to the maximum extent, but also the dual-function high-efficiency water treatment can be realized.

TiO₂As a photocatalyst, the photocatalyst is environment-friendly, nontoxic, good in stability and high in active site, and therefore has attracted extensive attention in the field of photocatalysis. But due to TiO₂The forbidden band width is large, so that the optical response range is narrow, the quantum efficiency is low, the photocatalytic activity is seriously influenced, and the TiO has high activity₂The recovery problem of the powder catalyst greatly influences the catalytic effect and the practicability of the powder catalyst. Although the problem of recycling the photocatalyst can be avoided by curing it, the realization of effective immobilization still requires an investigation, and the photocatalytic performance still needs to be improved.

Disclosure of Invention

The invention aims to solve the problem of TiO₂The photocatalytic efficiency is low and the powder is difficult to recover; provides a three-dimensional structure loaded TiO_2-xA method for preparing the material.

The invention improves TiO₂The solar water heater has the advantages that the solar water heater is endowed with solar energy to drive water evaporation performance while the photocatalytic performance is simultaneously endowed, and the solar water heater is used for producing clean water, so that not only can solar energy be utilized to the maximum extent, but also dual-function and high-efficiency water treatment can be realized.

In order to solve the technical problem, the invention provides a three-dimensional structure supported TiO_2-xThe preparation method of the material comprises the following steps:

step one, Carbon Black (CB) was added to Tris buffer (pH 8.5, 50mM), sonicated for 30min, and stirred, followed by addition of TiO_2-xContinuously stirring, adding 2mg/mL dopamine hydrochloride after the mixed solution is uniform, uniformly stirring, then placing in a shaking table, introducing air while shaking, treating for 12h, washing with deionized water for several times, and drying in vacuum at 60 ℃ to obtain CB/TiO_2-xPowder;

step two, taking Polycarbonate (PC) as a raw material, 3D printing a hollow cone, sequentially performing stress removal and oil removal treatment, then washing the hollow cone with deionized water, then soaking the hollow cone in absolute ethyl alcohol for 10min, taking out the hollow cone, directly transferring the hollow cone into a Tris-HCl buffer solution with the concentration of 50mM, then adding dopamine hydrochloride (2mg/mL), and performing vacuum drying to obtain the PC cone;

step three, the step one is CB/TiO_2-xDissolving the powder in an organic solvent, performing ultrasonic treatment, and preparing CB/TiO with the concentration of 10-20 mg/mL_2-xPouring the suspension into a spray gun, uniformly spraying at least 3 layers on a PC cone, washing with deionized water, and vacuum drying at 30 deg.C for 4 hr to obtain three-dimensional structure loaded TiO_2-xA method for preparing the material.

Further defining, step one said TiO_2-xIs prepared by the following steps:

step 1: dissolving 0.6g of P25 in 60mL of NaOH solution with the concentration of 10mol/L, performing ultrasonic treatment for 30min, transferring the solution to a hydrothermal kettle, performing hydrothermal treatment for 12-48 h at 200 ℃, washing the solution with 0.1M hydrochloric acid until the pH value reaches 2.0 +/-0.2, washing the solution with deionized water for multiple times, washing the solution with absolute ethyl alcohol for multiple times, drying the solution for 12h at 60 ℃ under a vacuum condition, putting the dried solution into a tubular furnace, calcining the solution for 4h at 500 ℃, and naturally cooling the solution to room temperature to obtain white TiO₂A nanoribbon;

step 2: 0.2g of the white TiO obtained in step one is taken₂Adding 0.4g of sodium borohydride into the nanobelt, fully grinding and uniformly mixing the nanobelt, putting the nanobelt into a tube furnace, and putting the nanobelt into the tube furnace under argonIn the atmosphere, at 5 ℃ for min^-1Heating to 300-450 ℃, keeping the temperature for 3h, naturally cooling to room temperature, dissolving the mixture in deionized water, performing suction filtration, washing, and vacuum drying at 70 ℃ for 12h to obtain black TiO_2-xA nanoribbon.

Further limiting, the temperature of the solution is 5 ℃ min in the step 2^-1The temperature rise rate of (2) is increased to 360 ℃.

Further limiting, step one, CB and TiO_2-xThe mass ratio of (1): (1-5), the ratio of the mass of the CB to the volume of the Tris buffer solution is (0.05-0.5) g, (10-100) mL, and the ratio of the mass of the CB to the volume of the dopamine hydrochloride is (2-10) g:1 mL.

Further limiting, the specific steps of 3D printing the hollow cone in the second step are as follows:

putting a PC wire material into a vacuum drying treatment at 60 ℃ for 12h before printing, designing a target printing substrate structure by using 3D Max (3D Studio Max) software, identifying the file by using a 3D printer, then carrying out printing operation, setting the nozzle diameter of the printer to be 0.4mm, the nozzle temperature to be 260 ℃, the printer platform to be 90 ℃, the room temperature to be 80 ℃, sending 1.75mm monofilaments into an FDM printer through two pinch rollers without using any adhesive, keeping the layer printing speed to be 1.5m/min, and setting the layer height to be 0.05mm, and then carrying out layer-by-layer printing to obtain the hollow cone.

Further limiting, the vertex angle of the hollow cone in the step two is 60-120 degrees.

Further limiting, in step two, drying is carried out for 12h under vacuum at 45 ℃.

Further limiting, the organic solvent in the third step is absolute ethyl alcohol.

Further defined, the thickness of the coating on the PC cone after spraying in step three was 6 μm.

Further limiting, step three was dried under vacuum at 30 ℃ for 4 h.

The invention three-dimensional structure load TiO_2-xThe material can realize high-efficiency degradation (99.94%) of MG solution within 2min, and the catalytic activity of the material is not obviously changed after 20 cycles, so that the material is very stable as a photocatalytic material.

The invention three-dimensional structure load TiO_2-xMaterialDue to TiO_2-xNanostructure structure, presence of CB, and Ti³⁺And the introduction of oxygen vacancy, so that the photocatalyst has excellent photocatalytic performance.

The invention three-dimensional structure load TiO_2-xThe material has good solar energy driving water evaporation capacity, and due to the super-strong light absorption performance (99.68%), the water evaporation rate in 3 times of sunlight is 4.5371 kg/(m)²h) The photothermal conversion efficiency reaches 93.52%. With CB/TiO_2-xThe ion (Na) in the collected evaporation water is used for carrying out the seawater desalination experiment by PC⁺、Mg²⁺、K⁺、Ca²⁺) The concentration showed 4 orders of magnitude decrease (2.1mg/L) better than the drinking water standard specified by WHO.

Drawings

FIG. 1 is a schematic representation of TiO preparation in example 1_2-xA TEM photograph of; a)2 μmTEM pictures, b)200nmTEM pictures; c) a 50nmHRTEM photograph, d) a 5nmHRTEM photograph;

FIG. 2 is sample TiO₂(P25)、TiO₂、TiO_2-xUV-Vis-NIR absorption spectrum of (A);

FIG. 3 shows CB/TiO mixtures of different synthesis mass ratios_2-xSEM photograph of (a) CB and TiO_2-xThe mass ratio of (1): 1, b) CB with TiO_2-xThe mass ratio of (1): 2, c) CB with TiO_2-xThe mass ratio of (1): 3, d) CB with TiO_2-xThe mass ratio of (1): 4, e) CB with TiO_2-xThe mass ratio of (1): 5;

FIG. 4 is CB/TiO_2-xSEM photograph of (1) and corresponding mapping a) CB/TiO_2-xA drawing; b) ti; c) o; d) c;

FIG. 5 shows CB/TiO mixtures of different synthesis mass ratios_2-xUV-Vis-NIR absorption spectrum of (A);

FIG. 6 is CB/TiO_2-xA schematic diagram of a photocatalytic mechanism;

FIG. 7 is a physical diagram of a PC cone of different apex angles, a) apex angle 60 degrees, b) apex angle 90 degrees, c) apex angle 120 degrees;

FIG. 8 is a physical representation and SEM pictures of a PC 3D cone for different printing processes a), b), c) for

processes

1, 3 and 5; d) e), f) are SEM pictures of

processes

1, 3 and 5;

FIG. 9 example1 spray coated CB/TiO_2-xUV-Vis-NIR absorption spectrum of/PC;

FIG. 10 is the photocatalytic activity of different samples under light;

FIG. 11 shows different CB/TiO_2-xCB/TiO corresponding to spraying layer number_2-xThe catalytic performance of/PC;

FIG. 12 is a graph of water evaporation mass loss for different samples;

FIG. 13 shows Na before and after desalting⁺，Ca²⁺，K⁺And Mg²⁺Salinity of (a);

FIG. 14 is CB/TiO_2-xThe catalytic degradation stability of PC;

FIG. 15 is CB/TiO_2-xStability of water evaporation performance of PC;

FIG. 16 is CB/TiO_2-xThe mechanism of efficient water purification of PC is shown schematically.

Detailed Description

Example 1: raw material TiO in this example_2-xIs prepared by the following steps:

step 1: dissolving 0.6g of P25 in 60mL of NaOH solution with the concentration of 10mol/L, performing ultrasonic treatment for 30min, transferring the solution to a hydrothermal kettle, performing hydrothermal treatment for 36h at 200 ℃, washing the solution with 0.1M hydrochloric acid until the pH value reaches 2.0 +/-0.2, washing the solution with deionized water for multiple times, washing the solution with absolute ethyl alcohol for multiple times, drying the solution for 12h at the vacuum condition of 60 ℃, putting the dried solution into a tubular furnace, calcining the solution for 4h at 500 ℃, and naturally cooling the solution to room temperature to obtain white TiO₂The nanobelts grow uniformly and have a belt-shaped structure with the size of about 4 mu m;

step 2: 0.2g of the white TiO obtained in step one is taken₂Adding 0.4g of sodium borohydride into the nanobelt, fully grinding and uniformly mixing the nanobelt, putting the nanobelt into a tubular furnace, and placing the nanobelt into the tubular furnace at the temperature of 5 ℃ for min in an argon atmosphere^-1Heating to 350 deg.C, keeping the temperature for 3h, naturally cooling to room temperature, dissolving the mixture in deionized water, filtering, washing, and vacuum drying at 70 deg.C for 12h to obtain black TiO_2-xNanobelt having a belt-like shape and containing Ti³⁺And oxygen vacancy, the malachite green solution can be degraded within 40min (99.94 percent), the degradation rate conforms to a first-order kinetic equation, and the rate constant k is 0.05692min^-1Is about TiO ₂5 times of (NBs).

In this example, a three-dimensional structure supported TiO_2-xThe preparation method of the material comprises the following steps:

step one, adding Carbon Black (CB) to Tris buffer (pH 8.5, 50mM), sonicating for 30min and stirring, followed by addition of TiO prepared as described above_2-xContinuously stirring, adding 2mg/mL dopamine hydrochloride after the mixed solution is uniform, uniformly stirring, then placing in a shaking table, introducing air while shaking, treating for 12h, washing with deionized water for several times, and drying in vacuum at 60 ℃ to obtain CB/TiO_2-xPowder;

in the first step, the ratio of the mass of the CB to the volume of the Tris buffer solution is 0.1g to 50mL, and the ratio of the mass of the CB to the volume of the dopamine hydrochloride is 5g to 1 mL.

The degradation of the MG solution can be realized within 3min by 99.95 percent. After five times of circulation, the catalytic activity is still kept above 89%, and the catalyst performance is relatively stable

Step two, taking Polycarbonate (PC) as a raw material, 3D printing a hollow cone, sequentially performing stress removal and oil removal treatment, then washing the cone clean by deionized water, then soaking the cone in absolute ethyl alcohol for treatment for 10min, taking out the cone, directly transferring the cone to a Tris-HCl buffer solution with the concentration of 50mM, then adding dopamine hydrochloride (2mg/mL), and performing vacuum drying for 12h at the temperature of 45 ℃ to obtain the PC cone;

step three, the step one is CB/TiO_2-xDissolving the powder in absolute ethyl alcohol, performing ultrasonic treatment, and preparing CB/TiO with the concentration of 15mg/mL_2-xPouring the suspension into a spray gun, uniformly spraying 3 layers on a PC cone, washing with deionized water, and vacuum drying at 30 deg.C for 4 hr to obtain three-dimensional structure loaded TiO_2-xMethod for preparing materials (labeled as CB/TiO)_2-x/PC)；

The specific steps of 3D printing the hollow cone in the second step are as follows:

putting a PC wire material into a vacuum drying treatment at 60 ℃ for 12h before printing, designing a target printing substrate structure by using 3D Max (3D Studio Max) software, identifying the file by a 3D printer, then carrying out printing operation, wherein the diameter of a nozzle of the printer is 0.4mm, the temperature of the nozzle is set to be 260 ℃, the temperature of a printer platform is set to be 90 ℃, the room temperature is 80 ℃, no adhesive is used, feeding 1.75mm monofilaments into an FDM printer through two pinch rollers, keeping the layer printing speed at 1.5m/min, and setting the layer height to be 0.05mm, and then carrying out layer-by-layer printing to obtain a hollow cone with the apex angle of 60 degrees.

CB/TiO obtained in this example_2-xthe/PC can realize the high-efficiency degradation (99.94%) of the MG solution within 2min, and the catalytic activity of the MG solution is not obviously changed after 20 times of circulation, so that the MG solution is very stable as a photocatalytic material.

CB/TiO obtained in this example_2-xThe PC has good solar-driven water evaporation capacity, and due to the super-strong light absorption performance (99.68%), the water evaporation rate in 3 times of sunlight is 4.5371 kg/(m)²h) The photothermal conversion efficiency reaches 93.52%. With CB/TiO_2-xThe ion (Na) in the collected evaporation water is used for carrying out the seawater desalination experiment by PC⁺、Mg²⁺、K⁺、Ca²⁺) The concentration showed 4 orders of magnitude decrease (2.1mg/L) better than the drinking water standard specified by WHO.

The procedure of this example gives TiO_2-xThe TEM photograph of (A) is shown in FIG. 1. It can be seen that the sample exhibited a banded structure in TiO_2-xWas observed in the high magnification image, and it was found that TiO could be observed in the high magnification image₂And an amorphous shell, the 0.35nm lattice fringes found to correspond to TiO₂(100) A crystal plane of (a). TiO 2_2-xThe amorphous shell of (a) helps to promote electron transfer and separation, thereby promoting the photocatalytic performance of the catalyst.

The procedure of this example gives TiO_2-xThe UV-Vis-NIR absorption spectrum of (A) is shown in FIG. 2. TiO 2_2-xAt 400nm-2500nm compared with TiO₂And TiO₂All have strong absorption, and the response to light is widened to the whole solar spectrum range, which shows that the TiO modified by autodoping_2-xThe light absorption properties are greatly changed, and the strong absorption is attributable to the presence of Ti³⁺By autodoping of TiO_2-xThe forbidden bandwidth of the band is reduced.

CB/TiO of different synthetic mass ratios_2-xThe SEM photograph is shown in FIG. 3, and the CB and TiO are all realized under the action of PDA_2-xBut the load situation is different due to the difference of the ratio of the initially added CB. As shown in FIG. 3a, the agglomeration of CB occurred on a larger scale, mainly due to the large amount of CB initially charged, and also due to the action of PDA, the agglomeration of CB occurred to a larger extent. The agglomeration was attenuated to varying degrees with decreasing amounts of CB added, fig. 3b is 1: SEM image at 2 shows that CB is successfully loaded on TiO_2-xAnd relatively uniformly supported, is advantageous for its photocatalytic degradation performance, as can be confirmed in subsequent performance tests. FIG. c shows CB and TiO_2-xThe load proportion is 1: in the SEM image at time 3, a significant reduction in the amount of CB was observed and the agglomeration was significantly improved. FIGS. 3d, e correspond to SEM images at a loading mass ratio of 1:4 and 1:5, respectively, at which the amount of CB had been substantially reduced, but successful loading of CB on TiO could still be observed_2-xAnd still relatively uniform. From the morphology change of fig. 3a, b, c, d, e, it can be seen that the loading effect is different with the initial CB amount, but the black color is seen from the appearance, and the light absorption performance is different.

CB/TiO obtained in step one of this example_2-xThe SEM photograph of (a) and the corresponding mapping are shown in fig. 4. CB/TiO is clearly seen_2-xIs composed of three elements of Ti, O and C, and the distribution of the elements of Ti and O can be seen as well as TiO in the corresponding SEM picture_2-xThe shapes are consistent, and the C element is uniformly distributed in the TiO_2-xIn the area where the test showed successful CB and TiO_2-xThe load is carried out to successfully prepare the CB/TiO_2-x。

CB/TiO obtained in step three of this example_2-xThe UV-Vis-NIR absorption spectrum of (A) is shown in FIG. 5. It can be observed that the absorption of CB at 400nm-2500nm is stronger when CB is mixed with TiO_2-xAfter successful recombination, they interact with each other, the light absorption properties of both are improved, and the successfully loaded CB/TiO_2-xThe light absorption properties are improved compared to both before loadingHigh and well balanced in the light absorption properties of the whole spectrum from 250nm to 2500 nm. And it was found that the light absorption property was gradually increased as the content of CB was increased, but it was not found that the higher the content of CB was, the stronger the light absorption property was.

CB/TiO obtained in step three of this example_2-xThe photocatalytic mechanism of (2) is shown in FIG. 6, with Ti³⁺And introduction of oxygen vacancies in CB/TiO_2-xForms new impurity levels below the conduction band which will cause the CB/TiO to react_2-xThe band gap of (a) is narrowed, thereby enhancing the optical response to sunlight. On the other hand, Carbon Black (CB) is also an important factor that should not be overlooked for improving photocatalytic efficiency, because it plays a crucial role in enhancing adsorption capacity, electron transfer and separation of photo-generated electron-hole pairs. When the catalyst is exposed to light, in TiO_2-xWill generate a large number of photo-generated electrons in the Valence Band (VB) and immediately transfer to TiO_2-xOf Ti³⁺Defects and oxygen vacancies, leaving holes in VB. TiO 2_2-xIs excited to Ti³⁺E in defects and oxygen vacancies^-Will be rapidly transferred to CB and eventually with OH in solution^-And H₂The O reaction generates OH free radicals. At the same time, OH^-And H₂O is TiO_2-xThe holes in VB in the (A) are trapped to generate OH radicals. Finally, organic contaminants react with free radicals such as OH, O₂ ^-The reaction produces small molecular substances harmless to the environment. The rapid circulating system of the photo-generated electron-hole pairs accelerates the transfer of electrons and reduces the recombination rate of the electrons and the holes. During the catalytic reaction, oxygen vacancies may provide dangling bonds for adsorption of reaction substrates; due to the characteristic of local electron enrichment, the oxygen vacancy can also activate the inert chemical bond of the adsorption substrate and regulate the electronic structure of the adsorption substrate, so that the photocatalytic process is greatly influenced. Furthermore, TiO_2-xThe shape of the nano-belt is also beneficial to improving the photocatalytic activity, because the nano-belt has larger specific surface area, can increase surface active sites, is beneficial to the adsorption of pollutants and improves the lighting efficiency to the maximum extent. Thus, TiO_2-xNanostructure structure, presence of CB, Ti³⁺Synergistic with the introduction of oxygen vacanciesTo improve CB/TiO_2-xThe photocatalytic performance of (a).

A physical representation of the PC cones at different apex angles is shown in FIG. 7.

The printing process parameters of the PC 3D cone in step four of this example are shown in table 1. A physical picture and SEM picture of the PC 3D cone under different printing processes are shown in FIG. 8. In the figure 8, a, b and c are respectively prepared under three process conditions of a process 1, a process 3 and a process 5, the figure c can be seen to be smoother and more compact in appearance through comparison, the surface of the figure c is not subjected to hollow phenomenon caused by untimely cooling, in order to more clearly and accurately see the microstructure of the figure c, the microstructure of a printed microstructure sample under the condition of the embodiment can be found to be more textured and clearer in order to be more clearly seen through corresponding SEM pictures, the printed material surface is relatively flat and smooth, the layering is stronger, and the characteristics of the FDM printing technology are met.

TABLE 1 printing Process parameters for PC 3D Cone

In the third step of this example, the optimum spray-coated CB/TiO is obtained_2-xThe UV-Vis-NIR absorption spectrum of/PC is shown in FIG. 9. Through a series of screening of spraying parameters, the optimal spraying parameters are determined, and CB/TiO with the concentration of 15mg/mL is adopted_2-xThe ethanol dispersion liquid is used for spraying a PC three-dimensional structure, and the number of spraying layers is 3. The light absorption properties after spraying are shown in FIG. 9, which shows the change of the light absorption properties of the PC cone before and after spraying, the average light absorption rate of the PC three-dimensional structure before spraying in the range of 250nm to 2500nm reaches about 97%, and CB/TiO is loaded_2-xCB/TiO of three-dimensional structure of PC_2-xThe light absorption rate of the/PC composite catalyst in the full wave band of the solar spectrum reaches 99.67%, and the catalyst has excellent light absorption performance.

CB/TiO obtained in step five of this example_2-xFIG. 10 shows the photocatalytic performance analysis of PC, and FIG. 10(a) shows that the blank PC has a certain adsorption capacity for contaminants due to the hydrophilic treatment with PDA, but CB is subjected to the adsorption capacity for contaminantsAfter being loaded, the catalytic performance of the material is not obviously improved, which is mainly because CB does not have photocatalytic degradation capability, but CB/TiO₂、CB/TiO₂After the/PC three-dimensional structure is loaded, the catalytic degradation capability of the/PC three-dimensional structure is improved, mainly because the light absorption performance of the/PC three-dimensional structure is enhanced after the/PC three-dimensional structure is loaded. In contrast, CB/TiO_2-xAfter the/PC three-dimensional structure is reloaded, CB/TiO is found_2-xThe catalytic degradation capability of the/PC is compared with that of the CB/TiO_2-xImproved, 99.94% MG can be degraded at 2min, mainly because the degradation of MG contaminants is temperature dependent, while CB/TiO in the catalytic process is tested_2-xThe temperature of PC can reach about 72 ℃. Therefore, the catalytic degradation of MG is not improved well. FIG. 10(b) shows the percentage of MG degradation in 2min for different catalyst samples, from which the degradation degree of each catalyst in 2min can be clearly compared, when only CB/TiO is present_2-xthe/PC achieves 99.94%. FIG. 10(c) is a graph showing the degradation kinetics of MG organic contaminant for each catalyst, which shows that the degradation process conforms to the first order kinetics equation, and that CB/TiO_2-xThe apparent rate constant k of/PC is much larger than that of TiO₂/PC。

Different CB/TiO_2-xCB/TiO corresponding to spraying layer number_2-xthe/PC catalytic performance is shown in FIG. 11, and the change of the degradation curve corresponding to different samples in FIG. 11 shows that the CB/TiO is_2-xThe ability of PC to catalyze the degradation of MG solution when spraying CB/TiO_2-xCB/TiO when the number of layers is changed within a certain range_2-xThe degradation performance of PC to MG solution is gradually enhanced with the increase of the spraying layer number, but when the spraying layer number exceeds the range, CB/TiO_2-xThe degradation properties of PC to MG solution will not change any more. This is mainly because when the amount of catalyst is increased within a certain range, more active sites can be provided for the reaction; at the same time, more electron-hole pairs are generated per unit time; therefore, a greater number of organic molecules can participate in the reaction at the same time, which undoubtedly increases the efficiency of the photocatalytic degradation reaction. However, when the amount of the catalyst is increased to a certain extent, the amount of the catalyst is increased, and the photocatalytic activity is not changedThis is mainly because, when the adsorption saturation occurs after the catalyst is sprayed on the substrate, the amount of the catalyst is increased after the adsorption saturation is reached, and there is no significant promotion effect on the proceeding rate of the catalytic reaction. When CB/TiO_2-xIn the course of changing the number of sprayed layers from 1 to 5, it was found that when the number of sprayed layers of the catalyst was 3, the MG solution having a concentration of 10MG/mL could be degraded by 99.94% within 2min under the irradiation of Xe lamp light source. When the number of sprayed layers is more than 3, the CB/TiO_2-xThe degradation performance of PC to MG solution is not obviously changed; when the number of sprayed layers is changed from 1 to 3, the change of the sprayed layers on the degradation performance of MG can be obviously observed; when the number of spraying layers is 1 and 2, 99.92 percent and 99.93 percent of MG can be degraded in 15min and 10min respectively.

CB/TiO obtained in step five of this example_2-xThe water evaporation performance analysis of PC is shown in FIG. 12, which is a curve of water evaporation per unit area of different samples with Xe lamp light source under simulated sunlight irradiation. The application tests that the evaporation rate of the MG solution in the dark environment is 0.07037 kg/(m)²H) the water evaporation rate of the MG solution without any catalyst sample under xenon lamp irradiation was 1.05 kg/(m)²H) only CB/TiO_2-xThe water evaporation rate of the MG solution of the catalyst was 1.61 kg/(m)²H) and the rate of water evaporation when PC cones are present is compared to TiO_2-xThe catalyst is obviously improved, and the water evaporation rate is 2.29 kg/(m)²H). More remarkably, when CB/TiO_2-xAfter being loaded with a PC cone, the water evaporation rate can reach 4.53 kg/(m)²H) are greatly improved, mainly due to the CB/TiO_2-xThe light absorption performance of the composite material is improved after the composite material is compounded with PC, so that the photo-thermal conversion efficiency is enhanced. Under the irradiation of a xenon lamp light source (about 3 times of sunlight), CB/TiO_2-xThe photothermal conversion efficiency of/PC was calculated to be 93.52% according to the formula. The invention also uses CB/TiO_2-xthe/PC was tested in relation to salt treatment, in contrast to which the salt water before treatment and the collected condensate water were checked for the concentration of the relevant ions. Demonstrate CB/TiO_2-xthe/PC has excellent water evaporation and purification performance of solar driving water, as shown in figure 13. Using a solution having four kindsThe major ion (Na)⁺，K⁺，Ca²⁺And Mg²⁺) Desalting the brine. As can be seen from the figure, after desalination, all ions showed 4 orders of magnitude decreasing ion concentrations, all decreasing below 2.1mg/L, well below the ion content standards in drinking water as specified by the world health organization, and also below the ion content standards in drinking water of the United states environmental protection agency. Indicating CB/TiO_2-xthe/PC has excellent solar water purification effect.

The good stability of the catalyst is an important standard for testing the excellent performance of the catalyst, because the good circulation stability is a necessary condition for the catalyst to keep high-efficiency catalytic performance and economic benefit for a long time. The invention is to CB/TiO_2-xThe photocatalytic stability of the MG solution degraded by PC was tested, and as shown in FIG. 14, the degradation capability of the MG solution to the pollutant remained almost unchanged after the MG solution was continuously degraded by catalysis for 20 cycles, and the degradation percentage was only slightly changed, which indicates that the CB/TiO solution is changed in small amplitude_2-xthe/PC composite material has better catalytic stability, and proves that the CB/TiO realized by adopting the method of spraying on the treated PC three-dimensional structure_2-xThe load on the PC cone has firmer binding force, provides an improvement method for the problem of difficult recovery of the existing powder catalyst in application, and further proves that the CB/TiO_2-xThe possibility of the/PC composite material in practical popularization and application. The invention also relates to CB/TiO_2-xThe water evaporation performance of the PC was tested for cycle stability, and as shown in FIG. 15, it was found that CB/TiO_2-xAfter 20 water evaporation performance tests, the water evaporation rate of the/PC has slight fluctuation and remains stable as a whole, which indicates that the CB/TiO_2-xthe/PC has good stability in the aspect of photo-thermal conversion performance.

CB/TiO_2-xThe high-efficiency water purification mechanism of/PC is shown in figure 16, and CB/TiO_2-xPhotocatalyst is formed by TiO_2-xNanostructure structure, presence of CB, and Ti³⁺And the introduction of oxygen vacancy, so that the photocatalyst has excellent photocatalytic performance. When mixing CB/TiO_2-xSpraying on the hydrophilic modified PC cone of PDAAfter surface, the obtained CB/TiO_2-xthe/PC composite material shows excellent light absorption in the whole solar spectrum range. In a solar driven water evaporation process, sufficient water supply and low heat loss are provided, and in a photocatalytic process, excellent full spectrum absorption is provided for the catalyst. Thus, this result fully demonstrates CB/TiO_2-xthe/PC composite material not only has remarkable solar-driven water evaporation performance, but also has excellent photocatalytic performance. CB/TiO_2-xThe application of the high-efficiency and double-function water purification performance of the/PC composite material breaks through the limitation of single application of the traditional water purification material, and provides a new strategy for developing the high-efficiency and practical water purification material.

Claims

1. Three-dimensional structure loaded TiO_2-xThe preparation method of the material is characterized by comprising the following steps:

step one, carbon black is added into Tris-HCl buffer solution with pH =8.5 and 50mM, ultrasonic treatment is carried out for 30min, stirring is carried out on the mixture, and then TiO is added_x2-Continuously stirring, adding 2mg/mL dopamine hydrochloride after the mixed solution is uniform, uniformly stirring, then placing in a shaking table, introducing air while shaking, treating for 12h, washing with deionized water for several times, and vacuum drying at 60 ℃ to obtain carbon black/TiO_x2-Powder;

step two, using polycarbonate as a raw material, 3D printing a hollow cone, sequentially performing stress removal and oil removal treatment, then washing the hollow cone with deionized water, then soaking the hollow cone in absolute ethyl alcohol for 10min, taking out the hollow cone, directly transferring the hollow cone into a Tris-HCl buffer solution with the concentration of 50mM, then adding 2mg/mL dopamine hydrochloride, and performing vacuum drying to obtain the polycarbonate cone;

step three, mixing the carbon black/TiO in the step one_x2-Dissolving the powder in an organic solvent, performing ultrasonic treatment, and preparing carbon black/TiO with the concentration of 10-20 mg/mL_2-xPouring the suspension into a spray gun, uniformly spraying at least 3 layers on the polycarbonate cone, washing with deionized water, and vacuum drying to obtain the three-dimensional structure loaded TiO_2-xA material;

wherein, the TiO in the step one_x2-Is prepared by the following steps:

step 2: 0.2g of the white TiO obtained in step 1 was taken₂Adding 0.4g of sodium borohydride into the nanobelt, fully grinding and uniformly mixing the nanobelt, putting the nanobelt into a tubular furnace, and placing the nanobelt into the tubular furnace at the temperature of 5 ℃ for min in an argon atmosphere^-1Heating to 300-450 ℃, keeping the temperature for 3h, naturally cooling to room temperature, dissolving the mixture in deionized water, performing suction filtration, washing, and vacuum drying at 70 ℃ for 12h to obtain black TiO_2-xA nanoribbon;

carbon black and TiO in the first step_x2-The mass ratio of (1): (1-5), the ratio of the mass of the carbon black to the volume of the Tris-HCl buffer solution is (0.05-0.5) g, (10-100) mL, and the ratio of the mass of the carbon black to the volume of the dopamine hydrochloride is (2-10) g:1 mL.

2. The three-dimensional structure supported TiO of claim 1_2-xThe preparation method of the material is characterized in that the temperature is 5 ℃ min in the step 2^-1The temperature rise rate of (2) is increased to 360 ℃.

3. The three-dimensional structure supported TiO of claim 1_2-xThe preparation method of the material is characterized in that the specific steps of 3D printing the hollow cone in the step two are as follows: before printing, putting polycarbonate wires into a vacuum drying treatment at 60 ℃ for 12h, designing a target printing substrate structure by using 3D Max software, and printing after identifying the file by using a 3D printer, wherein the diameter of a nozzle of the printer is 0.4mm, the temperature of the nozzle is set to be 250-260 ℃, the temperature of a printer platform is set to be 90 ℃, the room temperature is 80 ℃, and no any other material is usedAnd (3) feeding 1.75mm monofilaments into an FDM printer through two pinch rollers, keeping the layer printing speed at 1.5m/min and setting the layer height to be 0.05mm, and then printing layer by layer to obtain the hollow cone.

4. The three-dimensional structure supported TiO of claim 3_2-xThe preparation method of the material is characterized in that the spraying temperature is 260 ℃.

5. The three-dimensional structure supported TiO of claim 1_2-xThe preparation method of the material is characterized in that the vertex angle of the hollow cone in the step two is 60-120 degrees.

6. The three-dimensional structure supported TiO of claim 1_2-xThe preparation method of the material is characterized in that in the second step, the material is dried for 12 hours in vacuum at the temperature of 45 ℃.

7. The three-dimensional structure supported TiO of claim 1_2-xThe preparation method of the material is characterized in that the organic solvent in the step three is absolute ethyl alcohol, and the material is dried for 4 hours in vacuum at the temperature of 30 ℃.

8. The three-dimensional structure supported TiO of claim 1_2-xThe preparation method of the material is characterized in that 3 layers are sprayed on the polycarbonate cone in the third step.