Blackbody gold / cuprous oxide heterostructure nano-photocatalytic material with different morphologies, and preparation method and application thereof

Abstract

The present application relates to a kind of black body gold / cuprous oxide heterostructure nanomaterial and its preparation method, belong to nanomaterial and photocatalysis field.The present application is in solution phase, first by ligand modification black body gold nanoparticles, then induce cuprous oxide directional growth on its surface, construct black body gold / cuprous oxide hybrid nanoparticles.By adjusting reaction condition, can realize from the core-shell structure of the complete coating of black body gold seed with cuprous oxide, to the island growth of cuprous oxide on the Janus semi-coated structure of black body gold on the surface of black body gold.The obtained heterostructure has the advantages of uniform structure, good repeatability, and the size and loading number of cuprous oxide crystal can be flexibly controlled.The heterostructure can be directly used for photocatalytic CO2 reduction reaction, and the Janus structure shows excellent reduction efficiency in the generation of C2 product ethane, providing a new material system for solar energy conversion and artificial carbon cycle.

Description

Technical Field

[0001] This invention relates to a method for preparing composite nanomaterials with heterostructures by further modifying the surface energy of blackbody gold nanoparticles based on ligand synthesis and by growing semiconductor cuprous oxide in situ on the surface of the blackbody gold nanoparticles with thiol ligands, and belonging to the technical field of nanomaterial preparation. Background Technology

[0002] Photocatalysis is an alternative to solar cells, enabling the direct utilization of clean and sustainable solar energy. Due to its strong redox capabilities and environmentally friendly characteristics, photocatalysis shows great potential in solving energy and environmental problems. However, photocatalytic materials face challenges in solar energy utilization efficiency and the generation of photoelectrons (e...). - ) and holes (h + Its low efficiency in separation and transmission severely restricts its practical application in various fields.

[0003] To address these issues, various strategies have been employed to compensate for these shortcomings. For example, introducing vacancy defects and doping with metallic or non-metallic impurities into semiconductors can effectively narrow the band gap, enhance light absorption, accelerate electron-hole separation, and suppress their recombination. Furthermore, constructing semiconductor-based hybrid structures can generate synergistic effects, thereby significantly optimizing light absorption and enhancing charge separation efficiency.

[0004] Although photocatalytic degradation of organic pollutants has been extensively studied, photocatalytic carbon dioxide reduction (CO2RR) is a more challenging and far-reaching process. Unlike pollutant degradation, which is typically a thermodynamically favorable reaction driven by strong oxidizing free radicals, CO2 reduction requires the activation of a highly stable linear molecule with a C=O bond energy as high as approximately 750 kJ / mol. -1 The chemical inertness of CO2 leads to slow reaction kinetics, and it also involves multiple electron transfers and complex proton coupling reaction pathways. Therefore, achieving efficient CO2 conversion requires precise control over light absorption capacity, charge separation efficiency, and surface catalytic sites.

[0005] Furthermore, while photocatalytic degradation primarily removes pollutants, it cannot store solar energy. In contrast, CO2 reduction can directly convert greenhouse gases into value-added chemicals and solar fuels, such as CO, CH4, and C2 hydrocarbons. This process is similar to natural photosynthesis, providing a potential pathway for constructing artificial carbon cycles and producing renewable fuels, thereby simultaneously serving energy storage needs.

[0006] On the other hand, CO2 reduction involves selective multi-electron transfer processes (CO requires 2 electrons, CH4 requires 8 electrons, while C2 products typically require ≥12 electrons), making product selectivity a core challenge that distinguishes it from degradation reactions. Simultaneously, competition from the hydrogen evolution reaction (HER) further increases the system complexity, necessitating the use of rational catalyst design to regulate reaction intermediates and interfacial charge kinetics. Therefore, developing highly efficient photocatalytic CO2 reduction catalysts is not only a significant scientific challenge in catalysis and materials chemistry but also a crucial step in realizing solar energy-to-fuel conversion technologies.

[0007] Despite some progress in catalyst development for photocatalytic CO2 reduction technology, challenges remain, including low catalytic efficiency, poor selectivity, and insufficient energy conversion efficiency. According to the applicant, current photocatalysts mainly suffer from low active site density, poor photogenerated carrier separation efficiency, and slow reaction kinetics, which limit the further development and application of the technology. Therefore, developing efficient, stable photocatalysts that can operate under visible light, especially materials that can effectively optimize electronic structure, increase active site density, and improve electron-hole separation efficiency, remains a core research challenge. Summary of the Invention

[0008] The technical problem solved by this invention is to provide a method for preparing blackbody gold / cuprous oxide heterostructure nanomaterials based on solution-phase seed growth. This structure achieves a typical Mott-Schottky junction between the metal and semiconductor components, with spatial physical separation between the components, allowing for full exposure of the surfaces of both materials. This effectively overcomes the low light absorption efficiency of traditional hybrid materials and the charge accumulation problem common in core-shell structures. The resulting blackbody gold / cuprous oxide heterostructure nanomaterials can be directly used for photocatalytic CO2 reduction testing. Compared with core-shell structured nanoparticles, the blackbody gold / cuprous oxide heterostructure material of this invention exhibits superior reduction efficiency of C2 products (ethane), showing excellent prospects for photocatalytic applications. Compared with photocatalytic degradation reactions, photocatalytic CO2 reduction is inherently more challenging due to the need to activate chemically inert CO2 molecules and achieve selective multi-electron proton coupling transfer processes, but it also provides a direct pathway for solar fuel production and artificial carbon cycling.

[0009] This invention first modifies the surface energy of gold nanoparticles with a chiral aliphatic thiol ligand, L-cysteine, inducing preferential growth of gold along specific crystal planes to obtain blackbody gold nanoparticles with a dendritic structure. This structure exhibits excellent broad-spectrum light absorption and a highly rough surface morphology, providing an ideal platform for subsequent heteroepitaxial construction. Subsequently, the blackbody gold nanoparticles are further modified with 5-amino-2-mercaptobenzimidazole (AMBI). By controlling the amount of AMBI added, the local surface energy of the gold surface is precisely adjusted, achieving selective heteroepitaxial growth of cuprous oxide. This leads to the construction of a series of blackbody gold / cuprous oxide heterostructure nanomaterials with different interface structures, including core-shell structures and continuously tunable Janus structures. Through precise control of the AMBI ligand dosage, the morphology and structure can be gradually adjusted, thereby endowing the materials with tunable photoelectrocatalytic properties.

[0010] To address the aforementioned technical problems, the present invention proposes the following technical solution: A solution-phase synthesis route is employed, using dendritic blackbody gold nanoparticles as seed materials. The heterostructure is controllably constructed by regulating the interfacial ligands and reaction conditions. First, different amounts of the strong ligand AMBI are introduced into an aqueous solution system of the blackbody gold nanoparticles. An incubation method is used to ensure its full adsorption onto the surface of the gold nanoparticles, thereby controlling the interfacial energy. Subsequently, the surfactant sodium dodecyl sulfate (SDS), the cuprous oxide precursor copper chloride (CuCl2), the precipitant sodium hydroxide (NaOH), and the reducing agent hydroxylamine hydrochloride (NH2OH·HCl) are added to the system to form a reaction mixture. After a certain period of static reaction, island-shaped cuprous oxide is directionally grown on the surface of the blackbody gold nanoparticles, forming a blackbody gold / cuprous oxide hybrid nanomaterial with a heterostructure.

[0011] Preferably, a method for preparing a multi-morphological blackbody gold / cuprous oxide heterostructure nanophotocatalytic material is provided, which can be carried out sequentially according to the following steps:

[0012] (1) Gold nanospheres with a particle size of 60 nm were synthesized according to the seed growth method in the literature (J. Am. Chem. Soc. 2012, 134, 4, 2004-2007). The final product was centrifuged at 6000 rpm for 15 min to remove the supernatant. The centrifugation was repeated once to remove the excess surfactant sodium citrate. The resulting precipitate was redispersed in an equal volume of deionized water.

[0013] (2) 1.5 mL of cetyltrimethylammonium bromide (CTAB) solution (100 mM), 0.5 mL of chloroauric acid trihydrate (HAuCl4·3H2O) solution (50 mM), 0.5 mL of ascorbic acid (AA) solution (100 mM), 0.5 mL of L-cysteine ​​solution (10 mM), 1 mL of gold nanospheres synthesized in step (1) and 8 mL of deionized water were added to the reaction system in sequence, mixed evenly, and reacted at room temperature for 20 min to prepare black black body gold nanoparticles with dendritic structure;

[0014] (3) The synthesized blackbody gold nanoparticles were centrifuged at 6000 rpm for 15 min to remove the supernatant, and centrifuged twice to remove excess surfactant CTAB (hexadecyltrimethylammonium bromide), and then dispersed in the same volume of water.

[0015] (4) Under high-speed vortex oscillation, the 1 mL volume of blackbody gold nanoparticles obtained above was mixed with different volumes of thiol ligand 5-amino-2-mercaptobenzimidazole (AMBI) solution (10 mM), and the mixture was incubated in a 60℃ oven for 2 h before being cooled to room temperature.

[0016] (5) Under high-speed vortex oscillation, add 9.45 mL H2O, 87 mg SDS, 0.6 mL CuCl2 solution of different concentrations, the solution from step (4), 0.25 mL NaOH solution (1 M) and 0.1 mL reducing agent NH2OH·HCl solution (200 mM) to a 20 mL reaction flask in sequence. After standing at room temperature for 20 min, a series of blackbody gold / cuprous oxide heterostructure nanophotocatalytic materials can be obtained.

[0017] Preferably, the diameter of the gold sphere used in step (1) can be 10 to 100 nm.

[0018] Preferably, the molar ratio of L-cysteine ​​solution to reducing agent ascorbic acid used in step (2) is in the range of 1 to 5: 10000.

[0019] Preferably, the amount of thiol ligand AMBI (10 mM) used in step (4) is in the range of 1 μL to 15 μL.

[0020] Preferably, the concentration range of 0.5 mL of copper chloride in step (5) is 2 mM to 30 mM.

[0021] Preferably, the molar ratio of the cuprous oxide precursor solution to the sodium hydroxide solution in step (5) is 3 to 10:650.

[0022] Preferred: Includes the following steps:

[0023] (1) Preparation of gold nanospheres: Gold nanospheres with a particle size of about 60 nm were centrifuged at 6000 rpm for 15 min, the supernatant was removed, and the centrifugation was repeated once to remove excess surfactant sodium citrate. The resulting precipitate was redispersed in an equal volume of deionized water.

[0024] (2) Synthesis of blackbody gold nanoparticles: Under high-speed vortex oscillation conditions, the following components were added to the reaction vessel in sequence: 1.5 mL CTAB (100 mM), 0.5 mL HAuCl4 (50 mM), 0.5 mL AA (100 mM), 0.5 mL L-cysteine ​​(10 mM), 8 mL deionized water and 1 mL of the gold ball dispersion prepared in step (1). After mixing, the mixture was reacted at room temperature for 15 min to obtain blackbody gold nanoparticles with a dendritic structure.

[0025] (3) The synthesized blackbody gold nanoparticles were centrifuged at 6000 rpm for 15 min to remove the supernatant, and centrifuged twice to remove excess surfactant CTAB (hexadecyltrimethylammonium bromide), and then dispersed in the same volume of water.

[0026] (4) Under high-speed vortex oscillation, 10 μL of the thiol ligand AMBI (10 mM) was injected into 1 mL of the blackbody gold nanomaterial synthesized in step 1, and incubated in an oven at 60 °C for 2 h and then allowed to stand at room temperature.

[0027] (5) Under high-speed vortex oscillation, add 9.45 mL H2O, 87 mg SDS, 0.6 mL CuCl2 solution (2 mM), the solution from step (4), 0.25 mL NaOH solution (1 M), and 0.1 mL reducing agent NH2OH·HCl solution (200 mM) to a 20 mL reaction flask in sequence. After standing at room temperature for 20 min, blackbody gold / cuprous oxide Janus nanostructure material can be obtained.

[0028] This invention first synthesizes blackbody gold nanoparticles under solution conditions via ligand modification. Then, small-molecule thiol ligands are introduced to regulate the directional growth of cuprous oxide crystals on the surface of the blackbody gold nanostructure, thereby constructing heterostructured blackbody gold / cuprous oxide nanoparticles. The configurations range from a core-shell structure where cuprous oxide completely encapsulates the blackbody gold seeds, to a Janus semi-encapsulated structure where cuprous oxide crystals of different sizes and quantities grow in an island-like pattern on the blackbody gold surface. This heterostructure exhibits advantages such as high structural uniformity and good reproducibility in preparation. Furthermore, the size and loading quantity of the cuprous oxide crystal component can be flexibly controlled according to the reaction conditions.

[0029] In the prepared heterostructure, blackbody gold exhibits excellent full-spectrum absorption, significantly enhancing the light energy utilization efficiency of the hybrid material. Simultaneously, this structure achieves a typical Mott-Schottky junction between the metal and semiconductor components, with spatial physical separation between the components, allowing for full surface exposure of both materials. This effectively overcomes the low light absorption efficiency of traditional hybrid materials and the charge accumulation problem common in core-shell structures. The resulting blackbody gold / cuprous oxide heterostructure nanomaterial can be directly used for photocatalytic CO2 reduction testing. Compared to pure cuprous oxide crystalline nanoparticles, the blackbody gold / cuprous oxide heterostructure material of this invention exhibits superior reduction efficiency of the C2 product (ethane), demonstrating excellent photocatalytic application prospects. Compared to photocatalytic degradation reactions, photocatalytic CO2 reduction is inherently more challenging due to the need to activate chemically inert CO2 molecules and achieve selective multi-electron proton coupling transfer processes, but it simultaneously provides a direct pathway for solar fuel production and artificial carbon cycling.

[0030] The beneficial effects of this invention are:

[0031] In previous research, we successfully constructed Janus-type Au / Cu₂O heterostructure nanomaterials based on spherical gold nanoparticles (see Angew. Chem. Int. Ed. 2020, 59, 22246–22251). Experimental results show that, compared with traditional core-shell structures, this type of Janus heterostructure exhibits superior performance in suppressing interfacial charge accumulation, improving carrier separation efficiency, and enhancing photoelectric response.

[0032] In this invention, we further combined an interface energy modulation strategy with a crystal plane selective modification mechanism to successfully construct dendritic blackbody gold nanomaterials. By inducing the growth of gold nanoseeds along specific crystal planes using the chiral aliphatic thiol ligand L-cysteine, we obtained gold-gold blackbody nanostructures with multiple branches and high roughness. Due to the effective LSPR coupling between adjacent gold branches, these structures exhibit broad absorption characteristics in the visible-near-infrared spectral range, forming a black gold-gold composite structure. Subsequently, we introduced the thiol ligand 5-amino-2-mercaptobenzimidazole (AMBI) onto the surface of this blackbody gold. By finely adjusting its dosage to control the local interface energy of the gold surface, we achieved directional nucleation and epitaxial growth of cuprous oxide, constructing blackbody gold / cuprous oxide heterostructure nanoparticles with Mott-Schottky junction characteristics.

[0033] The blackbody gold / cuprous oxide heterostructure material prepared by this invention exhibits high morphological uniformity and good batch-to-batch reproducibility. By adjusting the amount of AMBI ligand, the nucleation density and size distribution of cuprous oxide on the blackbody gold surface can be precisely controlled, endowing the material with excellent structural tunability and photocatalytic applicability. Simultaneously, the blackbody gold nanostructure possesses strong broadband light absorption capabilities, significantly improving the material's utilization efficiency of sunlight, particularly demonstrating excellent photoresponse characteristics in the visible to near-infrared band.

[0034] Furthermore, the physical separation structure between the blackbody metal core and the semiconductor cuprous oxide shell ensures full exposure of the two-phase interface. This not only preserves the good interfacial coupling characteristics of the core-shell structure but also effectively avoids interfacial charge accumulation and carrier recombination, which helps to improve the separation and migration efficiency of photogenerated electron-hole pairs, thereby enhancing photocurrent response and photocatalytic activity.

[0035] Experimental results further confirm that the heterostructure constructed in this invention exhibits significantly better charge separation capability and photocatalytic efficiency than single cuprous oxide nanoparticles and traditional gold / cuprous oxide core-shell structures in photocurrent testing and photocatalytic CO2 reduction reaction.

[0036] The raw material Cu2O used in this invention is widely available and inexpensive. The reaction system is environmentally friendly, the synthesis conditions are mild, and the operation is simple, requiring no complex equipment or highly toxic reagents. It exhibits good industrial scalability and environmental compatibility. Therefore, the blackbody gold / cuprous oxide Mott-Schottky heterostructure nanomaterial provided by this invention not only effectively improves the efficiency and stability of photocatalytic reactions but also provides a new material platform and technological pathway for the application of blackbody nanomaterials in fields such as solar energy conversion and environmental purification. It possesses significant scientific research value and broad prospects for industrial application.

[0037] The efficient separation of electron-hole pairs is a key factor determining the photocatalytic performance of semiconductors. To explore the intrinsic relationship between structural configuration and photocurrent response, we conducted systematic photocurrent measurements on a blackbody gold / cuprous oxide core-shell structure and Janus I and Janus II structures. Experimental results show that among nanostructures of similar size, the photocurrent intensity increases sequentially from pure Cu₂O nanocubes to the Au@Cu₂O core-shell structure, and then to Janus I and Janus II structures, with a ratio of approximately 1:1.5:3:6. Among these, the Janus II structure exhibits the most significant photocatalytic activity, mainly attributed to its unique structure achieving a synergistic enhancement of the Schottky barrier effect and space charge separation. The physical separation between the Au and Cu₂O crystals effectively suppresses the recombination of photogenerated electron-hole pairs, thereby improving carrier lifetime and migration efficiency. Further comparison of the Janus I and Janus II structures reveals that the Schottky contact area decreases relatively with increasing Au exposed area. By rationally controlling the Au exposure level, the JanusII structure achieves an optimal balance between the localized surface plasmon resonance (LSPR) enhancement effect and the Schottky contact area, thus exhibiting the strongest photocurrent response. This result demonstrates that interface engineering between metal and semiconductor in heterojunction structures plays a crucial role in improving photocatalytic performance.

[0038] This study systematically investigated the performance and mechanism of the blackbody Au–Cu2O Janus hybrid nanostructure in the visible light-driven photocatalytic reduction of CO2. The results show that, compared to the traditional Au@Cu2O core-shell structure, the Au–Cu2O Janus II catalyst exhibits significant advantages in overall reaction activity and the formation rate and selectivity of C2 products (especially ethane). The performance improvement is mainly attributed to the spatial separation of Au and Cu2O in the Janus structure. This structure effectively promotes the directional migration and efficient separation of photogenerated carriers, maximizing the utilization efficiency of the active interface and significantly reducing carrier recombination losses. Simultaneously, the Janus architecture facilitates the formation, enrichment, and migration of *CO intermediates on the Cu2O surface, providing favorable conditions for the *CO–*CO coupling reaction, thereby promoting C–C bond formation and enhancing the formation of multi-carbon products. Furthermore, the Au–Cu2O Janus II catalyst demonstrates excellent structural and reaction stability in multiple CO2 reduction cycles, maintaining good crystal structure integrity before and after the reaction, showing promising potential for practical applications. In summary, the Janus structure of blackbody Au-Cu2O not only reveals the structural advantages of Janus heterostructures in improving photocatalytic CO2 reduction efficiency and multi-carbon product selectivity, but also provides a generalizable structural construction strategy for designing efficient and stable multi-carbon product photocatalytic systems. The Au–Cu2O Janus II catalyst achieved 56% ethane selectivity, a 19 percentage point improvement (approximately 51% relative improvement) compared to the highest reported value (37%). Simultaneously, the ethane formation rate reached 6.58 g·mol⁻¹. -1 ·h -1 This is higher than the highest previously reported value (1.92 g·mol⁻¹). -1 ·h -1 The catalytic performance is improved by approximately 243% (about 3.4 times), demonstrating significantly better catalytic performance than existing systems.

[0039] The blackbody gold / cuprous oxide nanohybrid material of this invention exhibits significant potential for improving photocatalytic performance due to its unique plasmon enhancement effect and catalytic synergy. The blackbody gold nanostructure possesses broad-spectrum absorption characteristics, enabling efficient light capture in the visible to near-infrared range, thereby significantly broadening the system's photoresponse range and improving solar energy utilization efficiency. Compared to traditional gold nanoparticles, its "blackbody" characteristic stems from the multiple light scattering and enhanced local electromagnetic field caused by the complex nanostructure, allowing for more complete absorption and localization of incident light. Under illumination, blackbody gold generates a strong localized surface plasmon resonance (LSPR) effect, forming an enhanced electric field on the metal surface and inducing the generation of high-energy hot electrons. These hot electrons can be injected across the metal-semiconductor interface into the cuprous oxide conduction band, effectively increasing the concentration of photogenerated carriers and promoting the reduction reaction. Simultaneously, the localized photothermal effect generated during plasma decay can lower the activation energy, further accelerating surface reaction kinetics. This synergistic mechanism significantly improves photocatalytic reaction efficiency and provides favorable conditions for multi-electron reduction reactions, thereby significantly enhancing catalytic selectivity.

[0040] In this study, a series of gold / cuprous oxide hybrid materials with blackbody properties were synthesized using a solution-phase seed growth method (see...). Figure 1 By controlling the interfacial energy, particularly by modifying gold seeds with different proportions of the strong thiol ligand 5-amino-2-mercaptobenzimidazole (AMBI), a continuous and tunable transformation from core-shell structures to different types of Janus structures was successfully achieved. This structural regulation strategy provides a new approach for in-depth research on the performance characteristics of blackbody materials and semiconductor heterojunctions. Experimental results show that the blackbody gold / cuprous oxide heterojunction structure exhibits significantly higher yields of C2 products (especially ethane) in the photocatalytic CO2 reduction reaction compared to the core-shell structure, representing a two-fold increase in catalytic activity. This achievement provides new catalyst design ideas not only for the field of photocatalysis but also for the application of blackbody materials and semiconductor heterojunctions in photocatalysis.

[0041] Compared with previously authorized gold sphere / cuprous oxide composite materials for photocatalytic degradation reactions, this invention differs fundamentally in terms of technical objectives, reaction mechanisms, and structural and functional design.

[0042] Firstly, in terms of application targets, existing technologies are mainly used for the photocatalytic degradation of organic pollutants, with the core objective being to utilize strongly oxidizing species (such as ·OH, ·O2) to achieve the degradation. - The present invention targets the photocatalytic CO2 reduction reaction, which aims to convert thermodynamically stable CO2 molecules into high-value-added fuel molecules (such as CO, CH4 and C2 hydrocarbons). This is a process of converting solar energy into chemical energy. The two technologies have significantly different directions and application scenarios.

[0043] Secondly, the two types of reactions differ fundamentally in their reaction mechanisms. Photocatalytic degradation mainly relies on oxidation reactions driven by photogenerated holes or oxidative radicals, which are usually thermodynamically favorable processes; while CO2 reduction involves the coupling and transfer of multiple electrons and protons, requiring the activation of chemically inert CO2 molecules and the simultaneous suppression of the competitive hydrogen evolution reaction, placing higher demands on the energy position, lifetime, and interfacial transport efficiency of photogenerated electrons. Therefore, the material design principles in degradation systems cannot be directly applied to CO2 reduction systems. Attached Figure Description

[0044] The present invention will be further described below with reference to the accompanying drawings.

[0045] Figure 1 SEM image of the blackbody gold structure prepared in Example 1;

[0046] Figure 2 SEM image of the blackbody gold / cuprous oxide core-shell structure prepared in Example 2;

[0047] Figure 3 SEM image of the blackbody gold / cuprous oxide Janus I structure prepared in Example 3;

[0048] Figure 4 SEM image of the blackbody gold / cuprous oxide Janus II structure prepared in Example 4;

[0049] Figure 5 SEM image of the blackbody gold / cuprous oxide Janus III structure prepared in Example 5;

[0050] Figure 6 SEM image of the blackbody gold / cuprous oxide Janus IV structure prepared in Example 6;

[0051] Figure 7 SEM image of the blackbody gold / cuprous oxide Janus V structure prepared in Example 7;

[0052] Figure 8 Absorption spectra of blackbody gold, blackbody gold / cuprous oxide core-shell structure, Janus I structure, and Janus II structure prepared for gold nanospheres, Examples 1, 2, 3, and 4;

[0053] Figure 9 HRTEM image and elemental electron spectroscopy scan of the bulk gold / cuprous oxide Janus II structure prepared in Example 4;

[0054] Figure 10XRD polycrystalline diffraction patterns of pure cuprous oxide crystals, blackbody gold, blackbody gold / cuprous oxide core-shell structure, Janus I, and Janus II structures prepared in Examples 1, 2, 3, and 4;

[0055] Figure 11 XPS spectra of the blackbody gold / cuprous oxide Janus II structure prepared in Example 4;

[0056] Figure 12 Photocurrent it curves of the blackbody gold / cuprous oxide Janus II, Janus III, Janus IV, and Janus V structures prepared in Examples 4, 5, 6, and 7 are shown.

[0057] Figure 13 The blackbody gold / cuprous oxide core-shell structure, Janus I and Janus II structure prepared in Examples 2, 3 and 4, and the photocurrent it curve test diagram of pure cuprous oxide;

[0058] Figure 14 Electrochemical impedance spectroscopy (EIS) spectra of blackbody gold / cuprous oxide core-shell structure, Janus I structure, Janus II structure, and pure cuprous oxide prepared in Examples 2, 3, and 4.

[0059] Figure 15 The test diagrams show the photocatalytic CO2 reduction of blackbody gold and blackbody gold / cuprous oxide core-shell Janus II structures prepared in Examples 2 and 4. Detailed Implementation

[0060] Example 1: A method for preparing blackbody gold / cuprous oxide heterostructure nanophotocatalytic materials with different morphologies, comprising the following steps:

[0061] (1) Preparation of gold nanospheres: Gold nanospheres with a particle size of 60 nm were centrifuged at 6000 rpm for 15 min, the supernatant was removed, and the centrifugation was repeated once to remove excess surfactant sodium citrate. The resulting precipitate was redispersed in an equal volume of deionized water.

[0062] (2) Synthesis of blackbody gold nanoparticles: Under high-speed vortex oscillation conditions, the following components were added to the reaction vessel in sequence: 1.5 mL CTAB (100 mM), 0.5 mL HAuCl4 (50 mM), 0.5 mL AA (100 mM), 0.5 mL L-cysteine ​​(10 mM), 8 mL deionized water and 1 mL of the gold ball dispersion prepared in step (1). After mixing, the mixture was reacted at room temperature for 15 min to obtain blackbody gold nanoparticles with a dendritic structure. Figure 1This is the SEM image of the blackbody gold obtained in this experiment.

[0063] Example 2: A method for preparing blackbody gold / cuprous oxide heterostructure nanophotocatalytic materials with different morphologies, comprising the following steps:

[0064] (1) Preparation of gold nanospheres: Gold nanospheres with a particle size of 60 nm were centrifuged at 6000 rpm for 15 min, the supernatant was removed, and the centrifugation was repeated once to remove excess surfactant sodium citrate. The resulting precipitate was redispersed in an equal volume of deionized water.

[0065] (2) Synthesis of blackbody gold nanoparticles: Under high-speed vortex oscillation conditions, the following components were added to the reaction vessel in sequence: 1.5 mL CTAB (100 mM), 0.5 mL HAuCl4 (50 mM), 0.5 mL AA (100 mM), 0.5 mL L-cysteine ​​(10 mM), 8 mL deionized water and 1 mL of the gold ball dispersion prepared in step (1). After mixing, the mixture was reacted at room temperature for 15 min to obtain blackbody gold nanoparticles with a dendritic structure.

[0066] (3) The synthesized blackbody gold nanoparticles were centrifuged at 6000 rpm for 15 min to remove the supernatant, and centrifuged twice to remove excess surfactant CTAB (hexadecyltrimethylammonium bromide), and then dispersed in the same volume of water.

[0067] (4) Under high-speed vortex oscillation, 0 μL of thiol ligand AMBI 10 mM was injected into 1 mL of blackbody gold nanomaterial synthesized in step 1, and incubated in an oven at 60°C for 2 h and then allowed to stand at room temperature.

[0068] (5) Under high-speed vortex oscillation, add 9.45 mL H2O, 87 mg SDS, 0.6 mL CuCl2 solution (2 mM), the solution from step (4), 0.25 mL NaOH solution (1 M), and 0.1 mL reducing agent NH2OH·HCl solution (200 mM) to a 20 mL reaction flask in sequence. After standing at room temperature for 20 min, the blackbody gold / cuprous oxide heterojunction nanostructure material can be obtained. Figure 2 This is a SEM image of the blackbody gold / cuprous oxide core-shell structure obtained in this experiment.

[0069] Example 3: A method for preparing blackbody gold / cuprous oxide heterostructure nanophotocatalytic materials with different morphologies, comprising the following steps:

[0070] (1) Preparation of gold nanospheres: Gold nanospheres with a particle size of 60 nm were centrifuged at 6000 rpm for 15 min, the supernatant was removed, and the centrifugation was repeated once to remove excess surfactant sodium citrate. The resulting precipitate was redispersed in an equal volume of deionized water.

[0071] (2) Synthesis of blackbody gold nanoparticles: Under high-speed vortex oscillation conditions, the following components were added to the reaction vessel in sequence: 1.5 mL CTAB (100 mM), 0.5 mL HAuCl4 (50 mM), 0.5 mL AA (100 mM), 0.5 mL L-cysteine ​​(10 mM), 8 mL deionized water and 1 mL of the gold ball dispersion prepared in step (1). After mixing, the mixture was reacted at room temperature for 15 min to obtain blackbody gold nanoparticles with a dendritic structure.

[0072] (3) The synthesized blackbody gold nanoparticles were centrifuged at 6000 rpm for 15 min to remove the supernatant, and centrifuged twice to remove excess surfactant CTAB (hexadecyltrimethylammonium bromide), and then dispersed in the same volume of water.

[0073] (4) Under high-speed vortex oscillation, 5 μL of the thiol ligand AMBI (10 mM) was injected into 1 mL of the blackbody gold nanomaterial synthesized in step 1, and incubated in an oven at 60°C for 2 h and then allowed to stand at room temperature.

[0074] (5) Under high-speed vortex oscillation, add 9.45 mL H2O, 87 mg SDS, 0.6 mL CuCl2 solution (2 mM), the solution from step (4), 0.25 mL NaOH solution (1 M), and 0.1 mL reducing agent NH2OH·HCl solution (200 mM) to a 20 mL reaction flask in sequence. After standing at room temperature for 20 min, the blackbody gold / cuprous oxide heterojunction nanostructure material can be obtained. Figure 3 This is a SEM image of the blackbody gold / cuprous oxide Janus I structure obtained in this experiment.

[0075] Example 4: A method for preparing blackbody gold / cuprous oxide heterostructure nanophotocatalytic materials with different morphologies, comprising the following steps:

[0076] (1) Preparation of gold nanospheres: Gold nanospheres with a particle size of 60 nm were centrifuged at 6000 rpm for 15 min, the supernatant was removed, and the centrifugation was repeated once to remove excess surfactant sodium citrate. The resulting precipitate was redispersed in an equal volume of deionized water.

[0077] (2) Synthesis of blackbody gold nanoparticles: Under high-speed vortex oscillation conditions, the following components were added to the reaction vessel in sequence: 1.5 mL CTAB (100 mM), 0.5 mL HAuCl4 (50 mM), 0.5 mL AA (100 mM), 0.5 mL L-cysteine ​​(10 mM), 8 mL deionized water and 1 mL of the gold ball dispersion prepared in step (1). After mixing, the mixture was reacted at room temperature for 15 min to obtain blackbody gold nanoparticles with a dendritic structure.

[0078] (3) The synthesized blackbody gold nanoparticles were centrifuged at 6000 rpm for 15 min to remove the supernatant, and centrifuged twice to remove excess surfactant CTAB (hexadecyltrimethylammonium bromide), and then dispersed in the same volume of water.

[0079] (4) Under high-speed vortex oscillation, 10 μL of the thiol ligand AMBI (10 mM) was injected into 1 mL of the blackbody gold nanomaterial synthesized in step 1, and incubated in an oven at 60°C for 2 h and then allowed to stand at room temperature.

[0080] (5) Under high-speed vortex oscillation, add 9.45 mL H2O, 87 mg SDS, 0.6 mL CuCl2 solution (2 mM), the solution from step (4), 0.25 mL NaOH solution (1 M), and 0.1 mL reducing agent NH2OH·HCl solution (200 mM) to a 20 mL reaction flask in sequence. After standing at room temperature for 20 min, the blackbody gold / cuprous oxide heterojunction nanostructure material can be obtained. Figure 4 This is a SEM image of the blackbody gold / cuprous oxide Janus II structure obtained in this experiment.

[0081] Figure 1 Scanning electron microscope image of the blackbody Au prepared in Example 1. The average size of the obtained blackbody gold seed branches is 320 nm, and each particle has approximately 30 branches.

[0082] Figure 2 Example 2. Scanning electron microscope image of the blackbody Au@Cu2O core-shell structure prepared in Example 2. The Cu2O nanocubes in the core-shell structure are highly uniform in shape and size (average side length 70 nm). Due to their close packing, the number of Cu2O nanocubes cannot be precisely counted. The unique feature of this core-shell structure is its deviation from the traditional morphology—instead of a single uniform shell, numerous tiny cubic Cu2O crystals aggregate and seamlessly cover the dendritic structure, forming a complete encapsulation.

[0083] Figure 3Scanning electron microscope (SEM) image of the blackbody Au-Cu₂O Janus I structure prepared in Example 3. Interestingly, compared to the core-shell structure, the density of the Cu₂O cubes is significantly reduced, thus forming a Janus-like Au-Cu₂O core-satellite structure. Due to the asymmetry of the interface contact and the spatial separation of functional domains, this core-satellite configuration can be reasonably regarded as a Janus-type heterostructure, which will be referred to as the Janus structure below. Specifically, with AMBI at 5 μL (10 μM) and CuCl₂ (0.6 mL) at a concentration of 2 mM, the growth of Cu₂O on branched Au seeds formed a grape-like structure (Janus I). The average side length of the Cu₂O cubes is approximately 143 nm, and each Au-Cu₂O hybrid structure contains an average of 16 Cu₂O cube crystals.

[0084] Figure 4 Scanning electron microscope (SEM) image of the blackbody Au-Cu₂O Janus II structure prepared in Example 4. When AMBI was 10 μL (10 μM) and CuCl₂ (0.6 mL) was 2 mM, the size and number of Cu₂O particles of the Au-Cu₂O double-sided structure changed significantly (Janus II). The edge length of Cu₂O increased to 255 nm, and the average number of Cu₂O islands decreased to 6.

[0085] Figure 5 Scanning electron microscope (SEM) image of the blackbody Au-Cu₂O Janus III structure prepared in Example 5. When AMBI was 10 μL (10 μM) and CuCl₂ (0.6 mL) was 1 mM, the size of the Cu₂O islands was 140 nm. Statistical analysis also showed that the number of Cu₂O islands on the Janus structure was approximately 5.

[0086] Figure 6 Scanning electron microscope (SEM) image of the blackbody Au-Cu₂O Janus IV structure prepared in Example 6. When AMBI was 10 μL (10 μM) and CuCl₂ (0.6 mL) was 4 mM, the size of the Cu₂O islands increased to 313 nm. Meanwhile, statistical analysis showed that the number of Cu₂O islands on the Janus structure decreased to two.

[0087] Figure 7 Scanning electron microscope (SEM) image of the blackbody Au-Cu₂O Janus V structure prepared in Example 7. When AMBI was 10 μL (10 μM) and CuCl₂ (0.6 mL) was 6 mM, the size of the Cu₂O islands increased to 433 nm. Statistical analysis also showed that the number of Cu₂O islands on the Janus structure was approximately two.

[0088] Figure 8 The Au–Cu₂O heterostructures exhibit the characteristic UV-Vis-NIR absorption behavior of Cu₂O crystals, with a weak absorption peak at approximately 450 nm, which is considered to correspond to the bandgap absorption of Cu₂O. Based on the density and spacing of the spikes in the blackbody gold, we hypothesize that localized surface plasmon resonance (LSPR) coupling between the spikes is the main reason for its broad-band optical absorption.

[0089] Figure 9 The images show HRTEM images and linear and area scans of the elemental electron spectrometry for the blackbody gold / cuprous oxide Janus II structure prepared in Example 4. To further resolve structural details, individual Au–Cu₂O Janus nanoparticles were characterized using high-resolution transmission electron microscopy (HRTEM). Figure 9 As shown in Figure a, large-area, regularly arranged lattice fringes can be observed in both the Au and Cu₂O regions, and their orientations are well-consistent, indicating that single-crystal Cu₂O has achieved epitaxial growth on a single-crystal Au structure. In the Fast Fourier Transform (FFT) image ( Figure 9 (b) The diffraction spots in region 2 and region 3 are completely consistent, further proving that the Cu2O cubic region has single-crystal characteristics.

[0090] Furthermore, energy-dispersive X-ray spectroscopy (EDS) elemental mapping and line scan analysis were used to reveal the elemental distribution in the Au–Cu₂OJanus structure. EDS results ( Figure 9 e–j) shows that the Au and Cu2O components are clearly separated in space, which is consistent with the HAADF-STEM images of individual Janus particles ( Figure 9 e) Highly consistent. It is worth noting that the sulfur element distribution map ( Figure 9 j) This indicates that the AMBI ligand exists simultaneously in both the Au and Cu₂O regions, which can be attributed to the –SH group's effect on both Au and Cu. + The species exhibits strong coordination affinity. This result confirms the presence of AMBI ligands at the Au–Cu2O interface, supporting the regulatory mechanism of ligand-modified interfacial energy in the Janus structure.

[0091] Figure 10XRD polycrystalline diffraction patterns of pure cuprous oxide crystals, blackbody gold, blackbody gold / cuprous oxide core-shell structure, Janus I, and Janus II structures prepared in Examples 1, 2, 3, and 4. The XRD patterns show four distinct diffraction peaks at 35.99°, 41.85°, 60.93°, and 73.17°, corresponding to the (111), (200), (220), and (311) crystal planes of Cu2O (JCPDS card number: 00-077-0199). In addition, five weaker diffraction peaks were observed at 37.67°, 43.87°, 64.15°, 77.15° and 81.49°, which were attributed to the (111), (200), (220), (311) and (222) crystal planes of Au (JCPDS card number: 04-0784), further confirming the coexistence of Au and Cu2O crystal phases in the sample.

[0092] Figure 11 XPS spectra of the blackbody gold / cuprous oxide Janus II structure prepared in Example 4. The XPS spectra show a double peak in the O1s spectrum at 529.9 eV and 531.3 eV, corresponding to O in Cu2O, respectively. 2- Ions and hydroxyl groups and water molecules adsorbed on the material surface ( Figure 11 In the Cu 2p spectrum, the characteristic peaks at 932.2 eV and 951.9 eV belong to the Cu 2p3 / 2 and Cu 2p1 / 2 orbitals of Cu+, respectively, confirming that Cu exists in the +1 valence state; while the characteristic peaks at 934.2 eV and 954.3 eV correspond to Cu+. 2+ 2p 3 / 2 and 2p 1 / 2 These peaks may originate from unreacted Cu(OH)₂·xH₂O on the surface, or they may be due to oxidation to CuO during the synthesis and characterization of Janus II material. The Au 4f spectrum shows a double peak at 83.9 eV and 87.6 eV, which is caused by spin-orbit splitting of the Au 4f orbital, indicating that Au exists in a zero-valence state in the Janus II structure.

[0093] Figure 12 show, Figure 13The photocurrent test results of the black Au-Cu2O Janus II, Janus III, Janus IV, and Janus V structures prepared in Examples 4, 5, 6, and 7 are shown. The photocurrent intensity ratio is Janus II : Janus IV : Janus V : Janus III = 1.7 : 1.3 : 1.2 : 1. We speculate that appropriately increasing the metal coverage helps to expand the Schottky contact area, thereby promoting the separation of photogenerated carriers; however, excessive coverage may inhibit charge diffusion and transfer. The Janus II structure achieves a better balance between contact area and charge dissipation, thus exhibiting the best photoelectric response performance.

[0094] Figure 13 The photocurrent ratios of pure Cu2O nanocubes, the blackbody gold / cuprous oxide core-shell structures prepared in Examples 2, 3, and 4, and the Janus I and Janus II structures are 1:1.5:3:6, respectively. The photocurrent of the Au@Cu2O core-shell structure is approximately 1.5 times that of the pure Cu2O cube, an improvement mainly attributed to the formation of the Au–Cu2O Schottky junction. Since the work function of gold (Au) (5.10 eV) is lower than that of p-type Cu2O (5.27 eV), the Schottky barrier formed at the interface has a rectifying effect, promoting the unidirectional migration of photogenerated electrons from Cu2O to the metallic Au region. Similarly, the Janus II structure also forms a Schottky barrier, and its photocurrent is approximately 6 times higher than that of pure Cu2O, significantly superior to the other structures. This enhancement effect may originate from its partially exposed Au region, effectively reducing recombination losses caused by charge accumulation.

[0095] Figure 14 Electrochemical impedance spectroscopy (EIS) analyses were performed on four structures: Cu₂O nanocubes, core-shell structures, Janus I, and Janus II, to investigate their interfacial charge transport characteristics. All samples exhibited a distinct semicircular arc in the high-frequency region of their Nyquist plots, a characteristic typically corresponding to interfacial charge transport resistance. Notably, the Janus II structure had the smallest semicircular diameter, indicating the lowest charge transport resistance. In contrast, Janus I and the core-shell structures showed moderate arc radii, while the pristine Cu₂O exhibited the largest semicircle, reflecting a relatively slow interfacial charge transport process.

[0096] Figure 15The photocatalytic performance of the Au–Cu₂O hybrid nanostructure was evaluated. CO₂ photocatalytic reduction test: 5 mg of nanoparticles were typically dispersed in 10 mL of H₂O and placed in a sealed quartz reactor. The reactor was then evacuated and purged three times with CO₂ gas to remove residual air, followed by the introduction of CO₂ (99.9999%) to atmospheric pressure. The photocatalytic CO₂ reduction reaction was carried out under visible light irradiation using a 300 W xenon lamp (PLS-SXE300, Perfectlight) equipped with a 420 nm cutoff filter (λ > 420 nm). The reaction temperature was maintained at 25 °C using a circulating water cooling system. Gas phase products (CO, CH₄, and C₂H₆) were analyzed using an online gas chromatograph (GC-9070, Fuli Instruments), equipped with a thermal conductivity detector (TCD) and a flame ionization detector (FID). The detector temperatures were set to 120 °C for TCD and 180 °C for FID, with an injection volume of 1 mL. Liquid products were quantitatively analyzed using a high-performance liquid chromatograph (Agilent 1260 Infinity II). Quantification of gaseous products was achieved by establishing a calibration curve using the external standard method. Specifically, a known volume of standard gas was injected into a vacuum reactor using a gas-tight injector, and the corresponding GC peak areas were recorded to establish a standard calibration curve.

[0097] A blackbody Au–Cu₂O hybrid nanostructure was used as a catalyst to carry out photocatalytic CO₂ reduction under xenon lamp irradiation. As shown in the figure, the maximum formation rates of CO, CH₄, and C₂H₆ by the Au–Cu₂O Janus II catalyst were 6.575, 1.717, and 7.621 μmol·g⁻¹, respectively. -1 ·h -1 In contrast, the Au@Cu2O core-shell structure catalyst exhibits lower overall reactivity, with CO, CH4, and C2H6 formation rates of 5.891, 1.452, and 4.071 μmol·g⁻¹, respectively. -1 ·h -1 It is worth noting that the Janus II structure exhibits a significant advantage in C2H6 formation, with a yield almost twice that of the core-shell structure (Example 2). Stability is one of the key parameters for the practical application of high-performance photocatalysts. Multiple CO2 reduction cycle experiments were conducted using the blackbody Au–Cu2O Janus II catalyst as the research object. Figure 15(d) The yield of C2H6 was quantitatively analyzed every 2 hours. The results showed that the amount of C2H6 produced remained essentially constant throughout the four consecutive cycles, and its crystal structure was well preserved, demonstrating the excellent catalytic stability and structural robustness of the catalyst. Furthermore, compared with recently reported photocatalysts (Table 1), this system exhibited competitive catalytic efficiency. Especially in the Cu2O-based heterojunction photocatalyst system, the Janus II catalyst obtained in this study showed the highest yield and selectivity for C2 product formation, demonstrating significant performance advantages.

[0098] The Au–Cu₂O Janus II catalyst achieved 56% ethane selectivity, a 19 percentage point improvement (approximately 51% relative increase) compared to the highest reported value (37%). Simultaneously, the ethane formation rate reached 6.58 g·mol⁻¹. -1 ·h -1 This is higher than the highest previously reported value (1.92 g·mol⁻¹). -1 ·h -1 The catalytic performance is improved by approximately 243% (about 3.4 times), demonstrating significantly better catalytic performance than existing systems.

[0099] Table 1. Comparative studies of similar photocatalytic systems in recent literature on carbon dioxide reduction performance.

[0100]

[0101] Example 5: A method for preparing blackbody gold / cuprous oxide heterostructure nanophotocatalytic materials with different morphologies, comprising the following steps:

[0102] (1) Preparation of gold nanospheres: Gold nanospheres with a particle size of 60 nm were centrifuged at 6000 rpm for 15 min, the supernatant was removed, and the centrifugation was repeated once to remove excess surfactant sodium citrate. The resulting precipitate was redispersed in an equal volume of deionized water.

[0103] (2) Synthesis of blackbody gold nanoparticles: Under high-speed vortex oscillation conditions, the following components were added to the reaction vessel in sequence: 1.5 mL CTAB (100 mM), 0.5 mL HAuCl4 (50 mM), 0.5 mL AA (100 mM), 0.5 mL L-cysteine ​​(10 mM), 8 mL deionized water and 1 mL of the gold ball dispersion prepared in step (1). After mixing, the mixture was reacted at room temperature for 15 min to obtain blackbody gold nanoparticles with a dendritic structure.

[0104] (3) The synthesized blackbody gold nanoparticles were centrifuged at 6000 rpm for 15 min to remove the supernatant, and centrifuged twice to remove excess surfactant CTAB (hexadecyltrimethylammonium bromide), and then dispersed in the same volume of water.

[0105] (4) Under high-speed vortex oscillation, 10 μL of the thiol ligand AMBI (10 mM) was injected into 1 mL of the blackbody gold nanomaterial synthesized in step 1, and incubated in an oven at 60°C for 2 h before being allowed to stand at room temperature.

[0106] (5) Under high-speed vortex oscillation, add 9.45 mL H2O, 87 mg SDS, 0.6 mL CuCl2 solution (1 mM), the solution from step (4), 0.25 mL NaOH solution (1 M), and 0.1 mL reducing agent NH2OH·HCl solution (200 mM) to a 20 mL reaction flask in sequence. After standing at room temperature for 20 min, the blackbody gold / cuprous oxide heterojunction nanostructure material can be obtained. Figure 5 This is a SEM image of the blackbody gold / cuprous oxide Janus III structure obtained in this experiment.

[0107] Example 6: A method for preparing blackbody gold / cuprous oxide heterostructure nanophotocatalytic materials with different morphologies, comprising the following steps:

[0108] (1) Preparation of gold nanospheres: Gold nanospheres with a particle size of 60 nm were centrifuged at 6000 rpm for 15 min, the supernatant was removed, and the centrifugation was repeated once to remove excess surfactant sodium citrate. The resulting precipitate was redispersed in an equal volume of deionized water.

[0109] (2) Synthesis of blackbody gold nanoparticles: Under high-speed vortex oscillation conditions, the following components were added to the reaction vessel in sequence: 1.5 mL CTAB (100 mM), 0.5 mL HAuCl4 (50 mM), 0.5 mL AA (100 mM), 0.5 mL L-cysteine ​​(10 mM), 8 mL deionized water and 1 mL of the gold ball dispersion prepared in step (1). After mixing, the mixture was reacted at room temperature for 15 min to obtain blackbody gold nanoparticles with a dendritic structure.

[0110] (3) The synthesized blackbody gold nanoparticles were centrifuged at 6000 rpm for 15 min to remove the supernatant, and centrifuged twice to remove excess surfactant CTAB (hexadecyltrimethylammonium bromide), and then dispersed in the same volume of water.

[0111] (4) Under high-speed vortex oscillation, 10 μL of the thiol ligand AMBI (10 mM) was injected into 1 mL of the blackbody gold nanomaterial synthesized in step 1, and incubated in an oven at 60°C for 2 h before being allowed to stand at room temperature.

[0112] (5) Under high-speed vortex oscillation, add 9.45 mL H2O, 87 mg SDS, 0.6 mL CuCl2 solution (4 mM), the solution from step (4), 0.25 mL NaOH solution (1 M) and 0.1 mL reducing agent NH2OH·HCl solution (200 mM) to a 20 mL reaction flask in sequence. After standing at room temperature for 20 min, the blackbody gold / cuprous oxide heterojunction nanostructure material can be obtained. Figure 6 This is a SEM image of the blackbody gold / cuprous oxide Janus IV structure obtained in this experiment.

[0113] Example 7: A method for preparing blackbody gold / cuprous oxide heterostructure nanophotocatalytic materials with different morphologies, comprising the following steps:

[0114] (1) Preparation of gold nanospheres: Gold nanospheres with a particle size of 60 nm were centrifuged at 6000 rpm for 15 min, the supernatant was removed, and the centrifugation was repeated once to remove excess surfactant sodium citrate. The resulting precipitate was redispersed in an equal volume of deionized water.

[0115] (2) Synthesis of blackbody gold nanoparticles: Under high-speed vortex oscillation conditions, the following components were added to the reaction vessel in sequence: 1.5 mL CTAB (100 mM), 0.5 mL HAuCl4 (50 mM), 0.5 mL AA (100 mM), 0.5 mL L-cysteine ​​(10 mM), 8 mL deionized water and 1 mL of the gold ball dispersion prepared in step (1). After mixing, the mixture was reacted at room temperature for 15 min to obtain blackbody gold nanoparticles with a dendritic structure.

[0116] (3) The synthesized blackbody gold nanoparticles were centrifuged at 6000 rpm for 15 min to remove the supernatant, and centrifuged twice to remove excess surfactant CTAB (hexadecyltrimethylammonium bromide), and then dispersed in the same volume of water.

[0117] (4) Under high-speed vortex oscillation, 10 μL of the thiol ligand AMBI (10 mM) was injected into 1 mL of the blackbody gold nanomaterial synthesized in step 1, and incubated in an oven at 60°C for 2 h and then allowed to stand at room temperature.

[0118] (5) Under high-speed vortex oscillation, add 9.45 mL H2O, 87 mg SDS, 0.6 mL CuCl2 solution (6 mM), the solution from step (4), 0.25 mL NaOH solution (1 M), and 0.1 mL reducing agent NH2OH·HCl solution (200 mM) to a 20 mL reaction flask in sequence. After standing at room temperature for 20 min, the blackbody gold / cuprous oxide heterojunction nanostructure material can be obtained. Figure 7 This is a SEM image of the blackbody gold / cuprous oxide Janus V structure obtained in this experiment.

[0119] Finally, it should be emphasized that the range of technical parameters such as concentration, volume, and aspect ratio mentioned in this invention is adjustable and not limited by the actual parameters mentioned herein. Furthermore, the above specific description of this invention is only for illustrating the technical solutions of this invention and is not intended to limit it to the specific examples described herein. Those skilled in the art should understand that any modifications or equivalent substitutions to this invention to achieve the same technical effect are within the scope of protection of this invention. This invention is not limited to the specific technical solutions described in the above embodiments; all technical solutions formed by equivalent substitutions are within the scope of protection claimed by this invention.

Claims

1. A method for preparing a multi-morphological blackbody gold / cuprous oxide heterostructure nanophotocatalytic material, characterized in that... The process includes the following steps: First, the surfactant hexadecyltrimethylammonium bromide (CTAB), chloroauric acid trihydrate, ascorbic acid, and L-cysteine ​​are mixed to obtain blackbody gold nanoparticles; then, the surface energy of the blackbody gold nanoparticles is modified with the thiol ligand 5-amino-2-mercaptobenzimidazole (AMBI); subsequently, the surfactant sodium dodecyl sulfate (SDS), the precursor copper chloride, sodium hydroxide, and the reducing agent hydroxylamine hydrochloride solution are added to react, thereby growing a series of blackbody gold / cuprous oxide heterostructure nanophotocatalytic materials with different morphologies on the surface of the blackbody gold nanoparticles.

2. The method for preparing blackbody gold / cuprous oxide heterostructure nanophotocatalytic materials with different morphologies according to claim 1, characterized in that: Includes the following steps: (1) Gold nanoparticles with a particle size of 60 nm were synthesized. The final product was centrifuged at 6000 rpm for 15 min to remove the supernatant. The centrifugation was repeated once to remove excess surfactant sodium citrate. The resulting precipitate was redispersed in an equal volume of deionized water. (2) 1.5 mL of cetyltrimethylammonium bromide (CTAB) solution (100 mM), 0.5 mL of chloroauric acid trihydrate (HAuCl4·3H2O) solution (50 mM), 0.5 mL of ascorbic acid (AA) solution (100 mM), 0.5 mL of L-cysteine ​​solution (10 mM), 1 mL of the gold nanospheres synthesized in the previous step, and 8 mL of deionized water were added to the reaction system in sequence, mixed evenly, and reacted at room temperature for 20 min to prepare black black body gold nanoparticles with dendritic structure; (3) The synthesized blackbody gold nanoparticles were centrifuged at 6000 rpm for 15 min to remove the supernatant, centrifuged twice to remove excess surfactant CTAB, and dispersed in the same volume of water. (4) Under high-speed vortex oscillation, the 1 mL volume of blackbody gold nanoparticles obtained above was mixed with different volumes of thiol ligand 5-amino-2-mercaptobenzimidazole (AMBI) solution (10 mM), and the mixture was incubated in a 60℃ oven for 2 h before being cooled to room temperature. (5) Under high-speed vortex oscillation, add 9.45 mL H2O, 87 mg sodium dodecyl sulfate (SDS), 0.6 mL CuCl2 solution of different concentrations, the solution from step (4), 0.25 mL NaOH solution (1 M) and 0.1 mL reducing agent NH2OH·HCl solution (200 mM) to a 20 mL reaction flask in sequence. After standing at room temperature for 20 min, a series of blackbody gold / cuprous oxide heterostructure nanophotocatalytic materials can be obtained. By controlling the amount of CuCl2 added as a precursor, the size and quantity distribution of cuprous oxide crystals in the resulting blackbody gold / cuprous oxide heterostructure can be regulated.

3. The method for preparing blackbody gold / cuprous oxide heterostructure nanophotocatalytic materials with different morphologies according to claim 1, characterized in that: The molar ratio of L-cysteine ​​solution to the reducing agent ascorbic acid is 1–5:10000.

4. The method for preparing heterojunction nanophotocatalytic materials of different morphologies of blackbody gold / cuprous oxide according to claim 1, characterized in that: The diameter of the gold sphere used in step (1) can be 10 to 100 nm.

5. The method for preparing blackbody gold / cuprous oxide heterojunction nanomaterials with different morphologies according to claim 1, characterized in that: The molar ratio of the cuprous oxide precursor solution to the sodium hydroxide solution is 3–10:

650.

6. The method for preparing heterojunction nanomaterials of blackbody gold / cuprous oxide with different morphologies according to claim 1, characterized in that: In step (3), the amount of thiol ligand AMBI (10 mM) used ranges from 1 μL to 15 μL; in step (4), the concentration range of 0.6 mL of copper chloride ranges from 2 mM to 30 mM.

7. The method for preparing heterojunction nanomaterials of blackbody gold / cuprous oxide with different morphologies according to claim 1, characterized in that: Includes the following steps: (1) The synthesized blackbody gold nanoparticles were centrifuged at 6000 rpm for 15 min to remove the supernatant, centrifuged twice to remove excess surfactant CTAB, and dispersed in the same volume of water. (2) Under high-speed vortex oscillation, 10 μL of the thiol ligand AMBI (10 mM) was injected into 1 mL of the blackbody gold nanomaterial synthesized in step 1, and incubated in an oven at 60 °C for 2 h and then allowed to stand at room temperature. (3) Under high-speed vortex oscillation, add 9.45 mL H2O, 87 mg SDS, 0.6 mL CuCl2 solution (2 mM), the solution from step (2), 0.25 mL NaOH solution (1 M) and 0.1 mL reducing agent NH2OH·HCl solution (200 mM) to a 20 mL reaction flask in sequence. After standing at room temperature for 20 min, the blackbody gold / cuprous oxide heterostructure nanomaterial Janus II can be obtained.

8. Blackbody gold / cuprous oxide heterojunction nanocatalytic materials with different morphologies prepared by the method according to any one of claims 1-7.

9. The application of the blackbody gold / cuprous oxide heterojunction nanomaterials with different morphologies according to claim 8, characterized in that: It can be used for photocatalytic CO2 reduction reactions.

10. The application of the blackbody gold / cuprous oxide heterojunction nanomaterial prepared according to claim 7, characterized in that: Janus II, a blackbody gold / cuprous oxide heterostructure nanomaterial, was used for photocatalytic CO2 reduction, achieving maximum production rates of 6.575 μmol·g for CO, 1.717 μmol·g for CH4, and 7.621 μmol·g for C2H6. -1 ·h -1 .

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