Carbon-supported copper-gold alloy nano composite material as well as preparation method and application thereof

Abstract

The invention relates to a preparation method of a carbon-loaded copper-gold alloy nano composite material, which comprises the following steps: dispersing HAuCl4, Cu (OAc) 2 and a carbon nano material into a liquid containing a reducing agent to form a first solution; performing ultrasonic treatment on the first solution to obtain a second solution; centrifuging the second solution to obtain a precipitate; and washing and drying the precipitate to obtain the carbon-supported copper-gold alloy nano composite material. According to the preparation method, a first solution containing HAuCl4, Cu (OAc) 2 and a carbon nanomaterial is subjected to ultrasonic treatment, so that the HAuCl4 and the Cu (OAc) 2 are reduced into alloy particles containing Cu < + > on the surfaces by a reducing agent, the alloy particles are loaded on the carbon nanomaterial, and then roasting is performed in a reducing atmosphere, so that Au and Cu < + > are further alloyed, a stable Cu3Au1 crystal form is formed, the valence state of Cu < + > can be stabilized, and therefore, the Cu3Au1 / Cu composite material is obtained. Au has a weak oxyphilic property and can regulate and control an outer-layer electronic structure of a Cu atom, the strength of a Cu-O bond is enhanced, oxygen atom separation is avoided, and finally stable existence of a Cu < + > site under a high reduction potential can be realized.

Description

Technical Field

[0001] This application relates to the field of nanomaterials, and particularly to nanocomposites. Background Art

[0002] Electrocatalytic reduction of carbon dioxide into fuels or chemicals is a viable method for carbon recycling and utilization of renewable electricity. In the electrocatalytic reduction of CO2 in aqueous electrolytes, two competing reactions, namely water electrolysis hydrogen evolution reaction (HER) and CO2 reduction reaction (CO2RR), occur at the cathode. By adjusting the rates of catalyzing HER and CO2RR, syngas products with a suitable H2 / CO molar ratio (generally 0.5 - 3) can be obtained. Currently, the reported catalysts usually adjust the H2 / CO ratio by changing the operating potential, and then produce various raw materials for subsequent thermochemical technologies. However, this voltage-sensitive syngas product is not conducive to downstream technology use because the stability of the product composition ratio cannot be guaranteed.

[0003] Copper-based nanomaterials exhibit high tunability in the electrocatalytic water electrolysis hydrogen evolution reaction (HER) and CO2 reduction reaction (CO2RR), which can be attributed to the diversification of Cu element active sites. Research shows that zero-valent metallic Cu and cuprous oxide Cu + combined are more conducive to catalyzing CO2RR than pure metals or oxidized materials. The oxidation sites can accelerate the slow CO2 activation process, and the metallic sites are beneficial to the desorption of reaction products. However, Cu + sites are easily reduced to the metallic state at reduction potentials. This structural evolution will lead to changes in the electrocatalytic capabilities of HER and CO2RR in aqueous solutions, and the composition of the syngas products in the electrocatalytic reduction of CO2 in aqueous electrolytes is unstable. Summary of the Invention

[0004] Embodiments of this application provide a carbon-supported copper-gold alloy nanocomposite and its preparation method and application to solve the technical problem that Cu + sites are easily reduced at reduction potentials in copper-based nanomaterials.

[0005] In a first aspect, embodiments of this application provide a preparation method of a carbon-supported copper-gold alloy nanocomposite, and the method includes the following steps:

[0006] Disperse HAuCl4, Cu(OAc)2, and carbon nanomaterials into a liquid containing a reducing agent to form a first solution;

[0007] Ultrasonically treat the first solution to obtain a second solution;

[0008] Centrifuge the second solution to obtain a precipitate;

[0009] After washing and drying the precipitate, the carbon-supported copper-gold alloy nanocomposite material is obtained.

[0010] In some embodiments of the present application, the molar ratio of HAuCl4 to Cu(OAc)2 is 1:3.

[0011] In some embodiments of the present application, the nanocarbon material is any one of carbon nanoparticles, carbon nanotubes, and graphene, or any mixture of at least two of them, or a composite material formed by any combination of at least two of them.

[0012] In some embodiments of the present application, the nanocarbon material is carbon black.

[0013] In some embodiments of the present application, dispersing HAuCl4, Cu(OAc)2, and the nanocarbon material into a liquid containing a reducing agent to form a first solution includes the following steps:

[0014] Disperse HAuCl4 and Cu(OAc)2 into the liquid to obtain a precursor solution;

[0015] Add carbon black to the liquid to obtain a premixed solution;

[0016] Perform ultrasonic treatment on the premixed solution to obtain a carbon black dispersion;

[0017] Mix the carbon black dispersion with the precursor solution to obtain the first solution.

[0018] In some embodiments of the present application, the nanocarbon material is vulcan XC-72.

[0019] In some embodiments of the present application, the total weight of the metal elements in HAuCl4 and Cu(OAc)2 is 18% - 22% of the nanocarbon material.

[0020] In some embodiments of the present application, the reducing agent is ethylene glycol.

[0021] In some embodiments of the present application, the liquid is ethylene glycol.

[0022] In some embodiments of the present application, during the ultrasonic treatment, the treatment duration is 12 - 18 min, and the frequency of the ultrasonic wave is 18 - 22 kHz.

[0023] In some embodiments of the present application, the rate of the centrifugation treatment is 6000 - 10000 revolutions per minute.

[0024] In some embodiments of the present application, when washing the precipitate, the detergent used is ethanol.

[0025] In some embodiments of the present application, the washing is performed at least three times.

[0026] In some embodiments of the present application, the drying is carried out in an oven at 60 °C.

[0027] In some embodiments of the present application, the drying lasts at least 8 h.

[0028] In a second aspect, embodiments of the present application provide a carbon-supported copper-gold alloy nanocomposite, which is the carbon-supported copper-gold alloy nanocomposite prepared by the method according to any one of the embodiments in the first aspect.

[0029] In some embodiments of the present application, the carbon-supported copper-gold alloy nanocomposite includes a carbon nanomaterial and copper-gold composite nanoparticles loaded on the carbon nanomaterial, and the particle size of the copper-gold composite nanoparticles is 3-7 nm.

[0030] In a third aspect, embodiments of the present application provide an electrolytic water catalyst, which includes the copper-gold-carbon nanocomposite according to any one of the embodiments in the second aspect.

[0031] The above technical solutions provided by the embodiments of the present application have the following advantages compared with the prior art:

[0032] The preparation method of the carbon-supported copper-gold alloy nanocomposite provided by the embodiments of the present application ultrasonicates the first solution containing HAuCl4, Cu(OAc)2, and a carbon nanomaterial, so that HAuCl4 and Cu(OAc)2 are reduced by a reducing agent to form alloy particles containing Cu + on the surface, which are loaded onto the carbon nanomaterial, and then by calcining in a reducing atmosphere, Au and Cu + are further alloyed to form a stable Cu3Au1 crystal form, which can stabilize the valence state of Cu + and Au has a weak oxygen affinity, which can regulate the outer electron structure of Cu atoms, enhance the strength of the Cu-O bond, avoid the detachment of oxygen atoms, and finally enable the Cu + sites to stably exist at a high reduction potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0034] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0035] Figure 1 XRD patterns of Example 1 and Comparative Example 3 of the present application;

[0036] Figure 2 TEM image of Example 1 of the present application;

[0037] Figure 3 XPS spectrum of Example 1 of the present application;

[0038] Figure 4 In-situ Raman spectra of Example 1 and Comparative Example 1 of the present application during the electrochemical test;

[0039] Figure 5 Real-time gas chromatograms of Example 1, Comparative Example 1, and Comparative Example 2 of the present application during the electrochemical test. Detailed implementation manners

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.

[0041] Unless otherwise specifically stated, the terms used herein should be understood as having the meanings commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the technical field to which the present application belongs. In case of conflict, this specification shall prevail.

[0042] Unless otherwise specifically stated, various raw materials, reagents, instruments, and equipment used in the present application can be obtained through market purchases or can be prepared by existing methods.

[0043] In existing copper-based nanomaterials, the Cu + sites are easily reduced at the reduction potential.

[0044] The technical solution provided by the embodiment of the present application to solve the above technical problems has the following general idea:

[0045] In a first aspect, the embodiment of the present application provides a method for preparing a carbon-supported copper-gold alloy nanocomposite material, the method comprising the following steps:

[0046] S1: Disperse HAuCl4 (chloroauric acid), Cu(OAc)2 (copper acetate), and carbon nanomaterials into a liquid containing a reducing agent to form a first solution;

[0047] S2: Ultrasonically treat the first solution to obtain a second solution;

[0048] S3: Centrifuge the second solution to obtain a precipitate;

[0049] S4: After washing and drying the precipitate, the carbon-supported copper-gold alloy nanocomposite is obtained.

[0050] It should be noted that the nanocarbon materials described in this application refer to carbon materials with nanostructured architectures. The nanoscale can refer to the microscopic scale of the nanocarbon materials themselves, such as carbon nanoparticles with nanoscale diameters, carbon nanorods or carbon nanowires with nanoscale diameters, as well as common nanoscale carbon materials such as graphene and carbon nanotubes; or it can refer to carbon materials with nanoscale microscopic structures, such as carbon-based aerogels and carbon-based membranes with nanoscale pores.

[0051] Au and Cu can form a relatively stable alloy. Au has weak oxygenophilic properties, which can regulate the outer electron structure of Cu atoms, enhance the strength of the Cu-O bond, and prevent oxygen atoms from detaching, which is beneficial to stabilizing the valence state of Cu + and realizing the stable existence of Cu + sites at high reduction potentials.

[0052] Ultrasonic treatment can generate a cavitation effect, creating an instantaneous high-pressure and high-temperature environment at the microscopic scale, reducing HAuCl4 and Cu(OAc)2 to alloy particles containing Cu + on the surface by a reducing agent.

[0053] In this application, by ultrasonically treating the first solution containing HAuCl4, Cu(OAc)2, and nanocarbon materials, HAuCl4 and Cu(OAc)2 are reduced to alloy particles containing Cu + on the surface by a reducing agent and loaded onto the nanocarbon materials. Then, by calcining in a reducing atmosphere, Au and Cu + are further alloyed to form a stable Cu3Au1 crystal form, which can stabilize the valence state of Cu + and Au has weak oxygenophilic properties that can regulate the outer electron structure of Cu atoms, enhance the strength of the Cu-O bond, and prevent oxygen atoms from detaching. Finally, it can realize the stable existence of Cu + sites at high reduction potentials.

[0054] In some embodiments of this application, the molar ratio of HAuCl4 to Cu(OAc)2 is 1:3.

[0055] A molar ratio of HAuCl4 to Cu(OAc)2 of 1:3 can enable Cu + to form the Cu3Au1 crystal form as much as possible, thereby increasing its stability.

[0056] In some embodiments of the present application, the nanocarbon material is any one of carbon nanoparticles, carbon nanotubes, and graphene, or a mixed material of any at least two, or a composite material formed by any at least two composites.

[0057] As an example, the nanocarbon material may be one of carbon black, graphene powder, carbon nanotube powder, graphene-carbon nanotube composite film, and graphene-carbon black composite aerogel.

[0058] In some embodiments of the present application, the nanocarbon material is carbon black.

[0059] Carbon black is a mature commodity and is easily and uniformly dispersed into a solvent after being processed, which is beneficial to the uniform loading of Au and Cu + onto carbon black.

[0060] In some embodiments of the present application, dispersing HAuCl4, Cu(OAc)2, and the nanocarbon material into a liquid containing a reducing agent to form a first solution includes the following steps:

[0061] S11: Disperse HAuCl4 and Cu(OAc)2 into the liquid to obtain a precursor solution;

[0062] S12: Add carbon black to the liquid to obtain a premixed solution;

[0063] S13: Ultrasonically treat the premixed solution to obtain a carbon black dispersion;

[0064] S14: Mix the carbon black dispersion with the precursor solution to obtain the first solution.

[0065] Ultrasonic treatment is beneficial to the full dispersion of carbon black, but ultrasonic treatment will directly cause the reduction of HAuCl4. Therefore, after carbon black is ultrasonically treated alone, it is then mixed with the precursor solution.

[0066] In some embodiments of the present application, the nanocarbon material is vulcan XC-72.

[0067] In some embodiments of the present application, the total weight of the metal elements in HAuCl4 and Cu(OAc)2 is 18% - 22% of the nanocarbon material.

[0068] The total weight of the metal elements in HAuCl4 and Cu(OAc)2 being 18% - 22% of the nanocarbon material enables Au and Cu +The loading amount on the nano-carbon material is 8% - 12%. Its beneficial effect is that on the basis of ensuring a large loading amount and increasing the catalytic ability of the carbon-supported copper-gold alloy nano-composite material, the copper-gold composite nano-particles formed by Au and Cu + will not be too densely distributed on the nano-carbon material and are not easily agglomerated.

[0069] In some embodiments of the present application, the reducing agent is ethylene glycol.

[0070] Ethylene glycol has a relatively appropriate reducing ability, which can not only quickly reduce HAuCl4, but also prevent the size of the alloy nano-particles from being too large due to too violent reduction reaction.

[0071] In some embodiments of the present application, the liquid is ethylene glycol.

[0072] Ethylene glycol itself can be used as a solvent to disperse the precursor and the carbon nano-material. By dispersing the precursor and the carbon nano-material into ethylene glycol for reaction, copper-gold composite nano-particles with a diameter of about 6 nm can be obtained.

[0073] In some embodiments of the present application, in the ultrasonic treatment, the treatment duration is 12 - 18 min, and the frequency of the ultrasonic wave is 18 - 22 kHz.

[0074] In some embodiments of the present application, the rate of the centrifugation treatment is 6000 - 10000 revolutions per minute.

[0075] In some embodiments of the present application, when washing the precipitate, the detergent used is ethanol.

[0076] The beneficial effect of using ethanol as the detergent is to dissolve and clean the organic matter on the surface of the alloy particles.

[0077] In some embodiments of the present application, the washing is performed at least three times.

[0078] In some embodiments of the present application, the drying is carried out in an oven at 60 °C.

[0079] In some embodiments of the present application, the drying lasts at least 8 h.

[0080] In a second aspect, an embodiment of the present application provides a carbon-supported copper-gold alloy nano-composite material, which is the carbon-supported copper-gold alloy nano-composite material prepared by the method according to any one of the embodiments in the first aspect.

[0081] It is easy to understand that the carbon-supported copper-gold alloy nanocomposite is realized based on the preparation method of the carbon-supported copper-gold alloy nanocomposite described in the first aspect. The specific implementation manners of the carbon-supported copper-gold alloy nanocomposite can refer to the examples of the first aspect. Since the carbon-supported copper-gold alloy nanocomposite adopts some or all of the technical solutions of the examples of the first aspect, it has at least all the beneficial effects brought by the technical solutions of the examples of the first aspect, and will not be elaborated one by one here.

[0082] In some embodiments of the present application, the carbon-supported copper-gold alloy nanocomposite includes a carbon nanomaterial and copper-gold composite nanoparticles loaded on the carbon nanomaterial, and the particle size of the copper-gold composite nanoparticles is 3-7 nm.

[0083] In a third aspect, an embodiment of the present application provides an electrolytic water catalyst, and the electrolytic water catalyst includes the copper-gold carbon nanocomposite described in any embodiment of the second aspect.

[0084] The electrolytic water catalyst is realized based on the carbon-supported copper-gold alloy nanocomposite described in the second aspect. The specific implementation manners of the electrolytic water catalyst can refer to the examples of the second aspect. Since the electrolytic water catalyst adopts some or all of the technical solutions of the examples of the second aspect, it has at least all the beneficial effects brought by the technical solutions of the above examples, and will not be elaborated one by one here.

[0085] The following further elaborates the present application in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present application and not to limit the scope of the present application. The experimental methods without specific conditions noted in the following examples are usually determined according to national standards. If there is no corresponding national standard, they are carried out according to general international standards, conventional conditions, or conditions recommended by the manufacturer.

[0086] Example 1

[0087] This example provides a carbon-supported copper-gold alloy nanocomposite, and the carbon-supported copper-gold alloy nanocomposite is prepared by the following steps:

[0088] Sa: Dissolve 0.0045 mmol of HAuCl4 and Cu(OAc)2 each in 10 mL of ethylene glycol, stir for 30 minutes after mixing to obtain solution A;

[0089] Sb: Dissolve 0.024 g of Vulcan XC-72 carbon support in 10 mL of ethylene glycol, and ultrasonically treat it at room temperature for 30 minutes in an ultrasonic cleaner to obtain solution B;

[0090] Sc: Mix solution A and solution B in a 100 mL beaker to obtain solution C;

[0091] Sd: The beaker containing solution C was placed in an ultrasonic processor. A cylindrical ultrasonic probe with a diameter of 1.5 cm was placed 1 cm below the liquid level in the beaker for mixing. The top of the probe was located at the middle position of the solution. The total ultrasonic time was 10 minutes, with a 2 - second rest every 10 seconds of operation. The ultrasonic processor worked at a power of 1200 watts and a frequency of 20 kHz. After ultrasonic treatment, solution D was obtained;

[0092] Se: Solution D was centrifuged at 8000 revolutions per minute to obtain a precipitate;

[0093] Sf: The precipitate was added to 50 mL of ethanol and shaken and washed three times, and then dried in a vacuum drying oven at 50 °C for 3 hours to obtain the carbon - supported copper - gold alloy nanocomposite.

[0094] Example 2

[0095] The difference between this example and Example 1 is only that:

[0096] Step Sb is: 0.024 g of graphene powder was dissolved in 10 mL of ethylene glycol and ultrasonically treated at room temperature for 30 minutes in an ultrasonic cleaner to obtain solution B.

[0097] Specifically as follows:

[0098] This example provides a carbon - supported copper - gold alloy nanocomposite, and the carbon - supported copper - gold alloy nanocomposite is prepared by the following steps:

[0099] Sa: 0.0045 mmol of each of HAuCl4 and Cu(OAc)2 was dissolved in 10 mL of ethylene glycol, and after mixing, it was stirred for 30 minutes to obtain solution A;

[0100] Sb: 0.024 g of graphene powder was dissolved in 10 mL of ethylene glycol and ultrasonically treated at room temperature for 30 minutes in an ultrasonic cleaner to obtain solution B;

[0101] Sc: Solution A and solution B were mixed in a 100 - mL beaker to obtain solution C;

[0102] Sd: The beaker containing solution C was placed in an ultrasonic processor. A cylindrical ultrasonic probe with a diameter of 1.5 cm was placed 1 cm below the liquid level in the beaker for mixing. The top of the probe was located at the middle position of the solution. The total ultrasonic time was 10 minutes, with a 2 - second rest every 10 seconds of operation. The ultrasonic processor worked at a power of 1200 watts and a frequency of 20 kHz. After ultrasonic treatment, solution D was obtained;

[0103] Se: Solution D was centrifuged at 8000 revolutions per minute to obtain a precipitate;

[0104] Sf: The precipitate was added to 50 mL of ethanol and washed three times by shaking, and then dried in a vacuum drying oven at 50 °C for 3 hours to obtain the carbon-supported copper-gold alloy nanocomposite material.

[0105] Example 3

[0106] The difference between this example and Example 1 is only that:

[0107] Step Sb: 0.024 g of multi-walled carbon nanotubes was dissolved in 10 mL of ethylene glycol and ultrasonically treated at room temperature for 30 minutes in an ultrasonic cleaner to obtain Solution B.

[0108] Specifically as follows:

[0109] This example provides a carbon-supported copper-gold alloy nanocomposite material, and the carbon-supported copper-gold alloy nanocomposite material is prepared by the following steps:

[0110] Sa: 0.0045 mmol of HAuCl4 and Cu(OAc)2 were each dissolved in 10 mL of ethylene glycol, and after mixing, stirred for 30 minutes to obtain Solution A;

[0111] Sb: 0.024 g of multi-walled carbon nanotubes was dissolved in 10 mL of ethylene glycol and ultrasonically treated at room temperature for 30 minutes in an ultrasonic cleaner to obtain Solution B;

[0112] Sc: Solution A and Solution B were mixed in a 100 mL beaker to obtain Solution C;

[0113] Sd: The beaker containing Solution C was placed in an ultrasonic processor, a cylindrical ultrasonic probe with a diameter of 1.5 cm was placed 1 cm below the mixed liquid level in the beaker, and the top of the probe was located at the middle position of the solution. The total ultrasonic time was 10 minutes, with a 2-second rest every 10 seconds of work. The power of the ultrasonic processor was 1200 watts and the frequency was 20 kHz. After ultrasonic treatment, Solution D was obtained;

[0114] Se: Solution D was centrifuged at 8000 revolutions per minute to obtain a precipitate;

[0115] Sf: The precipitate was added to 50 mL of ethanol and washed three times by shaking, and then dried in a vacuum drying oven at 50 °C for 3 hours to obtain the carbon-supported copper-gold alloy nanocomposite material.

[0116] Example 4

[0117] The difference between this example and Example 1 is only that:

[0118] Step Sb: 0.012 g of graphene powder and 0.012 g of multi-walled carbon nanotubes were dissolved in 10 mL of ethylene glycol and ultrasonically treated at room temperature for 30 minutes in an ultrasonic cleaner to obtain Solution B.

[0119] Specifically as follows:

[0120] This embodiment provides a carbon-supported copper-gold alloy nanocomposite, and the carbon-supported copper-gold alloy nanocomposite is prepared by the following steps:

[0121] Sa: Dissolve 0.0045 mmol each of HAuCl4 and Cu(OAc)2 in 10 mL of ethylene glycol, stir for 30 minutes after mixing to obtain solution A;

[0122] Sb: Dissolve 0.012 g of graphene powder and 0.012 g of multi-walled carbon nanotubes in 10 mL of ethylene glycol, and perform ultrasonic treatment at room temperature for 30 minutes in an ultrasonic cleaner to obtain solution B;

[0123] Sc: Mix solution A and solution B in a 100 mL beaker to obtain solution C;

[0124] Sd: Place the beaker containing solution C in an ultrasonic processor, place a cylindrical ultrasonic probe with a diameter of 1.5 cm 1 cm below the liquid level of the mixture in the beaker, with the top of the probe located in the middle of the solution, the total ultrasonic time is 10 minutes, rest for 2 seconds every 10 seconds of work, the power of the ultrasonic processor is 1200 watts and the frequency is 20 kHz, and solution D is obtained after ultrasonic treatment;

[0125] Se: Centrifuge solution D at 8000 revolutions per minute to obtain a precipitate;

[0126] Sf: Add the precipitate to 50 mL of ethanol, shake and wash three times, and then dry in a vacuum drying oven at 50 °C for 3 hours to obtain the carbon-supported copper-gold alloy nanocomposite.

[0127] Comparative Example 1

[0128] The difference between this comparative example and Example 1 is only that:

[0129] Step Sa is: Dissolve 0.0045 mmol of Cu(OAc)2 in 10 mL of ethylene glycol, stir for 30 minutes after mixing to obtain solution A.

[0130] Specifically as follows:

[0131] This comparative example provides a copper-carbon composite nanomaterial, and the carbon-supported copper-gold alloy nanocomposite is prepared by the following steps:

[0132] Sa: Dissolve 0.0045 mmol of Cu(OAc)2 in 10 mL of ethylene glycol, stir for 30 minutes after mixing to obtain solution A;

[0133] Sb: Dissolve 0.024 g of Vulcan XC-72 carbon support in 10 mL of ethylene glycol, and ultrasonically treat it at room temperature for 30 minutes in an ultrasonic cleaner to obtain Solution B;

[0134] Sc: Mix Solution A and Solution B in a 100 mL beaker to obtain Solution C;

[0135] Sd: Place the beaker containing Solution C in an ultrasonic processor. Put a cylindrical ultrasonic probe with a diameter of 1.5 cm 1 cm below the liquid level of the mixture in the beaker, with the top of the probe in the middle of the solution. The total ultrasonic time is 10 minutes, with a 2-second break every 10 seconds of operation. The power of the ultrasonic processor is 1200 watts and the frequency is 20 kHz. After ultrasonic treatment, obtain Solution D;

[0136] Se: Centrifuge Solution D at 8000 revolutions per minute to obtain a precipitate;

[0137] Sf: Add the precipitate to 50 mL of ethanol and shake it three times for washing, then dry it in a vacuum drying oven at 50 °C for 3 hours to obtain the copper-carbon composite nanomaterial.

[0138] Comparative Example 2

[0139] The difference between this comparative example and Example 1 is only that:

[0140] Step Sa is: Dissolve 0.0045 mmol of HAuCl4 in 10 mL of ethylene glycol, mix and stir for 30 minutes to obtain Solution A.

[0141] Specifically as follows:

[0142] This comparative example provides a copper-carbon composite nanomaterial, and the carbon-supported copper-gold alloy nanocomposite material is prepared through the following steps:

[0143] Sa: Dissolve 0.0045 mmol of HAuCl4 in 10 mL of ethylene glycol, mix and stir for 30 minutes to obtain Solution A;

[0144] Sb: Dissolve 0.024 g of Vulcan XC-72 carbon support in 10 mL of ethylene glycol, and ultrasonically treat it at room temperature for 30 minutes in an ultrasonic cleaner to obtain Solution B;

[0145] Sc: Mix Solution A and Solution B in a 100 mL beaker to obtain Solution C;

[0146] Sd: The beaker containing solution C was placed in an ultrasonic processor. A cylindrical ultrasonic probe with a diameter of 1.5 cm was placed 1 cm below the liquid level in the beaker for mixing, and the top of the probe was located in the middle of the solution. The total ultrasonic time was 10 minutes, with a 2 - second rest every 10 seconds of operation. The ultrasonic processor worked at a power of 1200 watts and a frequency of 20 kHz. After ultrasonic treatment, solution D was obtained;

[0147] Se: Solution D was centrifuged at 8000 revolutions per minute to obtain a precipitate;

[0148] Sf: The precipitate was added to 50 mL of ethanol and washed by shaking three times, and then dried in a vacuum drying oven at 50 °C for 3 hours to obtain the gold - carbon composite nanomaterial.

[0149] Comparative Example 3

[0150] The copper - gold - carbon nanocomposite obtained in Example 1 was calcined in an atmosphere of a mixed gas of H2 and N2 at 300 °C for 2 hours to obtain a deoxidized copper - gold - carbon nanocomposite.

[0151] Related experiments and effect data:

[0152] The carbon - supported copper - gold alloy nanocomposite obtained in Example 1 and the deoxidized copper - gold - carbon nanocomposite obtained in Comparative Example 3 were tested by X - ray diffraction (XRD). The results are shown in Figure 1 .

[0153] It is Figure 1 easily found that the carbon - supported copper - gold alloy nanocomposite obtained in Example 1 and the deoxidized copper - gold - carbon nanocomposite obtained in Comparative Example 3 showed a set of crystal forms without peak splitting. This proves that the synthesized materials are homogeneous materials rather than heterogeneous structures.

[0154] The carbon - supported copper - gold alloy nanocomposite obtained in Example 1 was tested by transmission electron microscopy (TEM). The results are shown in Figure 2 .

[0155] Observation Figure 2 shows that the particle size of the copper - gold composite nanoparticles is mainly distributed in the range of 3 - 6 nm, and the morphology is uniform.

[0156] The carbon - supported copper - gold alloy nanocomposite in Example 1 was tested by X - ray photoelectron spectroscopy (XPS). The results are as Figure 3 .

[0157] Among them Figure 3 the left figure in the middle is the XPS graph of the carbon - supported copper - gold alloy nanocomposite in the range of 555 - 585 eV; Figure 3 the right figure in the middle is the XPS graph of the carbon - supported copper - gold alloy nanocomposite in the range of 527 - 537 eV.

[0158] It isFigure 3 As can be easily seen from the left middle figure, in the carbon-supported copper-gold alloy nanocomposite, Cu atoms exhibit +1 and 0 valence states. From Figure 3 As can be easily seen from the right middle figure, in the range of 527 - 537 eV, the XPS spectrum of the carbon-supported copper-gold alloy nanocomposite highly coincides with the XPS spectrum of the O element, indicating that the carbon-supported copper-gold alloy nanocomposite contains lattice oxygen. XPS analyzes the surface information of the carbon-supported copper-gold alloy nanocomposite. Combining with the XRD results, it is judged that there is a small amount of Cu2O on the surface of the carbon-supported copper-gold alloy nanocomposite, and its main body is the Cu3Au1 crystal.

[0159] Electrochemical tests were carried out on the copper-gold-carbon nanocomposite obtained in Example 1, the copper-carbon nanocomposite obtained in Comparative Example 1, and the gold-carbon nanocomposite obtained in Comparative Example 2. Specifically:

[0160] The CO2RR reaction was carried out in an electrochemical workstation using a standard three-electrode system, with Ag / AgCl(4M KCl) as the reference electrode and a platinum wire as the counter electrode. The test was carried out in an H-type glass cell, with 100 mL of 0.5 M KHCO3 aqueous solution on both sides as the electrolyte. Before each measurement, the electrolyte was purged with CO2 at a rate of 25 sccm min-1 for 20 minutes, and the CO2 flow rate was 5 sccm min-1 after the test started. The RHE potential was calculated by the formula E(RHE) = E(Ag / AgCl) + 0.0591×pH + 0.21 V.

[0161] The method for fabricating the test electrode is as follows: 5 mg of the catalytic material (the catalytic material is the copper-gold-carbon nanocomposite obtained in Example 1 or the copper-carbon nanocomposite obtained in Comparative Example 1) is dissolved in 920 μL of ethanol, and then 80 μL of Nafion is added. After ultrasonic treatment for 20 minutes, 100 μL of the suspension is vertically dropped onto a 1 cm×1 cm hydrophobic carbon paper with a pipette, and 100 μL of the suspension is vertically dropped onto the other side of the hydrophobic carbon paper, and then it is allowed to air dry naturally in the air. The gas products are analyzed in real time by a gas chromatograph equipped with a flame ionization detector and a thermal conductivity detector, and the carrier gas is ultra-high purity argon.

[0162] Figure 4 It is the in-situ Raman spectrum measured during the electrochemical test. By Figure 4 It is found that as the reduction voltage increases, the diffraction peak of the Cu-O bond exhibited by the carbon-supported copper-gold alloy nanocomposite obtained in Example 1 has not weakened, while the diffraction peak of the copper-carbon composite nanomaterial synthesized by the same method in Comparative Example 1 gradually decreases to disappear, indicating that the CuAu alloy structure can protect the Cu-O bond from being broken and can protect the Cu + sites from being reduced.

[0163] During the electrochemical test, the products of electrocatalytic CO2RR were also analyzed in real time by gas chromatography. Figure 5 It is the gas chromatogram obtained.

[0164] By Figure 5 It was found that the catalytic performances of the copper-gold-carbon nanocomposite obtained in Example 1, the copper-carbon nanocomposite obtained in Comparative Example 1, and the gold-carbon nanocomposite obtained in Comparative Example 2 were significantly different under non-electrified conditions. The copper-gold-carbon nanocomposite obtained in Example 1 could stably catalyze the conversion of CO2 into syngas products with an H2 / CO molar ratio of about 1 / 1 at a wide potential, while neither Comparative Example 1 nor Comparative Example 2 could maintain stability.

[0165] In summary, this application uses an ultrasonic-assisted liquid-phase chemical reduction method to synthesize a copper-gold-carbon nanocomposite containing oxygen atoms. Through the analysis of X-ray diffraction patterns, transmission electron microscope images, X-ray photoelectron spectroscopy, etc. of the synthesized materials, it is proved that Cu + exists. Through in-situ Raman characterization, it was found that even at -0.9V vs. RHE, there was no sign of a decrease in the peak intensity of Cu + in the copper-gold-carbon nanocomposite, while the peak intensity of Cu + in the copper-carbon nanocomposite decreased or even disappeared, proving the feasibility of stabilizing the Cu + active sites in the alloy structure. This CuAu alloy nanocatalyst anchored with oxygen atoms has excellent catalytic activity and stability in a neutral solution (0.5M KHCO3), and can stably and efficiently catalyze the HER and CO2RR reactions at a potential of -0.5 to -0.9V vs. RHE, obtaining syngas products with a component ratio basically stable at H2:CO = 1:1.

[0166] The various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be construed as a rigid limitation on the scope of this application; therefore, it should be considered that the described range description has specifically disclosed all possible sub-ranges and single values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within that range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0167] In this application, unless otherwise specified, the orientation terms such as "upper" and "lower" specifically refer to the drawing directions in the attached drawings. Additionally, in the description of the specification of this application, the terms "comprise", "include", etc. mean "include but not limited to". Moreover, the term "comprise", "include" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, the elements defined by the statement "comprising..." do not exclude the presence of additional identical elements in the process, method, article or device comprising said elements. In this document, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. In this document, "and / or" describes the associated relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, or B exists alone. For the associated relationship of more than three associated objects described by "and / or", it means that these three associated objects can exist alone for any one of them, or any at least two of them exist simultaneously. For example, for A, and / or B, and / or C, it can represent that any one of A, B, and C exists alone, or any two of them exist simultaneously, or all three of them exist simultaneously. In this document, "at least one" means one or more, and "multiple" means two or more. "At least one kind", "at least one item (piece) below" or similar expressions refer to any combination of these items, including any combination of single item (piece) or plural items (pieces). For example, "at least one item (piece) among a, b, or c", or, "at least one item (piece) among a, b, and c" can both represent: a, b, c, a - b (i.e., a and b), a - c, b - c, or a - b - c, where a, b, and c can be single or multiple respectively.

[0168] The above are only specific embodiments of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application will not be limited to these embodiments shown herein, but rather will conform to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A preparation method of a carbon-supported copper-gold alloy nanocomposite, characterized in that, The method includes the following steps: Disperse HAuCl4, Cu(OAc)2, and carbon nanomaterials into a liquid containing a reducing agent to form a first solution; Perform ultrasonic treatment on the first solution to obtain a second solution; Centrifuge the second solution to obtain a precipitate; After washing and drying the precipitate, obtain the carbon-supported copper-gold alloy nanocomposite material.

2. The preparation method of the carbon-supported copper-gold alloy nanocomposite material according to claim 1, characterized in that, The molar ratio of HAuCl4 to Cu(OAc)2 is 1:

3.

3. The preparation method of the carbon-supported copper-gold alloy nanocomposite according to claim 1, characterized in that, The nanocarbon material is any one of carbon nanoparticles, carbon nanotubes, graphene, or a mixed material of any at least two of them, or a composite material formed by any at least two of them combined.

4. The preparation method of the carbon-supported copper-gold alloy nanocomposite according to claim 1, wherein The nanocarbon material is carbon black.

5. The preparation method of the carbon-supported copper-gold alloy nanocomposite according to claim 4, characterized in that, The step of dispersing HAuCl4, Cu(OAc)2, and carbon nanomaterials into a liquid containing a reducing agent to form a first solution includes the following steps: Disperse HAuCl4 and Cu(OAc)2 into the liquid to obtain a precursor solution; Add carbon black to the liquid to obtain a premixed solution; Perform ultrasonic treatment on the premixed solution to obtain a carbon black dispersion; Mix the carbon black dispersion with the precursor solution to obtain the first solution.

6. The preparation method of the carbon-supported copper-gold alloy nanocomposite according to claim 4, wherein The nanocarbon material is vulcan XC-72.

7. The preparation method of the carbon-supported copper-gold alloy nanocomposite according to claim 1, wherein, The total weight of the metal elements in HAuCl4 and Cu(OAc)2 is 18% - 22% of the nanocarbon material.

8. The preparation method of the carbon-supported copper-gold alloy nanocomposite according to claim 1, characterized in that, The reducing agent is ethylene glycol.

9. The preparation method of the carbon-supported copper-gold alloy nanocomposite material according to claim 8, characterized in that, The liquid is ethylene glycol.

10. The preparation method of the carbon-supported copper-gold alloy nanocomposite according to claim 1, wherein, In the ultrasonic treatment, the treatment duration is 12 - 18 min, and the frequency of the ultrasonic wave is 18 - 22 kHz.

11. The preparation method of the carbon-supported copper-gold alloy nanocomposite according to claim 1, wherein, The rate of the centrifugation treatment is 6000 - 10000 revolutions per minute.

12. The preparation method of the carbon-supported copper-gold alloy nanocomposite material according to claim 1, characterized in that, When washing the precipitate, the detergent used is ethanol.

13. The preparation method of the carbon-supported copper-gold alloy nanocomposite according to claim 1, characterized in that, The washing is performed at least three times.

14. The preparation method of the carbon-supported copper-gold alloy nanocomposite according to claim 1, wherein, The drying is carried out in an oven at 60°C.

15. The preparation method of the carbon-supported copper-gold alloy nanocomposite according to claim 14, wherein, The drying lasts at least 8 h.

16. A carbon-supported copper-gold alloy nanocomposite, characterized in that, The carbon-supported copper-gold alloy nanocomposite material is the carbon-supported copper-gold alloy nanocomposite material prepared by the method according to any one of claims 1 - 15.

17. The carbon-supported copper-gold alloy nanocomposite according to claim 16, wherein, The carbon-supported copper-gold alloy nanocomposite material includes carbon nanomaterials and copper-gold composite nanoparticles supported on the carbon nanomaterials, and the particle size of the copper-gold composite nanoparticles is 3 - 7 nm.

18. An electrolyzed water catalyst, characterized in that, The electrolytic water catalyst includes the copper-gold-carbon nanocomposite according to claim 16 or claim 17.

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