A heterogeneous structure and its preparation method and application

Abstract

The present invention belongs to the technical field of photocatalytic materials, and specifically relates to a heterostructure and a preparation method and application thereof. The heterostructure is a Cu2O / Cu / GaON heterostructure formed by compounding Cu2O with Cu and then with GaON. The heterostructure increases the transfer of charges, and the Cu intermediate layer greatly increases the light absorption efficiency, and the catalytic activity thereof is greatly increased compared with the Cu2O material, and the photolysis water efficiency is relatively high.

Description

Technical Field

[0001] The invention belongs to the technical field of photocatalytic materials, and in particular relates to a heterogeneous structure and a preparation method and application thereof. Background Art

[0002] With the massive consumption of fossil fuels, severe environmental and energy problems have arisen, so the development of clean, environmentally friendly, and renewable energy is urgent. Hydrogen energy has the advantages of high energy density, clean products, and high combustion calorific value, and is considered to be an ideal substitute for traditional fossil fuels. Among the many preparation methods, photolysis of water to produce hydrogen has a simple process and clean products. It is a way to obtain efficient hydrogen, but its reaction kinetics are slow and the preparation process consumes extra energy, so the addition of highly active catalysts is key.

[0003] At present, precious metals have the best catalytic performance, but their high price and small reserves hinder their commercial application. Developing non-precious metal catalysts with abundant resources, high efficiency and outstanding stability to replace precious metals can achieve large-scale production in the future. Cu2O is a P-type semiconductor that can absorb visible light. It has the advantages of non-toxicity, diverse and controllable synthesis methods, but its weak photocatalytic activity limits the application of Cu2O in the fields of environment and energy. In particular, a layer of ultra-thin film with a large energy barrier will be formed on the surface of Cu2O, which is not conducive to the generation and transfer of charges when illuminated. Constructing heterojunctions is usually an effective means to improve photocatalytic activity, such as Cu2O composites with metals, semiconductors, carbon, etc. However, in some common composite structures such as Au / Cu2O, ZnO / Cu2O and other photocatalysts, the improvement of catalytic activity is not very ideal. Therefore, for Cu2O, constructing a binary heterostructure is not the most effective way to solve the problem. How to effectively improve the efficiency of Cu2O-based photocatalysts is a technical problem that technicians in this field have been committed to studying and eager to solve. In the prior art, Cu2O is used in combination with metals to effectively improve the catalyst's absorption of light, but it is easy to fail under the effect of photocorrosion during use. When corrosion-resistant materials are combined with Cu2O to construct a heterostructure, its absorption and increase of light are not obvious, which in turn affects the catalytic effect of the photocatalytic material; at the same time, the band gap combination of the binary heterogeneous photocatalytic material constructed by Cu2O and other materials does not cover from ultraviolet to visible light, and the absorption of light is limited. These problems will hinder the photocatalytic efficiency of the photocatalytic material.

[0004] Therefore, it is of great significance to develop a heterostructure that can improve the photocatalytic efficiency of Cu2O. Summary of the invention

[0005] In view of the above problems, one of the objects of the present invention is to provide a heterostructure, which is a Cu2O / Cu / GaON heterostructure formed by compounding Cu2O with Cu and then with GaON. The Cu2O / Cu / GaON heterostructure can enhance the absorption of light and has a suitable energy band structure that is conducive to the effective separation of hole-electron pairs, and its catalytic activity is increased by more than 5 times compared with Cu2O.

[0006] In order to achieve the above object, the present invention can adopt the following technical solutions:

[0007] On one hand, the present invention provides a heterostructure, which includes a Cu2O layer, a Cu layer and a GaON layer, wherein the Cu2O layer is connected to the Cu layer, and the other side of the Cu layer is connected to the GaON layer.

[0008] Another aspect of the present invention provides a method for preparing the above heterostructure, which comprises: growing a Cu layer on a Cu2O layer to form a Cu2O / Cu heterostructure; and then growing GaON on the Cu2O / Cu heterojunction to form a Cu2O / Cu / GaON heterostructure.

[0009] In another aspect, the present invention provides a photoelectric device, which comprises the above-mentioned heterostructure.

[0010] In another aspect, the present invention provides an application of the above-mentioned heterostructure in hydrogen production by photolysis of water.

[0011] The beneficial effects of the present invention include: the heterostructure (Cu2O / Cu / GaON) provided by the present invention increases the transfer of charges, and the Cu intermediate layer greatly increases the light absorption efficiency, and its catalytic activity is greatly increased compared with the Cu2O material, which is increased by more than 5 times, and the photolysis water efficiency is relatively high. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 Schematic diagram of the preparation process of the ternary heterostructure in the present invention;

[0013] Figure 2 This is a scanning electron microscope image of Cu2O thin film material;

[0014] Figure 3 This is the scanning electron microscope image of the Cu2O / Cu heterostructure;

[0015] Figure 4 This is a scanning electron microscope image of the Cu2O / Cu / GaON ternary heterostructure;

[0016] Figure 5 Cu 2 O / Cu / GaON ternary heterojunction photocatalytic water splitting performance test results. DETAILED DESCRIPTION

[0017] The examples are provided to better illustrate the present invention, but the present invention is not limited to the examples. Therefore, those skilled in the art may make non-essential improvements and adjustments to the implementation scheme according to the above invention content, which still fall within the protection scope of the present invention.

[0018] The terms used herein are only used to describe specific embodiments and are not intended to limit the present disclosure. Unless the context has a significantly different meaning, expressions in the singular include expressions in the plural. As used herein, it should be understood that terms such as "include", "have", "include" are intended to indicate the presence of features, numbers, operations, components, parts, elements, materials or combinations. The terms of the present invention are disclosed in the specification, and are not intended to exclude the possibility that one or more other features, numbers, operations, components, parts, elements, materials or combinations thereof may exist or may be added. As used herein, " / " may be interpreted as "and" or "or", depending on the circumstances.

[0019] An embodiment of the present invention provides a heterostructure, which includes a Cu2O layer, a Cu layer and a GaON layer, wherein the Cu2O layer is connected to the Cu layer, and the other side of the Cu layer is connected to the GaON layer.

[0020] It should be noted that the present invention has discovered that the catalytic activity of Cu2O can be improved by compounding Cu2O with Cu and GaON, thereby improving the photoelectrocatalytic efficiency. The catalytic activity of the heterostructure of the present invention is increased by more than 15 times compared with that of Cu2O, and the effect is significant.

[0021] In some specific embodiments, in the above heterostructure, the thickness of the Cu layer can be 0.1 μm-1 μm. It should be noted that the thickness of the Cu layer in the heterostructure can be adjusted to obtain heterostructures with different photolysis water efficiencies. The Cu layer can be obtained by treating the Cu2O layer with NH3 plasma, and its thickness can be precisely controlled by the plasma treatment time, which varies with the presence of the surface pyramid microstructure, generally ranging from 0.1 to 1 micron. In addition, the thickness of the GaON layer can be 40 nanometers.

[0022] In some specific embodiments, the heterostructure further includes a substrate, and the substrate is connected to the Cu2O layer.

[0023] It should be noted that in the heterostructure, a substrate is used as a carrier, and the substrate is a substrate known in the art, such as a FTO substrate.

[0024] Another embodiment of the present invention provides a method for preparing the above-mentioned heterostructure, which includes: growing a Cu layer on a Cu2O layer to form a Cu2O / Cu heterostructure; and then growing GaON on the Cu2O / Cu heterojunction to form a Cu2O / Cu / GaON heterostructure.

[0025] It should be noted that the heterostructure preparation method in the present invention only grows the Cu layer and GaON on the Cu2O layer once, and the preparation method is simple.

[0026] In some specific embodiments, the preparation method further includes: growing a Cu2O layer on a substrate. It should be noted that, as mentioned above, in the heterostructure, a substrate is required as a carrier, so the preparation method further includes growing a Cu2O layer on a substrate, that is, growing a Cu2O layer on a substrate, and then growing a Cu layer on the Cu2O layer to form a Cu2O / Cu heterostructure; and then growing GaON on the Cu2O / Cu heterojunction to form a Cu2O / Cu / GaON heterostructure.

[0027] In some specific embodiments, in the above-mentioned preparation method, the method of growing a Cu layer on a Cu2O layer to form a Cu2O / Cu heterostructure is all methods known in the art, such as using an ammonia plasma method; in addition, the method of growing GaON on a Cu2O / Cu heterostructure to form a Cu2O / Cu / GaON heterostructure is all methods known in the art, such as using a plasma enhanced atomic layer deposition method; furthermore, the method of growing a Cu2O layer on a substrate is a method known in the art, such as an electrochemical deposition method.

[0028] Another embodiment of the present invention provides a photoelectric device, which includes the above heterostructure. It should be noted that the above heterostructure of the present invention can be added with other components to form a photoelectric device.

[0029] Another embodiment of the present invention provides an application of the above-mentioned heterostructure in the production of hydrogen by photolysis of water. It should be noted that the heterostructure in the present invention can be used in the production of hydrogen by photolysis of water, which can enhance the absorption of light and have a suitable energy band structure that is conducive to the effective separation of hole-electron pairs. As a catalyst, it can greatly improve the efficiency of hydrogen production by photolysis of water.

[0030] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with specific examples, but the content of the present invention is not limited to the following examples.

[0031] 1. Preparation and characterization of multilayer heterostructures

[0032] Example 1 Preparation of multilayer heterostructure

[0033] Cu2O material is grown on FTO substrate by electrochemical deposition; the grown Cu2O material is placed in an atomic layer deposition system and treated with ammonia plasma to form a Cu metal layer of a certain thickness on its surface, thereby forming a Cu2O / Cu heterojunction; GaON material is grown on the surface of the Cu2O / Cu heterojunction by plasma enhanced atomic layer deposition, thereby obtaining a Cu2O / Cu / GaON ternary heterostructure.

[0034] Example 2 Characterization of multilayer heterostructures

[0035] The Cu2O material in Example 1 was subjected to scanning electron microscopy. The scanning electron microscopy results are as follows: Figure 2 As shown;

[0036] In addition, the Cu2O / Cu heterojunction in Example 1 was subjected to scanning electron microscopy. Figure 3 As shown; the top layer is a Cu metal layer, and the bottom layer is a Cu2O layer;

[0037] Furthermore, the Cu2O / Cu / GaON ternary heterojunction in Example 1 was subjected to scanning electron microscopy. Figure 4 As shown; the top thin layer is the GaON thin film layer, which is about 40 nanometers thick, the middle layer is the Cu layer, which is 100-1000 nanometers thick, and the bottom layer is the Cu2O layer.

[0038] 2. Electrochemical Test of Multilayer Heterostructure

[0039] Example 3 Photolysis water performance test

[0040] In the present embodiment, the photocatalytic performance of the Cu2O / Cu / GaON ternary heterojunction catalyst prepared in Example 1 was tested. The test results are as follows: Figure 5 The photocatalytic water splitting performance test results of the Cu2O / Cu / GaON ternary heterostructure are compared with the photocatalytic water splitting performance of the Cu2O material. It can be seen from the figure that under the same potential conditions, the photocurrent density of the pure Cu2O material is 0.7mA / cm 2 After adding the Cu layer and the GaON layer, the photocurrent density of the ternary heterojunction is 3.24 mA / cm 2 ; The performance of photolysis of water has been greatly improved.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be covered by the scope of the claims of the present invention.

Claims

1. A heterostructure, characterized in that: It includes a Cu2O layer, a Cu layer and a GaON layer, wherein the Cu2O layer is connected to one side of the Cu layer, and the other side of the Cu layer is connected to the GaON layer.

2. The heterostructure according to claim 1, characterized in that The thickness of the Cu layer is 0.1 μm-1 μm.

3. The heterostructure according to claim 1 or 2, characterized in that: Also included is a substrate, which is connected to the Cu2O layer.

4. The heterostructure according to claim 3, characterized in that: The substrate includes an FTO substrate.

5. The method for preparing a heterostructure according to claim 1, characterized in that: include: A Cu layer is grown on the Cu2O layer to form a Cu2O / Cu heterostructure; and then GaON is grown on the Cu2O / Cu heterostructure to form a Cu2O / Cu / GaON heterostructure.

6. The method for preparing a heterostructure according to claim 3 or 4, characterized in that: include: A Cu2O layer is grown on a substrate; a Cu layer is then grown on the Cu2O layer to form a Cu2O / Cu heterostructure; and GaON is then grown on the Cu2O / Cu heterostructure to form a Cu2O / Cu / GaON heterostructure.

7. The preparation method according to claim 5 or 6, characterized in that: The method of growing a Cu layer on a Cu2O layer to form a Cu2O / Cu heterostructure includes: using an ammonia plasma method for treatment; and / or the method of growing GaON on a Cu2O / Cu heterostructure to form a Cu2O / Cu / GaON heterostructure includes: using a plasma enhanced atomic layer deposition method for treatment.

8. An optoelectronic device, characterized in that A heterostructure comprising any one of claims 1 to 4.

9. Use of the heterostructure according to any one of claims 1 to 4 in hydrogen production by photolysis of water.

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