Gallium nitride-based material photoelectrocatalysis electrode, photoelectrochemical device comprising same and application of gallium nitride-based material photoelectrocatalysis electrode

Abstract

The invention discloses a gallium nitride-based material photoelectrocatalysis electrode, a photoelectrochemical device comprising the same and an application. The photoelectrocatalysis electrode comprises a substrate, a gallium nitride-based material and a gallium nitride-based material, the first type doped gallium nitride-based nanostructure grows on the surface of one side of the substrate, and a reduction catalyst is loaded on the first type doped gallium nitride-based nanostructure and is suitable for promoting reduction reaction under the photoelectric effect; the first-type doped gallium nitride-based nanostructure grows on the surface of one side of the substrate, the second-type doped gallium nitride-based nanostructure grows on the surface of the other side of the substrate, an oxidation catalyst is loaded on the second-type doped gallium nitride-based nanostructure, the first-type doped gallium nitride-based nanostructure is suitable for promoting an oxidation reaction under the photoelectric effect, and the first-type doped gallium nitride-based nanostructure and the second-type doped gallium nitride-based nanostructure are different in type. The photoelectrocatalysis electrode can be used for application scenes of oxidation reaction and reduction reaction at the same time, and catalytic efficiency can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of photoelectrochemical catalytic electrodes, and in particular to a gallium nitride-based photoelectrochemical electrode, a photoelectrochemical device comprising the same, and applications thereof. Background Art

[0002] Photoelectrocatalysis is a technology that uses light energy to drive chemical reactions. It is widely used in water decomposition, hydrogen production, environmental purification and organic synthesis. The key is the design of the working electrode, which plays a decisive role in the catalytic reaction. In photoelectrocatalysis, the working electrode is usually used to promote oxidation and reduction reactions, thereby achieving charge separation and producing the desired chemical reaction.

[0003] Traditional photoelectrocatalytic working electrodes usually have a single function and are often used to promote one type of chemical reaction. This results in limited efficiency and significantly increased costs of photoelectrocatalytic systems, because different electrodes are required for different reactions. In addition, traditional working electrodes also have problems such as poor catalyst dispersion, low reaction efficiency, and low energy conversion efficiency. Summary of the invention

[0004] In view of the above technical problems, the present invention provides a gallium nitride-based photoelectrocatalytic electrode, a photoelectrochemical device comprising the same and applications thereof, in order to at least partially solve at least one of the above-mentioned technical problems.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] As one aspect of the present invention, a gallium nitride-based photoelectrocatalytic electrode is provided, comprising: a substrate; a first-type doped gallium nitride-based nanostructure grown on a surface on one side of the substrate, the first-type doped gallium nitride-based nanostructure being loaded with a reduction catalyst and being suitable for promoting a reduction reaction under the action of photoelectricity; a second-type doped gallium nitride-based nanostructure grown on a surface on the other side of the substrate, the second-type doped gallium nitride-based nanostructure being loaded with an oxidation catalyst and being suitable for promoting an oxidation reaction under the action of photoelectricity, the first-type doping and the second-type doping being of different types.

[0007] In some embodiments of the present invention, the first type of doping includes p-type doping, forming a pn junction, an np junction, a pin junction, or a corresponding tunneling junction structure; the second type of doping includes n-type doping, forming a pn junction, an np junction, or a pin junction; the first type and / or second type doped gallium nitride-based material includes Al x Ga 1-x N、In x Ga 1-x N、In y Alx Ga 1-x-y N.B x Al y Ga 1-x-y N or B x In y Ga 1-x-y N material, wherein 0≤x≤1, 0≤y≤1, x+y≤1, and the polarity of the gallium nitride-based material is metal polarity or nitrogen polarity.

[0008] In some embodiments of the present invention, the gallium nitride-based nanostructure includes any one of a nanocolumn, a planar structure, a triangular pyramid, and any irregular structure. The shape of the nanocolumn is a polygon or any irregular shape, the length of the nanocolumn is 1nm to 10μm, and the width of the nanocolumn is 1nm to 10μm.

[0009] In some embodiments of the present invention, a method for growing a first-type doped or second-type doped gallium nitride-based nanostructure includes: chemical vapor deposition, molecular beam epitaxy, metal organic chemical vapor deposition, hydrothermal method or magnetron sputtering.

[0010] In some embodiments of the present invention, the reduction catalyst includes precious metal particles and transition metal particles; the precious metal particles include: platinum, gold, iridium, silver or rhodium; the transition metal particles include: iron, cobalt or nickel; the oxidation catalyst includes metal oxides and transition metal sulfides; the metal oxides include ruthenium oxide, iridium oxide, cobalt oxide or copper oxide; the transition metal sulfides include cobalt sulfide, iron sulfide, nickel sulfide.

[0011] In some embodiments of the present invention, the photoelectrocatalytic electrode further comprises: an electrode layer, which forms an ohmic contact with a portion of the substrate where the gallium nitride-based nanostructure is not formed, and is configured to contact a metal wire for current conduction.

[0012] In some embodiments of the present invention, the method of supporting the reduction / oxidation catalyst includes: photodeposition, electrodeposition, photoelectric deposition, magnetron sputtering or impregnation.

[0013] In some embodiments of the present invention, the substrate is a conductive substrate.

[0014] As another aspect of the present invention, a photoelectrochemical device is also provided, comprising the gallium nitride-based photoelectrocatalytic electrode as described above.

[0015] As another aspect of the present invention, there is also provided an application of the above-mentioned photoelectrochemical device in photoelectric, electrical or photocatalytic reactions of water decomposition, CO2 reduction, nitrogen reduction, organic matter decomposition, organic matter oxidation, and seawater chlorine absorption.

[0016] Based on the above technical solution, the gallium nitride-based photoelectrocatalytic electrode, the photoelectrochemical device containing the same and the application of the present invention have at least one or part of the following beneficial effects:

[0017] The present invention grows first-type doped gallium nitride-based nanostructures and second-type doped gallium nitride-based nanostructures with different doping types on two surfaces of a substrate respectively, and loads a reduction catalyst on the first-type doped gallium nitride-based nanostructure; loads an oxidation catalyst on the second-type doped gallium nitride-based nanostructure, and directionally loads the catalyst on the first-type doped and second-type doped gallium nitride-based nanostructures, so that the obtained photoelectric catalytic electrode can be used for oxidation reaction and reduction reaction respectively without changing the light source conditions, realizing the design of a dual-functional working electrode, so that the obtained photoelectric catalytic electrode can be used for different types of photoelectric catalytic reactions at the same time, improving the catalytic efficiency and saving the cost of making multiple different types of catalytic electrodes. In addition, by loading different oxidation or reduction catalysts, the dispersibility and catalytic efficiency of the oxidation or reduction catalyst are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A growth variation diagram of the first-type and second-type doped gallium nitride-based nanostructures according to an embodiment of the present invention;

[0019] Figure 2 A diagram showing the change process of the catalyst loaded on the first-type and second-type doped gallium nitride-based nanostructures according to an embodiment of the present invention;

[0020] Figure 3 is a schematic diagram of the surface structure of an electrode layer according to an embodiment of the present invention;

[0021] Figure 4 A schematic diagram of a three-electrode photoelectrochemical device according to an embodiment of the present invention;

[0022] Figure 5 A flowchart of the construction of a three-electrode photoelectrochemical device according to an embodiment of the present invention;

[0023] Figure 6 The RuO loaded on the n-type doped InGaN nanowire of Example 1 of the present invention x A current density variation curve of

[0024] Figure 7 This is a curve diagram of current density variation when Pt is loaded on a p-type doped InGaN nanowire according to Example 1 of the present invention.

[0025] [Description of Reference Numerals]

[0026] 1- substrate;

[0027] 2- Type I doped GaN-based nanostructures;

[0028] 3- Type II doped GaN-based nanostructures;

[0029] 4-reduction catalyst;

[0030] 5-oxidation catalyst;

[0031] 6- Conductive metal;

[0032] 7- Epoxy resin;

[0033] 8-p / n-type doped GaN nanowires;

[0034] 9- light-transmitting container;

[0035] 10-GaN-based photoelectrocatalytic electrode;

[0036] 11- reference electrode;

[0037] 12- counter electrode;

[0038] 13- Power controller. DETAILED DESCRIPTION

[0039] For example, in the related art, indium tin oxide or titanium dioxide is usually used to promote specific oxidation or reduction reactions, and cannot be used for multiple types of photoelectrocatalytic reactions at the same time, which limits the versatility and efficiency of the reaction system and increases the cost. And due to the uniform loading of the catalyst, the catalytic activity and dispersibility of these working electrodes are relatively poor. In the process of realizing the present invention, it is found that the first type and / or second type doped gallium nitride-based nanostructures are grown on both sides of the substrate, and the reduction catalyst is loaded on the first type doped gallium nitride-based nanostructure, and the oxidation catalyst is loaded on the second type doped gallium nitride-based nanostructure. It can promote the reduction reaction and oxidation reaction respectively under the action of photoelectricity, which can improve the catalytic efficiency and reduce the preparation cost.

[0040] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0041] But it should be understood that these descriptions are exemplary only, and are not intended to limit the scope of the present invention. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of embodiments of the present invention. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, the description of known techniques is omitted to avoid unnecessary confusion of concepts of the present invention.

[0042] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The term "comprising" used herein indicates the existence of features, steps, operations, but does not exclude the existence or addition of one or more other features.

[0043] In the case of using expressions such as "at least one of A, B, and C, etc.", it should generally be interpreted in accordance with the meaning of the expression generally understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.). In the case of using expressions such as "at least one of A, B, or C, etc.", it should generally be interpreted in accordance with the meaning of the expression generally understood by those skilled in the art (for example, "a system having at least one of A, B, or C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0044] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0045] Figure 1 is a growth variation diagram of the first-type and second-type doped gallium nitride-based nanostructures according to an embodiment of the present invention, Figure 2 This is a diagram showing the change process of the catalyst loaded on the first type and second type doped gallium nitride-based nanostructures according to an embodiment of the present invention.

[0046] The embodiment of the present invention provides a gallium nitride-based photoelectrocatalytic electrode, such as Figure 1 and Figure 2 As shown, it includes a substrate 1, a first-type doped gallium nitride-based nanostructure 2, a second-type doped gallium nitride-based nanostructure 3, a reduction catalyst 4 and an oxidation catalyst 5. The substrate 1 is used as a base for growing nanostructures, and its lattice structure directly affects the growth quality and growth orientation of the nanostructure. The first-type doped gallium nitride-based nanostructure 2 grows on the surface of one side of the substrate 1, and the first-type doped gallium nitride-based nanostructure 2 is loaded with a reduction catalyst 4, which is suitable for promoting the occurrence of a reduction reaction under the action of photoelectricity. The second-type doped gallium nitride-based nanostructure 3 grows on the surface of the other side of the substrate 1, and the second-type doped gallium nitride-based nanostructure 3 is loaded with an oxidation catalyst 5, which is suitable for promoting the occurrence of an oxidation reaction under the action of photoelectricity, wherein the first-type doping and the second-type doping are different in type.

[0047] In some embodiments of the present invention, by growing the first-type doped gallium nitride-based nanostructure 2 and the second-type doped gallium nitride-based nanostructure 3 with different doping types on the two surfaces of the substrate 1, and loading the reduction catalyst 4 on the first-type doped gallium nitride-based nanostructure 2; loading the oxidation catalyst 5 on the second-type doped gallium nitride-based nanostructure 3, the catalyst is loaded on the first-type doped or second-type doped gallium nitride-based nanostructure in a directional manner, and because the types of the first-type doping and the second-type doping are different, the obtained photoelectrocatalytic electrode 10 can be used for oxidation reaction and reduction reaction respectively without changing the light source conditions, realizing the design of a dual-functional working electrode, so that the obtained photoelectrocatalytic electrode 10 can be used for different types of photoelectrocatalytic reactions, simplifying the structure of the photoelectrocatalytic electrode, improving the catalytic efficiency and saving the cost of making multiple different types of catalytic electrodes. In addition, by loading different oxidation or reduction catalysts, the dispersibility and catalytic efficiency of the oxidation or reduction catalysts are improved.

[0048] In some embodiments of the present invention, the first type of doping includes p-type doping, forming a pn junction, an np junction, a pin junction, or a corresponding tunneling junction structure; the second type of doping includes: n-type doping, forming a pn junction, an np junction, or a pin junction. For example, the first type of doping may be p-type doping, and the second type of doping may be n-type doping. The first type of doping and the second type of doping are used to introduce additional electrons or holes into gallium nitride, thereby changing the conductive properties of gallium nitride. Among them, n-type doping is to introduce additional electrons into gallium nitride, and these introduced electrons become carriers in gallium nitride, so that n-type doped gallium nitride has a higher electron concentration and conductive properties. P-type doping is to introduce additional holes into gallium nitride, that is, positive charges, and these introduced holes become carriers in gallium nitride, so that p-type doped gallium nitride has a higher hole concentration and conductive properties. In addition, n-type doping causes an oxidation reaction on the surface of the nanostructure, which can be applied to a photoanode; p-type doping causes a reduction reaction on the surface of the nanostructure, which can be applied to a photocathode. The pn junction and np junction are structures formed by the contact between the n-type doped region and the p-type doped region. The pin junction introduces the structure of the i-type layer in gallium nitride. The i-type layer is a neutral layer, that is, an undoped or lightly doped semiconductor i-type layer is added between the pn junction. This structure can reduce the recombination loss of charge carriers and improve the catalytic performance of the photoelectric catalytic electrode. The tunneling junction is a special structure that contains a very thin dielectric layer. The tunneling junction can effectively prevent the mutual migration of p-end and n-end carriers, and promote tunneling recombination, which is beneficial for the p-end electrons to migrate into the solution to obtain a larger photocurrent.

[0049] In some embodiments of the present invention, the gallium nitride-based nanostructure includes any one of a nanocolumn, a planar structure, a triangular pyramid, and any irregular structure. The shape of the nanocolumn is a polygon or any irregular shape, the length of the nanocolumn is 1nm to 10μm, and the width of the nanocolumn is 1nm to 10μm. As described above, different nanostructures provide the function of increasing the surface area of ​​the gallium nitride-based nanostructure and providing a carrier transmission path, thereby adjusting and optimizing the electrical and optical properties of gallium nitride. When the gallium nitride-based nanostructure is a nanowire structure, the first-type doped gallium nitride-based nanostructure 2 and the second-type doped gallium nitride-based nanostructure 3 grow vertically to the substrate 1, respectively. The nanocolumn structure is a three-dimensional nanostructure composed of columnar structures of different sizes, and the length of the columnar structure is 1nm to 10μm and the width is 1nm to 10μm.

[0050] In some embodiments of the present invention, the method of growing a first-type doped or second-type doped gallium nitride-based nanostructure includes: chemical vapor deposition, molecular beam epitaxy, metal organic chemical vapor deposition, hydrothermal method or magnetron sputtering, preferably molecular beam epitaxy. Specifically, the chemical vapor deposition method transports gaseous precursor molecules, usually metal organic compounds and ammonia, to a substrate for chemical reaction to form a gallium nitride nanostructure. Molecular beam epitaxy (MBE) is a method of growing gallium nitride-based nanostructures by evaporating or depositing atoms or molecules layer by layer, by heating the epitaxial source under vacuum conditions to evaporate or sputter metal organic precursor molecules and nitrogen source molecules, so that they are deposited on the substrate, thereby forming a gallium nitride-based nanostructure. Metal organic chemical vapor deposition reacts metal organic precursor molecules with gaseous carrier gas molecules on the substrate to deposit gallium nitride-based nanostructures. The hydrothermal method grows gallium nitride-based nanostructures by chemically reacting in an aqueous solution at a relatively high temperature and pressure. Magnetron sputtering is a method of physical vapor deposition that accelerates ions in an atmosphere to sputter atoms on gallium nitride to form gallium nitride-based nanostructures.

[0051] In some embodiments of the present invention, the reduction catalyst includes a noble metal or a transition metal. The noble metal includes platinum, gold, iridium, silver or rhodium. The transition metal includes iron, cobalt or nickel. The oxidation catalyst includes a metal oxide or a transition metal sulfide. The metal oxide includes ruthenium oxide, iridium oxide, cobalt oxide or copper oxide. The transition metal sulfide includes cobalt sulfide, iron sulfide and nickel sulfide. The reduction catalyst and / or oxidation catalyst are nanoparticles grown on the surface of the gallium nitride-based nanostructure in order to promote the redox reaction, which can promote the separation of photogenerated electrons and holes in the gallium nitride-based nanostructure and optimize the adsorption and desorption process of the chemical products generated by the oxidation reaction and / or reduction reaction.

[0052] In some embodiments of the present invention, the gallium nitride-based photoelectrocatalytic electrode further includes: an electrode layer, which forms an ohmic contact with a portion of the substrate 1 where the gallium nitride-based nanostructure is not formed, and is configured to contact a metal wire for current conduction. Figure 3 Schematic diagram of the surface structure of the electrode layer of an embodiment of the present invention, Figure 3 As shown, specifically, after growing p / n-type doped gallium nitride nanowires 8 on both sides of the silicon substrate, a portion of the gallium nitride nanowires is scraped off for contact with the conductive metal 6. Since the silicon substrate is in direct contact with the conductive metal 6 to form a Schottky barrier, it is not conducive to current conduction. Therefore, the gallium nitride nanowires are scraped off to expose the silicon substrate portion and a liquid gallium-indium alloy is applied to form an ohmic contact, thereby realizing the preparation of the electrode layer. Then, silver glue is applied to the copper metal strip, and it is compacted with the silicon substrate surface coated with the liquid gallium-indium alloy. Finally, the electrode is encapsulated with epoxy resin 7, leaving only the growth surface of the p / n-type doped gallium nitride nanowire 8 exposed.

[0053] In some embodiments of the present invention, the method of loading the reduction / oxidation catalyst includes: photodeposition, electrodeposition, photoelectric deposition, magnetron sputtering or impregnation. The photodeposition method converts the catalyst precursor molecules into active substances through photoexcitation, and deposits them on the surface of the gallium nitride-based nanostructure to form a reduction / oxidation catalyst. The electrodeposition method uses an external potential to apply voltage to the gallium nitride-based nanostructure to reduce the catalyst ions to metals or oxides, thereby achieving the loading of the reduction / oxidation catalyst. The photoelectric deposition method combines the characteristics of photochemistry and electrochemistry. Under the action of the external potential and light, the catalyst precursor molecules undergo a reduction reaction on the surface of the gallium nitride-based nanostructure to form a reduction / oxidation catalyst deposition. Magnetron sputtering generates an ion beam on the surface of the target material, so that the catalyst precursor material is released and deposited on the gallium nitride-based nanostructure. The impregnation method dissolves or suspends the catalyst precursor in a solvent, and immerses the gallium nitride-based nanostructure in the solution, so that the reduction / oxidation catalyst enters the pores of the gallium nitride-based nanostructure by adsorption or chemical reaction.

[0054] In some embodiments of the present invention, the substrate is a conductive substrate, including: a silicon substrate, a metal substrate, a nitride single crystal or an organic flexible substrate, preferably a silicon substrate. The silicon substrate has good mechanical stability and electrical properties. In the photoelectric catalytic electrode, the silicon substrate can serve as a platform for supporting and stabilizing the reduction / oxidation catalyst. The silicon substrate can provide a sufficient smooth surface area so that the gallium nitride-based nanostructure and the reduction / oxidation catalyst can be distributed more evenly on the surface of the silicon substrate. By using the above substrate, an electron transmission path can be provided, the light absorption performance and transmittance can be improved, and the active surface area can be increased.

[0055] In some embodiments of the present invention, the gallium nitride-based material based on the first type and / or second type doping includes Al x Ga1-x N、In x Ga 1-x N、In y Al x Ga 1-x-y N.B x Al y Ga 1-x-y N or B x In y Ga 1-x-y N material, wherein 0≤x≤1, x can be, for example, 0, 0.3, 0.5, 0.7 or 1, 0≤y≤1, y can be, for example, 0, 0.3, 0.5, 0.7 or 1, but is not limited thereto, and x+y≤1, the polarity of the gallium nitride-based material is metal polarity or nitrogen polarity. The gallium nitride-based material as described above has metal polarity or nitrogen polarity, and therefore has adjustable optical and electrical properties, is suitable for photoelectrocatalytic electrodes, and by adjusting the values ​​of x and y, the desired gallium nitride-based material performance can be achieved.

[0056] As another aspect of the present invention, a photoelectrochemical device is also provided, comprising the gallium nitride-based photoelectrocatalytic electrode as described above.

[0057] Figure 4 Schematic diagram of a three-electrode photoelectrochemical device according to an embodiment of the present invention.

[0058] Please refer to Figure 4 , including: a light-transmitting container 9, the gallium nitride-based photoelectrocatalytic electrode 10 as described above, a reference electrode 11, a counter electrode 12 and a power controller 13. The light-transmitting container 9 is used to contain an electrolyte solution. The gallium nitride-based photoelectrocatalytic electrode 10 as described above is arranged in the light-transmitting container 9, and is suitable for promoting the occurrence of reduction reaction and oxidation reaction respectively under the action of photoelectric. The power controller 13 is electrically connected to the gallium nitride-based photoelectrocatalytic electrode 10, the reference electrode 11 and the counter electrode 12, and is suitable for providing electron flow to the gallium nitride-based photoelectrocatalytic electrode 10 and the counter electrode 12.

[0059] In some embodiments of the present invention, the photoelectrochemical device of the present invention can be applied to both the photoanode and the photocathode, which greatly simplifies the configuration of the photoelectrocatalytic device, improves the energy conversion efficiency and significantly reduces the cost of the photoelectrocatalytic device.

[0060] In some embodiments of the present invention, specifically, taking a three-electrode photoelectrochemical device as an example, Figure 4As shown, an electrolyte solution is added to a light-transmitting container 9, and a 0.5 mol / L sulfuric acid solution is selected as the electrolyte solution. Then, the gallium nitride-based photoelectrocatalytic electrode 10 prepared as described above, the reference electrode 11, using silver or silver chloride as the reference electrode 11, and the counter electrode 12, using a Pt mesh electrode, are placed in the sulfuric acid solution, and the conductive end is connected to the power controller 13. The test parameters of the power controller 13 are set by a computer, and the device is completed.

[0061] An embodiment of the present invention also provides an application of the above-described photoelectrochemical device in photoelectric, electrical or photocatalytic reactions of water decomposition, CO2 reduction, nitrogen reduction, organic matter decomposition, organic matter oxidation, and seawater chlorine absorption.

[0062] In some embodiments of the present invention, the photoelectrochemical device of the present invention can be applied to both the photoanode and the photocathode, thereby providing new possibilities for photoelectrocatalytic applications, overcoming the drawbacks of traditional working electrodes, and is expected to solve the problems existing in traditional working electrodes, while simplifying the preparation process and saving costs.

[0063] Figure 5 The flowchart of the photoelectrochemical device of the embodiment of the present invention is as follows: Figure 5 As shown, the construction process includes steps S501 to S504.

[0064] In S501 , a first-type gallium nitride-based nanostructure 2 and a second-type gallium nitride-based nanostructure 3 are grown on two surfaces of a substrate 1 , respectively.

[0065] In S502 , a reduction catalyst 4 is supported on the first-type gallium nitride-based nanostructure 2 , and an oxidation catalyst 5 is supported on the second-type gallium nitride-based nanostructure 2 .

[0066] In S503, the substrate 1 on both sides of which the oxidation / reduction catalyst has been loaded is packaged accordingly to prepare a photoelectrocatalytic electrode.

[0067] At S504, a photoelectrochemical device is constructed.

[0068] Continue to combine Figure 1 to Figure 4 As shown, the preparation process of the photoelectrochemical device provided by the present invention is relatively simple, and the obtained photoelectrochemical device has a relatively broad application prospect.

[0069] The following lists a number of specific embodiments to illustrate the technical solution of the present invention in detail. It should be noted that the specific embodiments below are only used for illustration and are not used to limit the present invention.

[0070] Example 1

[0071] The preparation process of the gallium nitride-based photoelectrocatalytic electrode includes:

[0072] Prepare an n-type silicon substrate, use trimethylgallium, trimethylindium, and ammonia as growth precursors to provide gallium source, indium source, and nitrogen source, where the equivalent pressure of the gallium source is 5×10 -8 torr, the equivalent pressure of the indium source is 4×10 -8 torr, and the forward plasma power is 350 W. Silicon is used as the doping source for n-type InGaN, magnesium is used as the doping source for p-type InGaN, and hydrogen is used as the carrier gas to grow n-type InGaN nanowires and p-type InGaN nanowires on the front and back sides of the silicon substrate, respectively.

[0073] RuO was deposited by photoelectrochemical deposition. x The photoelectrodeposition adopts a three-electrode structure, the electrolyte is 40ml of 0.2M RuCl3 solution, and the xenon lamp is used as the light source with a light intensity of 100mW / cm 2 , the n-type InGaN nanowires were exposed to light and operated in the current-time mode for 10 minutes. Then the electrolyte was replaced with 40 ml of 0.2 M H2PtCl6, the p-type InGaN nanowires were exposed to light, operated in the current-time mode for 10 minutes, then taken out and washed with distilled water. Finally, the oxidation catalyst RuO was loaded on the n-type InGaN nanowires. x , used for photoanode catalysis. The reduction catalyst Pt is loaded on the p-type InGaN nanowire for photocathode catalysis to obtain the InGaN bifunctional photoelectrocatalytic electrode.

[0074] The use intensity is 100mW / cm 2 A xenon lamp was used as the light source, 0.5 mol / L sulfuric acid solution was added to the light-transmitting container, the InGaN photoelectric catalytic electrode, silver reference electrode, and Pt mesh counter electrode were placed in the sulfuric acid solution, the conductive ends were connected to the power controller, and the InGaN photoelectric catalytic device was completed.

[0075] The oxidation performance of the InGaN photoelectric catalytic device was tested. Figure 6 The RuO loaded on the n-type doped InGaN nanowire of Example 1 of the present invention x The current density variation curve of NWs is shown in Figure 2, where NWs represents nanowire structure. Figure 6 As shown in the figure, when the InGaN photocatalytic electrode is used as a photoanode, the n-type InGaN nanowire can reach 10.86 mA / cm 2 The current density of InGaN is 2.4 Å, which proves the ability of InGaN to be used in photoanode.

[0076] The reduction performance of the InGaN photoelectric catalytic device was tested. Figure 71 is a graph showing the current density variation of the p-type doped InGaN nanowire loaded with Pt according to Example 1 of the present invention. Figure 7 As shown, when the InGaN photocatalytic electrode is used as a photocathode, the p-type InGaN nanowires exhibit good hydrogen evolution performance under light irradiation, proving the ability of applying the InGaN photocatalytic electrode to the photocathode.

[0077] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A gallium nitride-based photoelectrocatalytic electrode, comprising: substrate; A first-type doped gallium nitride-based nanostructure is grown on a surface of one side of the substrate, and a reduction catalyst is loaded on the first-type doped gallium nitride-based nanostructure, which is suitable for promoting a reduction reaction under the action of photoelectricity; A second-type doped gallium nitride-based nanostructure is grown on the surface of the other side of the substrate. An oxidation catalyst is loaded on the second-type doped gallium nitride-based nanostructure, which is suitable for promoting an oxidation reaction under the action of photoelectricity, wherein the first-type doping and the second-type doping are of different types.

2. The gallium nitride-based photoelectrocatalytic electrode according to claim 1, wherein: The first type of doping includes p-type doping, forming a pn junction, an np junction, a pin junction or a corresponding tunneling junction structure; the second type of doping includes n-type doping, forming a pn junction, an np junction or a pin junction; The first type and / or second type doped gallium nitride based materials include Al x Ga 1-x N、In x Ga 1-x N、In y Al x Ga 1-x-y N.B x Al y Ga 1-x-y N or B x In y Ga 1-x-y N material, wherein 0≤x≤1, 0≤y≤1, x+y≤1, and the polarity of the gallium nitride-based material is metal polarity or nitrogen polarity.

3. The gallium nitride-based photoelectrocatalytic electrode according to claim 1, wherein: The gallium nitride-based nanostructure includes any one of a nanocolumn, a planar structure, a triangular pyramid and any irregular structure, wherein the shape of the nanocolumn is a polygon or any irregular shape, the length of the nanocolumn is 1nm to 10μm, and the width of the nanocolumn is 1nm to 10μm.

4. The gallium nitride-based photoelectrocatalytic electrode according to claim 1, wherein: Methods for growing first-type doped or second-type doped gallium nitride-based nanostructures include chemical vapor deposition, molecular beam epitaxy, metal organic chemical vapor deposition, hydrothermal method or magnetron sputtering.

5. The gallium nitride-based photoelectrocatalytic electrode according to claim 1, wherein: The reduction catalyst includes precious metal particles and transition metal particles; the precious metal particles include platinum, gold, iridium, silver or rhodium; the transition metal particles include iron, cobalt or nickel; The oxidation catalyst includes metal oxides and transition metal sulfides; the metal oxide includes ruthenium oxide, iridium oxide, cobalt oxide or copper oxide; the transition metal sulfides include cobalt sulfide, iron sulfide and nickel sulfide.

6. The gallium nitride-based photoelectrocatalytic electrode according to claim 1, further comprising: The electrode layer forms an ohmic contact with a portion of the substrate where no gallium nitride-based nanostructure is formed, and is configured to contact a metal wire for current conduction.

7. The gallium nitride-based photoelectrocatalytic electrode according to claim 1, wherein: Methods for supporting the reduction / oxidation catalyst include: photodeposition, electrodeposition, photoelectrodeposition, magnetron sputtering or impregnation.

8. The gallium nitride-based photoelectrocatalytic electrode according to claim 1, wherein: The substrate is a conductive substrate.

9. A photoelectrochemical device, comprising the gallium nitride-based photoelectrocatalytic electrode according to any one of claims 1 to 8.

10. An application of the photoelectrochemical device as claimed in claim 9 in photoelectric, electrical or photocatalytic reactions of water decomposition, CO2 reduction, nitrogen reduction, organic matter decomposition, organic matter oxidation, and seawater chlorine absorption.

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