A Cs 0.32 WO3 / Cu x S nano-heterojunction photothermal conversion material and preparation method thereof

Abstract

The present invention belongs to the field of photothermal conversion materials, and specifically relates to a Cs 0.32 WO3 / Cu x S nano heterojunction photothermal conversion material and its preparation method. The present invention first uses a hydrothermal method to prepare Cs 0.32 WO3 / CuS composite precursor material, then, in a nitrogen atmosphere, the precursor was treated by high temperature calcination at different temperatures and times to obtain Cs 0.32 WO3 / Cu x S nano heterojunction photothermal conversion material. In the present invention, Cs with different dimensions 0.32 WO3 and Cu x S particles form a heterojunction structure. This material can absorb sunlight and generate a large amount of heat energy through the non-radiative relaxation effect of the heterojunction. It is a nanomaterial with a fast heating rate and high photothermal conversion efficiency, and has shown good application prospects in the field of solar desalination.

Description

Technical Field

[0001] The present invention belongs to the technical field of photothermal conversion materials, and specifically relates to a Cs 0.32 WO3 / Cu x S nanoheterojunction photothermal conversion material and a preparation method thereof. Background Art

[0002] Photothermal steam conversion is a new technology that uses green and clean solar energy to evaporate seawater, thereby alleviating the shortage of fresh water resources. However, the practical large-scale application of this technology is severely restricted due to reasons such as the extremely low energy conversion efficiency and insufficient heat output of photothermal conversion materials. Therefore, the development of high-performance photothermal conversion materials is the key to promoting solar seawater desalination technology.

[0003] In the solar spectrum received on the earth's surface, the energy proportion of visible light and near-infrared light regions exceeds 95%, among which the thermal effect of near-infrared light is particularly significant. In the studies so far, semiconductor materials such as cesium tungsten bronze (Cs 0.32 WO3) and copper sulfide (CuS) have received extensive attention due to their rich morphology dimensions, strong photothermal conversion ability and environmental friendliness. Previously, some scholars prepared sheet-like CuS [Z.Zheng, et al, Small, 2021, 17, 2103461]. This two-dimensional sheet-like structure can provide a larger transmission area for carrier transmission; at the same time, CuS has a relatively narrow bandgap and excellent light absorption in the full spectrum. However, serious electron and hole recombination problems will occur during the excitation process of single CuS, affecting the carrier lifetime and further affecting the heat generation effect. Therefore, compounding a semiconductor material with enhanced near-infrared light absorption is crucial for improving the carrier lifetime and the thermal conversion efficiency of solar energy.

[0004] Tungsten bronze (M x WO3, M = Cs, K, Na, NH 4+ etc., 0 <x <1) is a non-stoichiometric compound with a bronze-like luster and also a narrow-bandgap semiconductor material. This substance has strong near-infrared light absorption, mainly relying on the free electrons aggregated in the conduction band to induce local surface plasmon resonance effect, thereby absorbing (shielding) near-infrared light. Research shows [X.Wu, et al, Nanoscale, 2015, 7, 17048-17054] that compared with existing nano near-infrared absorption materials such as antimony-doped tin oxide, indium tin oxide and lanthanum hexaboride, nano cesium tungsten bronze (Cs x WO3) has the strongest near-infrared absorption performance, and this substance can quickly rise to a high temperature after absorbing light, indicating that it has a strong photothermal conversion effect. Therefore, Cs xWO3 has shown promise in infrared photothermal therapy. However, due to its low absorption in the visible light region, it has not yet been widely used in solar desalination, which requires full-spectrum photothermal conversion.

[0005] In summary, combined with Cs x The super-strong near-infrared photothermal conversion efficiency of WO3 and the narrow semiconductor band gap and full-spectrum photothermal conversion performance of CuS materials complement each other to prepare efficient photothermal conversion materials with important practical application value. Summary of the Invention

[0006] The purpose of the present invention is to make up for the shortcomings of the existing field of photothermal conversion materials and propose a Cs 0.32 WO3 / Cu x S nano heterojunction photothermal conversion material and its preparation method, the material can fully absorb the solar energy radiated to the earth's surface and quickly convert it to release a large amount of heat energy.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A Cs 0.32 WO3 / Cu x S nano heterojunction photothermal conversion material, composed of cesium tungsten bronze (Cs 0.32 WO3) nanoparticles and copper sulfide (Cu x S) forms a heterojunction structure.

[0009] The present invention also provides a Cs 0.32 WO3 / Cu x The preparation method of S nano heterojunction photothermal conversion material is firstly prepared by hydrothermal method. 0.32 WO3 / CuS precursor, Cs 0.32 WO3 / CuS precursor was calcined in nitrogen atmosphere to prepare Cs 0.32 WO3 / Cu x S nano-photothermal conversion material.

[0010] Preferably, the Cs 0.32 The calcination temperature of the WO3 / CuS precursor is 300-500°C, and the calcination time is 60-400 minutes. If the calcination temperature is too high or the calcination time is too long, it will lead to excessive CuS defects and serious CuS agglomeration, which is not conducive to light absorption. If the calcination temperature is too low or the calcination time is too short, it will lead to too few CuS defects, reducing the carrier migration path at the heterojunction interface, weakening the non-radiative relaxation effect, and low thermal conversion efficiency.

[0011] Preferably, the hydrothermal method is used to prepare Cs 0.32 The steps of WO3 / CuS precursor are as follows:

[0012] S1, Cs 0.32 WO3 and Cu(NO3)2 particles were added to ionized water in a mass ratio of 0.6:1 to 2.4:1 and prepared into Cs 0.32 WO3 and Cu(NO3)2 mixed solution, Na2S is dispersed in deionized water to prepare Na2S solution;

[0013] S2. After the treatment in step S1 is completed, Cs 0.32 The mixed solution of WO3 and Cu(NO3)2 was added to the Na2S solution and mixed evenly by magnetic stirring, and then ultrasonic dispersion was performed to obtain Cu(NO3)2, Cs 0.32 Mixed solution of WO3 and Na2S;

[0014] S3, after the treatment of step S2 is completed, Cu(NO3)2, Cs 0.32 The mixed solution of WO3 and Na2S is placed in a reactor for hydrothermal treatment;

[0015] S4. After step S3, the product is taken out, filtered, and then vacuum dried to obtain Cs 0.32 WO3 / CuS precursor powder.

[0016] Preferably, in step S1, the Cs 0.32 The concentration of Cu(NO3)2 solution in the mixed solution of WO3 and Cu(NO3)2 is 0.1~0.4g / mL, and Cs 0.32 3-12g of WO3 powder and a Na2S solution concentration of 0.1-0.4g / mL. The concentration of the solution affects the growth and size of the resulting CuS crystals, thereby affecting the formation of the structure. If the concentrations of the two solutions are too low, most of the CuS crystals grow slowly and are too small, the carrier transmission path is blocked, and the transmission of photogenerated carriers and relaxation heat release are reduced. If the concentrations of the two solutions are too high, the CuS crystals grow too fast, the nanosheets stack severely, and the carrier transmission path is extended, which is not conducive to the transmission of photogenerated carriers and relaxation heat release.

[0017] Preferably, in step S2, the magnetic stirring time is 30 to 90 minutes, and the ultrasonic dispersion treatment time is 120 to 180 minutes. If the ultrasonic time is too short, segregation precipitation is likely to form, which is not conducive to crystal growth and the formation of a uniform heterojunction structure; if the ultrasonic time is too long, it will affect the growth size of the crystal, and the final formed CuS and Cs 0.32 The carrier transmission path of WO3 nano-photothermal conversion material is blocked, and the transmission and relaxation heat release of photogenerated carriers are reduced.

[0018] Preferably, in step S3, the hydrothermal reduction reaction temperature is 120-180°C and the reaction time is 10-20h. The reaction temperature and time will affect the crystal growth and structure of CuS, and further affect the formation of heterojunction with cesium tungsten bronze nanoparticles. If the reaction temperature is too low or the time is too short, the CuS crystals grow slowly and are too small in size. 0.32 The heterojunction interface area of ​​WO3 nano-photothermal conversion material becomes smaller, the carrier transmission path is blocked, and the transmission and relaxation heat release of photogenerated carriers are reduced; if the reaction temperature is too high or the time is too long, the CuS crystal grows rapidly and becomes too large, and high temperature easily forms by-products, resulting in the reaction between CuS and Cs 0.32 The light absorption of WO3 nano-photothermal conversion materials is weakened and the carrier transfer rate decreases.

[0019] Preferably, in step S4, suction filtration is used, the pore size of the filter paper is 30-100 μm, the vacuum drying temperature is 40-80°C, and the time is 24-72 hours. The pore size of the filter paper will affect the Cs 0.32 The purity and yield of WO3 / CuS. If the pore size of the filter paper is too small, Cs 0.32 The impurities in WO3 / CuS are not washed thoroughly, resulting in residual impurities, which will affect the carrier transport and photothermal performance. 0.32 WO3 / CuS easily penetrates the filter paper, resulting in Cs 0.32 The yield of WO3 / CuS is low.

[0020] Preferably, Cs 0.32 The WO3 / CuS precursor is calcined in a nitrogen atmosphere, washed and dried with a CS2 solution, and the drying temperature is 60-120°C.

[0021] The present invention first prepares Cs by hydrothermal method 0.32 WO3 / CuS precursor, and then the composite precursor is treated by high temperature calcination to prepare Cs 0.32 WO3 / Cu x S nano-photothermal conversion material, and finally the composite heterojunction material is washed with CS2 to wash away the precipitated sulfur, and then dried to obtain Cs 0.32 WO3 / Cu x S nanometer light-heat conversion material. The present invention utilizes Cs 0.32 WO3 / Cu x The mixed dimensional structure and appropriate defects of S nano-photothermal conversion materials shorten the migration path of photogenerated carriers, enhance the non-relaxation effect of carriers formed by defects, increase heat release, and thus improve the photothermal conversion efficiency and heat output. 0.32After calcination, the morphology of WO3 / CuS changes to form a one-dimensional and three-dimensional structure, which shortens the carrier conduction path, accelerates the carrier conduction rate, and ensures efficient light-heat conversion. 0.32 WO3 and Cu x The incorporation of S significantly enhances the photothermal conversion effect in the near-infrared region, enabling faster heating under natural light intensity. The material's short photothermal conversion response time and simple process make it a promising candidate for applications in solar desalination and other related photothermal-catalytic water purification applications.

[0022] Cs was prepared under hydrothermal conditions. 0.32 WO3 / CuS precursor, Cs was prepared by high temperature calcination 0.32 WO3 / Cu x S nano-photothermal conversion materials, by changing the calcination temperature and time, effectively control the CuS defects and the size of CuS particles; using Cs 0.32 The newly formed heterojunction interface of WO3 / CuS reduces the recombination of carriers and holes, prolongs the lifetime of carriers, increases the number of photogenerated carriers, and further enhances the non-relaxation heat release of photogenerated carriers, thereby improving the photothermal conversion performance.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1) Synthesis of Cs by hydrothermal method 0.32 In the process of WO3 / CuS precursor, the molar ratio can be changed to effectively control the microstructure of the precursor, thereby preparing Cs with high photothermal conversion performance. 0.32 WO3 / CuS precursor. The entire process is simple to operate, environmentally friendly and low-cost.

[0025] 2) Using high temperature calcination technology to control Cs 0.32 The calcination temperature of WO3 / CuS precursor material, thus forming Cs with defects 0.32 WO3 / Cu x S nano-photothermal conversion material. As the temperature rises, the defects of CuS gradually increase, and Cs 0.32 WO3 and Cu x The morphology of S gradually changes, and the best morphology of Cs 0.32 WO3 / Cu x The S heterojunction can increase the migration speed and migration path of photogenerated carriers, improve the output of non-relaxation heat release, thereby generating a local thermal effect and improving the solar thermal conversion efficiency.

[0026] 3) Cs 0.32 WO3 / Cu xS nano-heterojunction photothermal conversion materials have a high absorption rate for sunlight, strong photothermal conversion performance, and a sustained and stable conversion effect. Combining defective copper sulfide with nano-cesium tungsten bronze not only helps to compensate for the insufficient absorption rate of cesium tungsten bronze in the visible light region, but also reduces the probability of electron-hole recombination, prolongs the carrier lifetime, and increases the non-relaxation heat release of carriers, thereby increasing heat output and accelerating surface temperature rise. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0028] Figure 1 The Cs obtained by X-ray diffractometer (XRD) in Example 1, Example 2 and Example 3 of the present invention is 0.32 WO3 / Cu x Comparison of the specific components of S nano-heterojunction photothermal conversion materials at different temperatures;

[0029] Figure 2 is Cs in Example 1, Example 2, and Example 3 of the present invention 0.32 WO3 / Cu x Surface image of S nanoheterojunction photothermal conversion material measured under a scanning electron microscope (SEM);

[0030] Figure 3 is Cs in Example 1, Example 2, and Example 3 of the present invention 0.32 WO3 / Cu x Temperature distribution of the sample of S nanoheterojunction photothermal conversion material measured by an infrared imaging camera under simulated sunlight.

[0031] Figure 4 Cs in Comparative Examples 1 and 2 of the present invention 0.32 WO3 / Cu x The temperature distribution of the sample of S nanophotothermal conversion material measured by an infrared imaging camera under simulated sunlight. DETAILED DESCRIPTION

[0032] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0033] A Cs 0.32 WO3 / Cu x S nano heterojunction photothermal conversion material, composed of cesium tungsten bronze (Cs0.32 WO3) nanoparticles and copper sulfide (Cu x S) to form a heterojunction structure. 0.32 WO3 / Cu x S nano heterojunction photothermal conversion material. If the content of CuS is too low, it will 0.32 The amount of CuS on the surface of WO3 particles is small, resulting in the formation of Cs 0.32 The carrier transfer rate on the surface of WO3 / CuS heterojunction is slow, which affects the efficiency of light-to-heat conversion. On the contrary, if the CuS content is too high, it will cause Cs 0.32 The CuS on WO3 is severely stacked, which prolongs the carrier transmission path, prevents the heat release of hot carriers, reduces the photothermal conversion efficiency, and is not conducive to the heat output of the material.

[0034] A Cs 0.32 WO3 / Cu x The preparation method of S nano heterojunction photothermal conversion material specifically comprises the following steps:

[0035] S1, Cs 0.32 WO3 and Cu(NO3)2 particles were added to ionized water in a mass ratio of 0.6:1 to 2.4:1 and prepared into Cs 0.32 WO3 and Cu(NO3)2 mixed solution, in which Cs 0.32 The concentration of Cu(NO3)2 solution in the mixed solution of WO3 and Cu(NO3)2 is 0.1~0.4g / mL, and Cs 0.32 The mass of WO3 powder is 3-12 g. Then, Na2S is dispersed in deionized water using the same method to prepare a Na2S solution. The concentration of the Na2S aqueous solution is 0.1-0.4 g / mL.

[0036] S2. After the treatment in step S1 is completed, Cs 0.32 The mixed solution of WO3 and Cu(NO3)2 was added to the Na2S solution and mixed evenly by magnetic stirring, and then ultrasonic dispersion was performed to obtain Cu(NO3)2, Cs 0.32 A mixed solution of WO3 and Na2S; the magnetic stirring time is 30 to 90 minutes, and the ultrasonic dispersion treatment time is 30 to 60 minutes;

[0037] S3, after the treatment of step S2 is completed, Cu(NO3)2, Cs 0.32 The mixed solution of WO3 and Na2S is placed in a reactor for hydrothermal treatment at a temperature of 120-180°C and a reaction time of 10-20 hours;

[0038] S4. After the treatment in step S3 is completed, the product is taken out and filtered through a filter paper with a pore size of 30 to 100 μm, and then vacuum dried at a temperature of 40 to 80° C. for 24 to 72 hours to obtain Cs 0.32 WO3 / CuS precursor powder;

[0039] S5, after step S4 is completed, the above Cs 0.32 The WO3 / CuS precursor powder is placed in a tube furnace, the heating rate is set to 5-10℃ / min, the temperature is set to 300-500℃, nitrogen is introduced for 30-60min, and then the tube furnace is started. After calcination for 60-480min, it is washed and dried with CS2 solution to obtain Cs 0.32 WO3 / Cu x S nanoheterojunction photothermal conversion material.

[0040] Example 1

[0041] This embodiment provides a Cs 0.32 WO3 / Cu x The preparation method of S nano heterojunction light-heat conversion material comprises the following steps:

[0042] (1) Cs 0.32 WO3 and Cu(NO3)2 particles were added to ionized water in a mass ratio of 0.6:1 and prepared into Cs 0.32 WO3 and Cu(NO3)2 mixed solution, and then use the same method to disperse Na2S into deionized water to prepare Na2S solution. 0.32 The concentration of Cu(NO3)2 in the mixed solution of WO3 and Cu(NO3)2 is

[0043] 0.1g / mL, the concentration of Na2S solution is 0.1g / mL, Cs 0.32 The mass of WO3 powder is 3g;

[0044] (2) Cs was added in a volume ratio of 1:0.8. 0.32 The mixed solution of WO3 and Cu(NO3)2 was added to the Na2S solution, and mixed evenly by magnetic stirring, and then subjected to ultrasonic dispersion treatment; the magnetic stirring time was 30 minutes, and the ultrasonic dispersion treatment time was 30 minutes to obtain Cu(NO3)2, Cs 0.32 Mixed solution of WO3 and Na2S;

[0045] (3) Cu(NO3)2, Cs 0.32 The mixed solution of WO3 and Na2S was placed in a reactor for hydrothermal treatment at a temperature of 120°C and a reaction time of 10 h.

[0046] (4) The product obtained in step (3) was taken out and filtered through a filter paper with a pore size of 30 μm, and then vacuum dried at a temperature of 40°C for 24 hours to obtain Cs 0.32 WO3 / CuS precursor powder;

[0047] (5) The above Cs 0.32 WO3 / CuS precursor powder was placed in a tube furnace, the heating rate was set to 5℃ / min, the temperature was set to 300℃, nitrogen was introduced for 30 minutes, and the tube furnace was started. After calcination for 60 minutes, it was washed and dried with CS2 solution to obtain Cs 0.32 WO3 / Cu x S nanoheterojunction photothermal conversion material.

[0048] Analysis of Cs 0.32 WO3 / Cu x XRD patterns of S nanoheterojunction photothermal conversion materials, such as Figure 1 As shown, Cs 0.32 After calcination, WO3 / CuS generates Cs 0.32 WO3 / CuS-Cu 1.95 S nano-photothermal conversion material. Observation of Cs 0.32 WO3 / CuS-Cu 1.95 The microscopic morphology of S nano-photothermal conversion materials, such as Figure 2 As shown in (a), the calcined granular CuS-Cu 1.95 S is attached to the rod-shaped Cs 0.32 On WO3, this structure is conducive to the rapid transmission of photogenerated carriers, making the non-relaxation heat release of photogenerated carriers greater. Figure 3 As shown in (a), the infrared camera captures Cs 0.32 WO3 / CuS-Cu 1.95 The temperature of S powder reached 50.6℃ within 5 minutes, indicating that Cs 0.32 WO3 / CuS-Cu 1.95 S nano-photothermal conversion material has good photothermal conversion performance and can make the surface of the material heat up rapidly.

[0049] Example 2

[0050] This embodiment provides a Cs 0.32 WO3 / Cu x The preparation method of S nano heterojunction light-heat conversion material comprises the following steps:

[0051] (1) Cs 0.32 WO3 and Cu(NO3)2 particles were added to ionized water in a mass ratio of 1.2:1 and prepared into Cs 0.32WO3 and Cu(NO3)2 mixed solution, and then using the same method to disperse Na2S into deionized water to prepare Na2S solution. 0.32 The concentration of Cu(NO3)2 in the mixed solution of WO3 and Cu(NO3)2 is

[0052] 0.2g / mL, the concentration of Na2S aqueous solution is 0.2g / mL, Cs 0.32 The mass of WO3 powder is 6g;

[0053] (2) Cs 0.32 The mixed solution of WO3 and Cu(NO3)2 was added to the Na2S solution, and mixed evenly by magnetic stirring, and then subjected to ultrasonic dispersion treatment; the magnetic stirring time was 60 min, and the ultrasonic dispersion treatment time was 45 min, to obtain Cu(NO3)2, Cs 0.32 Mixed solution of WO3 and Na2S;

[0054] (3) Cu(NO3)2, Cs 0.32 The mixed solution of WO3 and Na2S was placed in a reactor for hydrothermal treatment at a temperature of 160°C and a reaction time of 15 h.

[0055] (4) The product obtained in step (3) was taken out and filtered through a filter paper with a pore size of 60 μm, and then vacuum dried at a temperature of 60° C. for 45 h to obtain Cs 0.32 WO3 / CuS precursor powder;

[0056] (5) The above Cs 0.32 WO3 / CuS precursor powder was placed in a tube furnace, the heating rate was set to 8℃ / min, the temperature was set to 400℃, nitrogen was introduced for 40 minutes, and the tube furnace was started. After calcination for 240 minutes, it was washed and dried with CS2 solution to obtain Cs 0.32 WO3 / Cu x S nanoheterojunction photothermal conversion material.

[0057] Analysis of Cs 0.32 WO3 / Cu x XRD patterns of S nanoheterojunction photothermal conversion materials, such as Figure 1 As shown, Cs 0.32 After calcination, WO3 / CuS generates Cs 0.32 WO3 / Cu 1.95 S-Cu2S nano-photothermal conversion material. Observation of Cs 0.32 WO3 / Cu 1.95 The microstructure of S-Cu2S nano-photothermal conversion materials, such as Figure 2(b) shows that slightly larger Cu particles after calcination 1.95 S-Cu2S is attached to the rod-shaped Cs 0.32 On WO3, there is a large heterojunction interface, which is very conducive to the rapid transmission of photogenerated carriers, making the non-relaxation heat release of photogenerated carriers greater. Figure 3 As shown in (b), the infrared camera captures Cs 0.32 WO3 / Cu 1.95 The temperature of S-Cu2S powder reached 52.9℃ within 5min, indicating that Cs 0.32 WO3 / CuS-Cu 1.95 S nano-photothermal conversion material has excellent photothermal conversion performance and can rapidly heat up the surface of the material.

[0058] Example 3

[0059] This embodiment provides a Cs 0.32 WO3 / Cu x The preparation method of S nano heterojunction light-heat conversion material comprises the following steps:

[0060] (1) Cs 0.32 WO3 and Cu(NO3)2 particles were added to ionized water in a mass ratio of 2.4:1 and prepared into Cs 0.32 WO3 and Cu(NO3)2 mixed solution, and then using the same method to disperse Na2S into deionized water to prepare Na2S solution. 0.32 The concentration of Cu(NO3)2 in the mixed solution of WO3 and Cu(NO3)2 is

[0061] 0.4g / mL, the concentration of Na2S aqueous solution is 0.4g / mL, Cs 0.32 The mass of WO3 powder is 12g;

[0062] (2) Cs 0.32 WO3 and Cu(NO3)2 mixed solution was added to Na2S solution, and mixed evenly by magnetic stirring, and then subjected to ultrasonic dispersion treatment; the magnetic stirring time was 90min, and the ultrasonic dispersion treatment time was 60min, to obtain Cu(NO3)2, Cs 0.32 Mixed solution of WO3 and Na2S;

[0063] (3) Cu(NO3)2, Cs 0.32 The mixed solution of WO3 and Na2S was placed in a reactor for hydrothermal reaction. The hydrothermal reduction reaction temperature was 180°C and the reaction time was 20h.

[0064] (4) The product obtained in step (3) was taken out and filtered through a filter paper with a pore size of 100 μm, and then vacuum dried at a temperature of 80° C. for 72 h to obtain Cs 0.32 WO3 / CuS precursor powder;

[0065] (5) The above Cs 0.32 WO3 / CuS precursor powder was placed in a tube furnace, the heating rate was set to 8℃ / min, the temperature was set to 500℃, nitrogen was introduced for 60min, and the tube furnace was started. After calcination for 480min, it was washed and dried with CS2 solution to obtain Cs 0.32 WO3 / Cu x S nanoheterojunction photothermal conversion material.

[0066] Analysis of Cs 0.32 WO3 / Cu x XRD patterns of S nanoheterojunction photothermal conversion materials, such as Figure 1 As shown, Cs 0.32 After calcination, WO3 / CuS generates Cs 0.32 WO3 / Cu2S nano-photothermal conversion material. Observation of Cs 0.32 The microstructure of WO3 / Cu2S nano-photothermal conversion materials, such as Figure 2 As shown in (c), after calcination, large granular Cu2S is attached to the rod-shaped Cs 0.32 On WO3, a stacking structure is generated, which affects the transmission of photogenerated carriers, making the carrier transmission path longer and slightly hindering the non-relaxation heat release of photogenerated carriers. Figure 3 As shown in (c), the infrared camera captures Cs 0.32 The temperature of WO3 / Cu2S powder reached 49.8℃ within 5min, indicating that Cs 0.32 WO3 / Cu2S nano-photothermal conversion material has excellent photothermal conversion performance, which can make the material surface rise to a certain temperature quickly.

[0067] Comparative Example 1

[0068] (1) Cs 0.32 WO3 and Cu(NO3)2 particles were added to ionized water in a mass ratio of 1.2:1 and prepared into Cs 0.32 WO3 and Cu(NO3)2 mixed solution, and then use the same method to disperse Na2S into deionized water to prepare Na2S solution. 0.32 The concentration of Cu(NO3)2 in the mixed solution of WO3 and Cu(NO3)2 is

[0069] 0.2g / mL, the concentration of the Na2S solution is 0.2g / mL, Cs0.32 The mass of WO3 powder is 6g;

[0070] (2) Cs 0.32 The WO3 and Cu(NO3)2 mixed solution was added to the Na2S solution, and the mixture was mixed uniformly by magnetic stirring, and then subjected to ultrasonic dispersion treatment; the magnetic stirring time was 60 minutes, and the ultrasonic dispersion treatment time was 45 minutes;

[0071] (3) Cu(NO3)2, Cs 0.32 The mixed solution of WO3 and Na2S was placed in a reactor for hydrothermal reaction. The hydrothermal reduction reaction temperature was 160°C and the reaction time was 15h.

[0072] (4) The product was taken out and filtered through a filter paper with a pore size of 60 μm, and then vacuum dried at a temperature of 60°C for 45 hours to obtain Cs 0.32 WO3 / CuS precursor powder;

[0073] (5) The above Cs 0.32 The WO3 / CuS precursor powder was placed in a tube furnace, the heating rate was set to 8°C / min, the temperature was set to 200°C, nitrogen was introduced for 40 minutes, and the tube furnace was started. After calcination for 240 minutes, the powder was washed and dried with CS2 solution to obtain Cs 0.32 WO3 / Cu x S nano-photothermal conversion material.

[0074] After calcination at too low a temperature, Cs 0.32 WO3 / Cu x The number of sulfur defects in S nano-photothermal conversion materials is significantly reduced, and Cs 0.32 WO3 and Cu x The S heterojunction interface is also greatly reduced. This structure affects the transmission of photogenerated carriers, making the carrier transmission path longer, which leads to serious obstruction of the non-relaxation heat release of photogenerated carriers. Figure 4 As shown in (a), the infrared thermal imager captured Cs 0.32 WO3 / Cu x The temperature of S powder was only 42.5℃ within 5min, indicating that Cs 0.32 WO3 / Cu x The S-200 nanometer photothermal conversion material has poor photothermal conversion performance, resulting in a low surface temperature of the material.

[0075] Comparative Example 2

[0076] (1) Cs 0.32WO3 and Cu(NO3)2 particles were added to ionized water in a mass ratio of 1.2:1 and prepared into Cs 0.32 WO3 and Cu(NO3)2 mixed solution, and then Na2S was dispersed into deionized water using the same method to prepare Na2S solution. 0.32 The concentration of Cu(NO3)2 in the mixed solution of WO3 and Cu(NO3)2 is

[0077] 0.2g / mL, the concentration of Na2S solution is 0.2g / mL, Cs 0.32 The mass of WO3 powder is 18g;

[0078] (2) Cs 0.32 WO3 and Cu(NO3)2 mixed solution was added to Na2S solution, and mixed evenly by magnetic stirring, and then subjected to ultrasonic dispersion treatment; the magnetic stirring time was 60min, and the ultrasonic dispersion treatment time was 45min, to obtain Cu(NO3)2, Cs 0.32 Mixed solution of WO3 and Na2S;

[0079] (3) Cu(NO3)2, Cs 0.32 The mixed solution of WO3 and Na2S was placed in a reactor for hydrothermal reaction. The hydrothermal reduction reaction temperature was 160°C and the reaction time was 15h.

[0080] (4) The product was taken out and filtered through a filter paper with a pore size of 60 μm, and then vacuum dried at a temperature of 60°C for 45 hours to obtain Cs 0.32 WO3 / CuS precursor powder;

[0081] (5) The above Cs 0.32 WO3 / CuS precursor powder was placed in a tube furnace, the heating rate was set to 8℃ / min, the temperature was set to 600℃, nitrogen was introduced for 40 minutes, and the tube furnace was started. After calcination for 240 minutes, it was washed and dried with CS2 solution to obtain Cs 0.32 WO3 / Cu x S nano-photothermal conversion material.

[0082] After high temperature calcination, Cs 0.32 WO3 and Cu x S has a serious stacking phenomenon, which has a significant impact on the transmission of photogenerated carriers, causing the carrier transmission path to become longer and hindering the non-relaxation heat release of photogenerated carriers. Figure 4 As shown in (b), Cs 0.32 WO3 / Cu xThe temperature of S powder only rose to 44.0℃ within 5min, indicating that Cs 0.32 WO3 / Cu x The S-600 nanometer photothermal conversion material has poor photothermal conversion performance, which causes the surface temperature of the material to rise slowly.

Claims

1. A Cs 0.32 WO3 / Cu x The preparation method of S nano heterojunction photothermal conversion material is characterized in that: First, Cs was prepared by hydrothermal method. 0.32 WO3 / CuS precursor; Cs 0.32 The WO3 / CuS precursor is calcined in a nitrogen atmosphere at a temperature of 300-500°C for 60-400 min to form defective Cs 0.32 WO3 / Cu x S nanoheterojunction photothermal conversion material; The hydrothermal method for preparing Cs 0.32 The steps of WO3 / CuS precursor are as follows: S1, Cs 0.32 WO3 and Cu(NO3)2 particles were added to ionized water in a mass ratio of 0.6:1~2.4:1 and prepared into Cs 0.32 WO3 and Cu(NO3)2 mixed solution, Na2S dispersed in deionized water to prepare Na2S solution; the Cs 0.32 The concentration of Cu(NO3)2 solution in the mixed solution of WO3 and Cu(NO3)2 is 0.1~0.4g / mL, and the concentration of Cs 0.32 WO3 powder 3~12g, Na2S solution concentration 0.1~0.4g / mL; S2. After the step S1 is completed, Cs 0.32 The mixed solution of WO3 and Cu(NO3)2 was added to the Na2S solution and mixed evenly by magnetic stirring, and then ultrasonic dispersion treatment was performed for 120-180 min to obtain Cu(NO3)2, Cs 0.32 Mixed solution of WO3 and Na2S; S3, after the treatment of step S2 is completed, Cu(NO3)2, Cs 0.32 The mixed solution of WO3 and Na2S is placed in a reactor for hydrothermal treatment at a temperature of 120-180°C for 10-20 hours. S4. After step S3, the product is taken out, filtered, and then vacuum dried to obtain Cs 0.32 WO3 / CuS precursor powder.

2. A Cs according to claim 1 0.32 WO3 / Cu x The preparation method of S nano heterojunction photothermal conversion material is characterized in that: In step S2, the magnetic stirring time is 30 to 90 minutes.

3. A Cs according to claim 1 0.32 WO3 / Cu x The preparation method of S nano heterojunction photothermal conversion material is characterized in that: In step S4, suction filtration is adopted, the pore size of the filter paper for suction filtration is 30-100 μm, the vacuum drying temperature is 40-80° C., and the time is 24-72 h.

4. A Cs according to claim 1 0.32 WO3 / Cu x The preparation method of S nano heterojunction photothermal conversion material is characterized in that: Cs 0.32 The WO3 / CuS precursor was calcined in a nitrogen atmosphere and then washed and dried with a CS2 solution at a drying temperature of 60-120°C.

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