Preparation method and application of CdS / NiPc heterojunction composite photocatalyst
By growing CdS nanoparticles on NiPc rod-like structures to construct a CdS/NiPc heterojunction photocatalyst, the problems of low light utilization efficiency and electron-hole recombination of the photocatalyst were solved, and efficient photocatalytic oxygen reduction to produce H2O2 was achieved.
Patent Information
- Application Number
- CN202511169044.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-20
- Publication Date
- 2025-10-10
AI Technical Summary
Existing photocatalysts have low light utilization efficiency and easy recombination of photogenerated electrons and holes when producing H2O2, which cannot meet the needs.
CdS nanoparticles were grown on NiPc rod-like structures by a hydrothermal method to construct a CdS/NiPc heterojunction composite photocatalyst, which enhanced the light energy capture efficiency and charge separation efficiency.
It achieves efficient photocatalytic oxygen reduction to produce H2O2, has strong visible light absorption ability and efficient charge separation ability, and improves the H2O2 generation rate.
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Figure CN120754896A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application relates to the technical field of photocatalytic materials, in particular to a preparation method and application of a CdS / NiPc heterojunction composite photocatalyst. BACKGROUND
[0002] H2O2 is widely used in many fields as an efficient and environmentally friendly energy carrier and oxidant, such as fuel cells, textile bleaching and wastewater treatment; at present, the industrial production method of H2O2 is mainly anthraquinone method, and the process is relatively complex, the cost is high, and the shortcomings such as emission of pollutants limit its wide application. Therefore, it is urgent to find an efficient and low-cost method for producing hydrogen peroxide.
[0003] Solar photocatalytic production of H2O2 as a new preparation method has attracted widespread attention due to its environmental friendliness and economic efficiency. Compared with the traditional anthraquinone method, this technology directly uses solar energy to drive the reaction of oxygen and water, and there is no pollutant emission in the whole process, and it can be carried out under mild conditions (normal temperature and pressure). However, single-component photocatalysts face the problems of low light utilization efficiency and easy recombination of photo-generated electrons and holes, which cannot meet the demand of H2O2 production. How to simultaneously improve the light energy capture efficiency and charge separation efficiency of photocatalysts through structure design (such as construction of heterojunction, introduction of defect sites), element doping or cocatalyst modification has become the core research direction to promote the practical application of this technology, and related research results have also continued to occupy the research hotspot in the field of catalysis. SUMMARY
[0004] In order to solve at least part of the problems in the background art, the application provides a preparation method and application of a CdS / NiPc heterojunction composite photocatalyst.
[0005] The first aspect of the application provides a preparation method of a CdS / NiPc heterojunction composite photocatalyst, which comprises growing CdS material on NiPc by a hydrothermal method to prepare the CdS / NiPc heterojunction composite photocatalyst.
[0006] Further, the CdS / NiPc heterojunction composite photocatalyst is prepared by growing CdS material on NiPc through a hydrothermal method, which comprises the following steps.
[0007] Dissolve a cadmium source and a sulfur source in deionized water to obtain a CdS dissolving solution;
[0008] Add NiPc to the CdS dissolving solution and stir to obtain a mixed solution;
[0009] Heat the mixed solution to perform a hydrothermal reaction to obtain a precipitate, and the precipitate is the CdS / NiPc heterojunction composite photocatalyst.
[0010] Further, the cadmium source is at least one of cadmium acetate and cadmium nitrate.
[0011] Further, the sulfur source is at least one of thiourea and sodium sulfide.
[0012] Further, the dissolving of the cadmium source and the sulfur source in the deionized water to obtain the CdS solution includes:
[0013] The cadmium source powder and the sulfur source powder are put into the deionized water at a molar ratio of 1:10, and are stirred and dissolved at a rotation speed of 500 r / min at room temperature to obtain the CdS solution.
[0014] Further, the adding of the NiPc into the CdS solution to obtain a mixed solution includes:
[0015] The NiPc with a mass of 3% to 15% of the mass of the cadmium source is added into the CdS solution, and is stirred at room temperature to obtain the mixed solution.
[0016] Further, the adding amount of the NiPc is 10% of the mass of the cadmium source.
[0017] Further, the heating of the mixed solution to perform a hydrothermal reaction to obtain a precipitate includes:
[0018] The mixed solution is transferred into a hydrothermal synthesis reactor, and is subjected to a hydrothermal reaction at 150°C to 170°C for at least 4 hours to obtain the precipitate.
[0019] Further, after the precipitate is obtained, the method further includes:
[0020] The precipitate is sequentially washed and dried to obtain the dark green CdS / NiPc heterojunction composite photocatalyst.
[0021] The second aspect of the application provides an application of the CdS / NiPc heterojunction composite photocatalyst, and the CdS / NiPc heterojunction composite photocatalyst prepared by the preparation method of the CdS / NiPc heterojunction composite photocatalyst is applied to the photocatalytic production of H2O2.
[0022] The application has the following beneficial effects:
[0023] The novel CdS / NiPc heterojunction composite photocatalyst prepared by the application is grown on the NiPc rod structure by a hydrothermal method, a novel CdS / NiPc heterojunction material is successfully constructed, and compared with a single component, has strong visible light absorption capacity, efficient charge separation capacity and enhanced redox capacity, and is beneficial to realize efficient photocatalytic oxygen reduction to produce H2O2. BRIEF DESCRIPTION OF DRAWINGS
[0024] Figure 1 A flowchart of a preparation method of a CdS / NiPc heterojunction composite photocatalyst is shown in the figure.
[0025] Figure 2 XRD patterns of the new CdS / NiPc heterojunction composite photocatalyst in the comparative example and examples 1-3 of the present application are shown in the figure.
[0026] Figure 3 A SEM image of the new CdS / NiPc heterojunction composite photocatalyst in example 1 of the present application is shown in the figure.
[0027] Figure 4 A TEM image of the new CdS / NiPc heterojunction composite photocatalyst in example 1 of the present application is shown in the figure.
[0028] Figure 5 A HRTEM image of the new CdS / NiPc heterojunction composite photocatalyst in example 1 of the present application is shown in the figure.
[0029] Figure 6 A UV-Vis diffuse reflectance spectrum of the new CdS / NiPc heterojunction composite photocatalyst in the comparative example and examples 1-3 of the present application is shown in the figure.
[0030] Figure 7 A visible light catalytic hydrogen peroxide production rate graph of the new CdS / NiPc heterojunction composite photocatalyst in the comparative example and examples 1-3 of the present application is shown in the figure.
[0031] Figure 8 A visible light catalytic hydrogen peroxide production rate graph of the new CdS / NiPc heterojunction composite photocatalyst in example 1 of the present application under different gas environment conditions is shown in the figure.
[0032] Figure 9 A photocatalytic cycle stability graph of the new CdS / NiPc heterojunction composite photocatalyst in example 1 of the present application is shown in the figure.
[0033] Figure 10 A visible light catalytic hydrogen peroxide production rate calculation formula of the new CdS / NiPc heterojunction composite photocatalyst in the comparative example and examples 1-3 of the present application is shown in the figure. DETAILED DESCRIPTION
[0034] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the figures and examples. It should be understood that the specific examples described herein are only used to explain the present application, and are not used to limit the present application.
[0035] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "front", "rear", "vertical", "horizontal", "inside", "outside" and the like, indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the devices or components referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as limiting the present invention; the terms "first", "second" and "third" are only used for descriptive purposes and should not be understood as indicating or implying relative importance; in addition, unless otherwise expressly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, an indirect connection through an intermediate medium, or a communication between the internal parts of two components. For those skilled in the art, the specific meanings of the terms in the present invention can be understood according to the specific circumstances.
[0036] See also Figure 1 This embodiment discloses a method for preparing a CdS / NiPc heterojunction composite photocatalyst, comprising:
[0037] S1. Dissolving a cadmium source and a sulfur source in deionized water to obtain a CdS solution;
[0038] S2, adding NiPc to the CdS solution and stirring to obtain a mixed solution;
[0039] S3. Heating the mixed solution to perform a hydrothermal reaction to obtain a precipitate, which is the CdS / NiPc heterojunction composite photocatalyst.
[0040] The novel CdS / NiPc heterojunction composite photocatalyst prepared in this scheme was successfully constructed by growing CdS nanoparticles on NiPc rod-like structures through a hydrothermal method. Compared with a single component, it has strong visible light absorption ability, efficient charge separation ability and enhanced redox ability, which is conducive to the efficient photocatalytic oxygen reduction to produce H2O2.
[0041] This embodiment also discloses an application of a CdS / NiPc heterojunction composite photocatalyst, in which the CdS / NiPc heterojunction composite photocatalyst prepared by the above-mentioned preparation method of the CdS / NiPc heterojunction composite photocatalyst is applied to the photocatalytic production of H2O2.
[0042] The novel CdS / NiPc heterojunction composite photocatalyst prepared in this scheme demonstrates efficient oxygen reduction to produce H2O2. The in situ growth method ensures close contact between the CdS and NiPc interfaces, promoting the formation of Ni-S bonds and improving charge transfer efficiency. During the construction of the CdS / NiPc heterojunction material, electrons transfer from CdS to NiPc, creating a built-in electric field at the interface. During illumination, weakly reducing electrons in the NiPc LUMO (lowest unoccupied molecular orbital) recombine with holes in the CdS VB (valence band), while electrons with strong reducing ability in the CdS CB (conduction band) remain. Consequently, the novel CdS / NiPc heterojunction composite photocatalyst not only effectively enhances the separation efficiency of photogenerated charges but also maintains strong redox activity. More O2 is reduced in the CdS conduction band, further increasing the photocatalytic production rate of H2O2.
[0043] Comparative Example
[0044] Preparation of CdS:
[0045] 640 mg of (CH3COO)2Cd·2H2O cadmium acetate dihydrate and 1.83 g of CH4N2S thiourea powder were added to 30 mL of deionized water and dissolved at room temperature with stirring at 500 rpm. The mixture was then transferred to a 50 mL polytetrafluoroethylene liner and hydrothermaled to 160°C for 4 hours. After cooling, the resulting precipitate was washed three times with deionized water and ethanol, respectively, and collected by centrifugation. Finally, the mixture was dried at 60°C for 10 hours and ground to obtain an orange CdS cadmium sulfide powder, which was compared with a CdS / NiPc heterojunction composite photocatalyst.
[0046] Example 1
[0047] Preparation of CdS / NiPc heterojunction composite photocatalyst:
[0048] 640 mg of (CH3COO)2Cd·2H2O cadmium acetate dihydrate and 1.83 g of CH4N2S thiourea powder were added to 30 mL of deionized water and stirred at 500 rpm at room temperature to dissolve. Then, 64 mg of nickel phthalocyanine (NiPc) powder was added and stirred overnight. The mixture was transferred to a 50 mL polytetrafluoroethylene (PTFE) liner and hydroheated to 160°C for 4 hours. After cooling, the resulting precipitate was washed three times with deionized water and ethanol, respectively, and collected by centrifugation. Finally, it was dried at 60°C for 10 hours and ground to obtain a dark green CdS / NiPc heterojunction composite photocatalyst powder, designated CdS / NiPc-10%.
[0049] Example 2
[0050] Preparation of CdS / NiPc heterojunction composite photocatalyst:
[0051] 640 mg of (CH3COO)2Cd-2H2O cadmium acetate and 1.83 g of CH4N2S thiourea powder were added to 30 mL of deionized water, stirred at 500 r / min at room temperature to dissolve, then 19.2 mg of nickel phthalocyanine NiPc powder was added and continued to stir overnight; transferred to a 50 ml Teflon liner, the hydrothermal temperature was 160°C and kept for 4h, after cooling the obtained precipitate was washed with deionized water and ethanol three times and collected by centrifugation. Finally, after drying at 60°C for 10h, grinding, a dark green CdS / NiPc heterojunction composite photocatalyst powder was obtained, named CdS / NiPc-3%.
[0052] Example 3
[0053] Preparation of CdS / NiPc heterojunction composite photocatalyst:
[0054] 640 mg of (CH3COO)2Cd-2H2O cadmium acetate and 1.83 g of CH4N2S thiourea powder were added to 30 mL of deionized water, stirred at 500 r / min at room temperature to dissolve, then 96 mg of nickel phthalocyanine NiPc powder was added and continued to stir overnight; transferred to a 50 ml Teflon liner, the hydrothermal temperature was 160°C and kept for 4h, after cooling the obtained precipitate was washed with deionized water and ethanol three times and collected by centrifugation. Finally, after drying at 60°C for 10h, grinding, a dark green CdS / NiPc heterojunction composite photocatalyst powder was obtained, named CdS / NiPc-15%.
[0055] Table 1. (CH3COO)2Cd-2H2O, CH4N2S and NiPc addition amount in Examples 1-3
[0056]
[0057] Sample characterization:
[0058] The CdS, NiPc, CdS / NiPc-3%, CdS / NiPc-10% and CdS / NiPc-15% prepared in the comparative examples and examples were subjected to material characterization, and the XRD patterns as shown in Figure 2 , the SEM as shown in Figure 3 , the TEM and HRTEM images as shown in Figure 4 and Figure 5 Figure 6 The UV-vis graph shown in the figure. XRD tests were performed using a Rigaku SmartLab 9kW X-ray powder diffractometer from Japan, SEM tests were performed using a Zeiss Gemini 300 scanning electron microscope from Germany, TEM and HRTEM tests were performed using a Thermo Fisher Scientific field emission transmission electron microscope (TMO Talos F200X), and UV-vis tests were performed using a Shimadzu UV-2600 spectrophotometer from Japan.
[0059] The CdS / NiPc-10% prepared in Example 1 is used as an example for description.
[0060] Depend on Figure 2 The XRD spectrum of the CdS / NiPc composite material shows that the characteristic diffraction peaks are 15.4°, 24.8°, 26.5°, 28.2°, 43.7°, 47.8°, and 52.8°, which correspond to the (102) crystal plane of NiPc and the (100), (002), (101), (110), (103), and (201) crystal planes of CdS (JCPDS 77-2306), respectively. The XRD spectrum of the CdS / NiPc composite material is in good agreement with the spectrum of CdS and NiPc, and no impurity peaks are detected. Figure 3 and Figure 4 The CdS sample is spherical, approximately 1-2 μm in size, while the pristine NiPc exhibits rod-like structures of varying lengths, approximately 2-5 μm in size. SEM analysis clearly demonstrates that the CdS / NiPc-10% composite is a composite of CdS nanoparticles nucleated on rod-shaped NiPc. The close contact between the two materials facilitates electron transport. Figure 5 The lattice fringes of CdS and NiPc can be observed in the high-resolution transmission electron microscope. It can be seen that the lattice spacing of CdS and NiPc is 0.35nm and 1.20nm, respectively, corresponding to the (002) interface of CdS and the (100) interface of NiPc, respectively. At the same time, the result shows a clearer organic / inorganic interface between CdS and NiPc, providing strong evidence for the successful construction of CdS / NiPc heterojunction.
[0061] Figure 6 The UV-visible diffuse reflectance spectrum is shown. It can be seen that with the increase of NiPc content, the light absorption performance of the composite sample gradually increases compared with pure CdS, indicating that combining the two can increase the light absorption range in the visible light region, thereby improving the photocatalytic activity.
[0062] Performance test of visible light catalytic production of hydrogen peroxide:
[0063] The performance test of hydrogen peroxide production of the photocatalyst prepared in this example was conducted using a multi-channel photocatalytic reactor (PCX50C, Perfect Light Co., China) manufactured by Beijing Perfect Light Technology Co., Ltd. The light source used was a 10W LED light source (λ≥420nm, 300mW / cm 2 ).
[0064] The specific steps are as follows:
[0065] 1. Suspend 5 mg of the catalyst in 40 ml of an aqueous solution containing 10 vol% isopropanol and bubble O2 into the reaction flask for 30 min to obtain an O2-saturated environment.
[0066] 2. Stir in the dark for 30 minutes to reach adsorption equilibrium. Then, photocatalytically generate H2O2 in a multi-channel photocatalytic reactor at an ambient temperature of 25°C.
[0067] 3. Determine the amount of H2O2 using the N,N-diethyl-1,4-phenylenediamine method.
[0068] Specifically, 1 mL of the suspension was collected every 30 minutes and filtered through a 0.22 μm water filter to remove the catalyst. The suspension was then mixed with 3 mL of phosphate buffer, 0.3 mL of N,N-diethyl-1,4-phenylenediamine (DPD, 10 g / L), and 0.3 mL of peroxidase (POD, 1 g / L). The color of the solution quickly changed from colorless to deep red. After shaking to achieve uniform color distribution, the absorbance of the solution at 551 nm was measured using a UV / Vis spectrophotometer.
[0069] Phosphate buffer is a mixture of 0.1M Na₂HPO₄ and 0.1M NaH₂PO₄. Dissolve 0.1g DPD in 10mL deionized water to prepare a 10g / L DPD stock solution. Dissolve 10mg POD in 10mL deionized water to prepare a 1g / L peroxidase (POD) solution. Refrigerate. DPD and POD should be prepared fresh and stored for no more than one week.
[0070] The formula for calculating H2O2 concentration is as follows Figure 10 As shown. The correlation coefficient is high (R 2 =0.9998), indicating that the working curve is accurate and reliable.
[0071] The test was conducted using 5 mg of photocatalyst. The test steps were basically the same as those for the photocatalytic activity test. The photocatalytic activity was measured every 30 minutes after continuous illumination for 3 hours. The experimental results showed that the CdS / NiPc-10% composite photocatalyst could produce hydrogen peroxide at a rate of 34.4 mmol·g after 1 hour of illumination. -1 ·L -1, has high visible light photocatalytic activity for producing hydrogen peroxide and good photocatalytic stability.
[0072] Figure 7 The results show the effect of different NiPc addition amounts on the performance of composite photocatalyst for hydrogen peroxide production. Figure 8 As can be seen in the figure, after being combined with NiPc, the hydrogen peroxide production activity of the CdS / NiPc photocatalyst was significantly enhanced compared to the original CdS. Furthermore, the relationship between the amount of NiPc added and the hydrogen peroxide production performance of the composite photocatalyst showed a volcano-shaped relationship. When the mass of the combined NiPc was 10% of the CdS mass, the hydrogen peroxide production performance of the composite photocatalyst reached its peak. As the combined amount continued to increase, its hydrogen peroxide production performance gradually decreased.
[0073] As a comparison, Figure 8 The hydrogen peroxide production rates of the CdS / NiPc-10% composite photocatalyst, when combined with 10wt% NiPc, in different gas atmospheres are shown. It can be seen that in an oxygen-rich atmosphere, the CdS / NiPc-10% H2O2 production rate is highest under visible light. The yield decreases significantly in air and is almost completely suppressed in nitrogen. This indicates that CdS / NiPc-10% has greater potential for photocatalytic hydrogen peroxide production under oxygen-saturated conditions.
[0074] Photocatalytic stability test:
[0075] The best performing CdS / NiPc-10% sample was selected as the subject of the cyclic test. After one test, the catalyst was washed and centrifuged for reuse. The sample was then placed back into the reactor and oxygenated for 30 minutes to achieve oxygen saturation. The light exposure was then continued and the cyclic test was repeated four times to test its photostability. Figure 9 Results are shown. As shown, the CdS / NiPc-10% sample remained stable throughout at least four photocatalytic runs. It can also be observed that the H2O2 concentration in the fourth run only slightly decreased compared to the first run. The significant decrease in photocatalytic performance corresponds to photocatalyst loss caused by friction during the stirred photocatalytic reaction and multiple photocatalyst recycling. These results demonstrate that the prepared CdS / NiPc-10% photocatalyst exhibits good cycling performance and physicochemical stability.
[0076] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.
Claims
1. A method for preparing a CdS / NiPc heterojunction composite photocatalyst, characterized in that: CdS material was grown on NiPc by a hydrothermal method to prepare a CdS / NiPc heterojunction composite photocatalyst.
2. The method for preparing the CdS / NiPc heterojunction composite photocatalyst according to claim 1, characterized in that: The method of growing CdS material on NiPc by a hydrothermal method to prepare a CdS / NiPc heterojunction composite photocatalyst comprises: dissolving a cadmium source and a sulfur source in deionized water to obtain a CdS solution; Adding NiPc to the CdS solution and stirring to obtain a mixed solution; The mixed solution is heated to perform a hydrothermal reaction to obtain a precipitate, which is the CdS / NiPc heterojunction composite photocatalyst.
3. The method for preparing the CdS / NiPc heterojunction composite photocatalyst according to claim 2, characterized in that: The cadmium source is at least one of cadmium acetate and cadmium nitrate.
4. The method for preparing the CdS / NiPc heterojunction composite photocatalyst according to claim 2, characterized in that: The sulfur source is at least one of thiourea and sodium sulfide.
5. The method for preparing the CdS / NiPc heterojunction composite photocatalyst according to claim 2, characterized in that: The step of dissolving the cadmium source and the sulfur source in deionized water to obtain a CdS solution comprises: The cadmium source powder and the sulfur source powder were added into deionized water in a molar ratio of 1:10, and stirred and dissolved at room temperature at a speed of 500 r / min to obtain the CdS solution.
6. The method for preparing the CdS / NiPc heterojunction composite photocatalyst according to claim 2, characterized in that: The step of adding NiPc to the CdS solution and stirring to obtain a mixed solution comprises: Add NiPc whose mass is 3% to 15% of the mass of the cadmium source to the CdS solution, and stir at room temperature to obtain the mixed solution.
7. The method for preparing the CdS / NiPc heterojunction composite photocatalyst according to claim 6, characterized in that: The added amount of NiPc is 10% of the mass of the cadmium source.
8. The method for preparing the CdS / NiPc heterojunction composite photocatalyst according to claim 2, characterized in that: The step of heating the mixed solution to perform a hydrothermal reaction to obtain a precipitate comprises: The mixed solution is transferred to a hydrothermal synthesis reactor, and a hydrothermal reaction is carried out at 150° C. to 170° C. for at least 4 hours to obtain the precipitate.
9. The method for preparing the CdS / NiPc heterojunction composite photocatalyst according to claim 2, characterized in that: After obtaining the precipitate, the method further comprises: The precipitate is washed and dried in sequence to obtain the dark green CdS / NiPc heterojunction composite photocatalyst.
10. An application of a CdS / NiPc heterojunction composite photocatalyst, characterized in that: The CdS / NiPc heterojunction composite photocatalyst prepared by the preparation method of the CdS / NiPc heterojunction composite photocatalyst according to any one of claims 1 to 9 is used for photocatalytic production of H2O2.