Simple preparation method and application of high-dispersion cuprous oxide quantum dots

Abstract

The invention relates to the field of preparation of quantum dot cuprous oxide, in particular to a simple preparation method and application of high-dispersion cuprous oxide quantum dots, and the method comprises the following steps: mechanically grinding commercial P25 serving as a carrier catalyst and copper chloride in an agate mortar, uniformly mixing, adding hydrazine hydrate, continuously grinding for 30 minutes, washing the obtained solid product with deionized water, and drying to obtain the high-dispersion cuprous oxide quantum dots. And drying at room temperature to obtain the cuprous oxide quantum dots uniformly dispersed on the TiO2 carrier. The preparation method of the metal quantum dots is simple and convenient, the raw materials are simple and easy to obtain, repeatability is good, and the metal quantum dots are highly dispersed. The material prepared through the method can remarkably improve the photocatalytic hydrogen evolution and nitrogen reduction efficiency of a carrier catalyst. The method has a wide application value in the creation of the quantum dot catalyst in the field of sustainable energy sources such as photocatalysis.

Description

Technical Field

[0001] The invention belongs to the technical field of quantum dot cuprous oxide preparation, and in particular relates to a simple preparation method and application of highly dispersed cuprous oxide quantum dots. Background Art

[0002] Copper-based compounds are a common photocatalytic additive. The photocatalytic promotion mechanism is based on its own high work function to promote the efficient separation and transfer of photogenerated electrons and holes, thereby effectively improving the photocatalytic efficiency. Among them, cuprous oxide is the compound with the highest copper content among common copper compounds. Studies have shown that the quantum efficiency of bulk cuprous oxide is low. When the particle size changes from micrometer to nanometer or even to quantum level, its excellent light capture and photochemical ability can greatly improve the quantum efficiency of the photocatalytic reaction.

[0003] At present, the main methods for preparing cuprous oxide quantum dots include hot injection, hydrothermal / solvothermal, and sol-gel methods, but their application in the field of photocatalysis still faces the following problems: First, cuprous oxide quantum dots with high surface energy have serious agglomeration; second, the methods still have shortcomings such as poor safety, long reaction time, and complex preparation process. Therefore, it is of practical significance to develop a simple, efficient preparation method that can make cuprous oxide quantum dots highly dispersed and uniformly loaded. Summary of the invention

[0004] The purpose of the present invention is to provide a simple preparation method and application of highly dispersed cuprous oxide quantum dots, so as to solve the problems raised in the background technology and facilitate promotion.

[0005] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0006] A simple method for preparing highly dispersed cuprous oxide quantum dots, characterized in that it comprises the following steps:

[0007] S1: The copper source and the supported catalyst are placed in an agate mortar and mixed evenly, and a reducing agent is added to react to obtain a solid product;

[0008] S2: washing the solid product with distilled water and drying it to obtain the highly dispersed cuprous oxide quantum dots supported on the surface of the carrier catalyst.

[0009] Furthermore, the copper source in S1 is a divalent copper source, and the divalent copper source includes copper chloride, copper nitrate, copper sulfate or copper acetate.

[0010] Furthermore, the supported catalyst includes P25, C3N4, and ZnO, and the molar ratio of the supported catalyst to the copper source is 1:0.5%-2.5%.

[0011] Furthermore, the reducing agent described in S1 includes hydrazine hydrate, ascorbic acid and sodium borohydride, the amount of hydrazine hydrate is 1-10mL, the amount of ascorbic acid is 0.5-5mmol, and the amount of sodium borohydride is 0.5-5mmol.

[0012] Furthermore, the reaction temperature in S1 is 10-35°C.

[0013] An application of highly dispersed cuprous oxide quantum dots, including the application of highly dispersed cuprous oxide quantum dots as a photocatalytic material, is characterized in that the method is as follows: the highly dispersed cuprous oxide quantum dot material loaded on the surface of a carrier catalyst is uniformly dispersed in a methanol solution and irradiated with light under simulated sunlight conditions.

[0014] Furthermore, the highly dispersed cuprous oxide quantum dot material supported on the surface of the carrier catalyst is uniformly dispersed in a methanol solution, and after nitrogen is continuously introduced for half an hour, light irradiation is performed under simulated sunlight conditions.

[0015] Furthermore, the amount of the highly dispersed cuprous oxide quantum dot material loaded on the surface of the carrier catalyst is 20-100 mg.

[0016] Furthermore, the volume ratio of water to methanol in the methanol solution is 1:0.7ml-0.95ml.

[0017] As an improvement, the beneficial effects of the present invention are:

[0018] (1) The method for preparing highly dispersed cuprous oxide quantum dots provided in the present application is simple to operate, and the reaction process does not require heating or pressurization, which is beneficial to energy conservation and emission reduction; the reaction system used is a solid phase, the reactants are solid phase, the process is simple, the copper source in the reactants can be completely converted into cuprous oxide, and the cost is low; through the synergistic effect of reducing agents such as hydrazine hydrate, the synthesized nano-crystallinity, uniform size, high dispersion, strong photocatalytic activity, and good catalytic effect are achieved.

[0019] (2) The highly dispersed cuprous oxide quantum dots provided in the present application have a particle size that can be controlled within the range of 1 to 3 nm. After being placed at room temperature and pressure for 30 days, the cuprous oxide quantum dots are still highly dispersed.

[0020] (3) The highly dispersed cuprous oxide quantum dots loaded on the carrier catalyst prepared in the present application exhibit excellent catalytic performance and can be widely used in the field of photocatalysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a high-angle annular dark field scanning transmission electron microscope image (HAADF-STEM) of a cuprous oxide quantum dot catalyst with TiO2 or the like as a carrier prepared in Example 1 of the present invention, with a scale of 5 nm;

[0022] Figure 2 This is the XRD diffraction pattern of cuprous oxide quantum dots prepared in Example 5 of the present invention;

[0023] Figure 3 This is a photocatalytic hydrogen evolution performance diagram of the cuprous oxide quantum dot catalyst with TiO2 as a carrier prepared in Example 1 of the present invention after 5 hours of illumination;

[0024] Figure 4 This is a performance diagram of a photocatalytic hydrogen evolution cycle test of a cuprous oxide quantum dot catalyst with TiO2 or the like as a carrier prepared in Example 1 of the present invention, with each reaction lasting 5 hours under illumination conditions and 10 cycles of recycling;

[0025] Figure 5 The cuprous oxide quantum dot catalyst prepared in Example 1 of the present invention with TiO2 as a carrier, photocatalytically reduces N2 to NH4 after 2.5 hours of illumination. + Performance graphs;

[0026] Figure 6 This is a performance diagram of a photocatalytic nitrogen N2 reduction recycling cycle test of a cuprous oxide quantum dot catalyst with TiO2 or the like as a carrier prepared in Example 1 of the present invention, with each reaction lasting 5 hours and three recycling cycles under light irradiation conditions; DETAILED DESCRIPTION

[0027] In order to make the contents of the present invention more clearly understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0028] Embodiment 1:

[0029] A simple preparation method for highly dispersed cuprous oxide quantum dots, the steps are as follows:

[0030] (1) 0.5% copper chloride and 500 mg of commercial P25 were placed in an agate mortar and mixed evenly, and then 1-10 mL of hydrazine hydrate was added dropwise and ground continuously until completely dry.

[0031] (2) The solid product was washed with deionized water and dried at room temperature to obtain a light blue sample.

[0032] Embodiment 2:

[0033] (1) 1% copper chloride and 500 mg of commercial P25 were placed in an agate mortar and mixed evenly, and then 1-10 mL of hydrazine hydrate was added dropwise and ground continuously until completely dry.

[0034] (2) The solid product was washed with deionized water and dried at room temperature to obtain a light blue sample.

[0035] Embodiment 3:

[0036] (1) 1.5% copper chloride and 500 mg of commercial P25 were placed in an agate mortar and mixed evenly, and then 1-10 mL of hydrazine hydrate was added dropwise and ground continuously until completely dry.

[0037] (2) The solid product was washed with deionized water and dried at room temperature to obtain a light blue sample.

[0038] Embodiment 4:

[0039] (1) 2% copper chloride and 500 mg of commercial P25 were placed in an agate mortar and mixed evenly, and then 1-10 mL of hydrazine hydrate was added dropwise and ground continuously until completely dry.

[0040] (2) The solid product was washed with deionized water and dried at room temperature to obtain a light blue sample.

[0041] Embodiment 5:

[0042] A simple preparation method for highly dispersed cuprous oxide quantum dots, the steps are as follows:

[0043] (1) Place 100% copper chloride in an agate mortar and grind it into fine powder. Then add 3 mL of hydrazine hydrate and continue grinding until it is completely dry.

[0044] (2) The solid product was washed with deionized water and dried at room temperature to obtain a brick red sample.

[0045] Embodiment 6:

[0046] A simple preparation method for highly dispersed cuprous oxide quantum dots, the steps are as follows:

[0047] (1) Place 0% copper chloride and 500 mg of commercial TiO2 in an agate mortar, mix well, then drop 1-10 mL of hydrazine hydrate and continue grinding until completely dry.

[0048] (2) The solid product was washed with deionized water and dried at room temperature to obtain a white sample.

[0049] Experimental Example 1:

[0050] The high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) image of the highly dispersed cuprous oxide quantum dots loaded on the TiO2 surface obtained in Example 3 is as follows: Figure 1 As shown, the TiO2 size is about 25nm, and the cuprous oxide quantum dots are evenly distributed with a size of about 1-2nm.

[0051] Experimental Example 2:

[0052] The cuprous oxide XRD pattern obtained in Example 5 is as follows Figure 2 As shown, the diffraction peak of the cuprous oxide completely corresponds to the standard card diffraction peak of Cu2O PDF#77-0199, and the characteristic peak of XRD is obvious, which shows that the prepared cuprous oxide has a high crystallinity.

[0053] Experimental Example 3:

[0054] The samples obtained in Examples 1, 2, 3, 4, and 6 were tested for photocatalytic performance. Figure 3 As shown, the photocatalytic hydrogen production efficiency shows a volcano plot trend of first increasing and then decreasing with the increase of Cu content. When the introduction amount of copper chloride is 1.5%, the total hydrogen production reaches 41.85mmol / g, which is 64 times that of the carrier catalyst TiO2.

[0055] Experimental Example 4:

[0056] The samples obtained in Example 3 were tested for photocatalytic cycle performance. Figure 4 As shown, after 50 hours of photocatalytic hydrogen evolution recovery cycle test, its catalytic hydrogen evolution efficiency still remained above 82%, indicating good cycle recovery stability.

[0057] Experimental Example 5:

[0058] The samples obtained in Examples 3 and 6 were tested for photocatalytic performance. Figure 5 As shown in the figure, the photocatalytic N2 reduction efficiency is significantly increased due to the introduction of Cu. When the amount of copper chloride introduced is 1.5%, the photocatalytic N2 reduction of NH4 + The total amount is as high as 435.5μmol / g. After three recycling cycles, its catalytic N2 reduction efficiency still remains above 98%, indicating good recycling stability.

[0059] Experimental Example 6:

[0060] The samples obtained in Example 3 were tested for photocatalytic N2 reduction cycle performance. Figure 6 As shown, after three photocatalytic N2 reduction recovery cycle tests, its catalytic efficiency still remained above 98%, indicating good cycle recovery stability.

[0061] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A simple method for preparing highly dispersed cuprous oxide quantum dots, characterized in that: The following steps are involved: S1: The copper source and the supported catalyst are placed in an agate mortar and mixed evenly, and a reducing agent is added to react to obtain a solid product; S2: washing the solid product with distilled water and drying it to obtain the highly dispersed cuprous oxide quantum dots supported on the surface of the carrier catalyst.

2. A simple preparation method for highly dispersed cuprous oxide quantum dots according to claim 1, characterized in that: The copper source in S1 is a divalent copper source, and the divalent copper source includes copper chloride, copper nitrate, copper sulfate or copper acetate.

3. A simple preparation method for highly dispersed cuprous oxide quantum dots according to claim 1, characterized in that: The supported catalyst comprises P25, C3N4 and ZnO, and the molar ratio of the supported catalyst to the copper source is 1:0.5%-2.5%.

4. The simple preparation method of highly dispersed cuprous oxide quantum dots according to claim 1, characterized in that: The reducing agent described in S1 includes hydrazine hydrate, ascorbic acid and sodium borohydride, the amount of hydrazine hydrate is 1-10mL, the amount of ascorbic acid is 0.5-5mmol, and the amount of sodium borohydride is 0.5-5mmol.

5. A simple preparation method for highly dispersed cuprous oxide quantum dots according to claim 1, characterized in that: The reaction temperature in S1 is 10-35°C.

6. Highly dispersed cuprous oxide quantum dots are prepared according to the preparation method according to any one of claims 1 to 5.

7. An application of highly dispersed cuprous oxide quantum dots, including the application of highly dispersed cuprous oxide quantum dots as photocatalytic materials, characterized in that: The application of the highly dispersed cuprous oxide quantum dots as a photocatalytic material includes a photocatalytic hydrogen production performance test and a photocatalytic nitrogen fixation performance test. The photocatalytic hydrogen production performance test requires adding the highly dispersed cuprous oxide quantum dot material loaded on the surface of the carrier catalyst into a methanol solution for dispersion and irradiation.

8. The use of highly dispersed cuprous oxide quantum dots according to claim 7, characterized in that: In the photocatalytic nitrogen fixation performance test, the highly dispersed cuprous oxide quantum dot material loaded on the surface of the carrier catalyst is evenly dispersed in a methanol solution, nitrogen is passed through for half an hour to ensure nitrogen saturation, and then light irradiation is started.

9. The use of a highly dispersed cuprous oxide quantum dots according to claim 7, characterized in that: The dosage of the highly dispersed cuprous oxide quantum dot material loaded on the surface of the carrier catalyst is 20-100 mg.

10. The use of highly dispersed cuprous oxide quantum dots according to claim 7, characterized in that: The volume ratio of water to methanol in the methanol solution is 1:0.7ml-0.95ml.

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