Cu3P / three-dimensional graphene composite catalyst as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of catalysts, and provides a Cu3P / three-dimensional graphene composite catalyst as well as a preparation method and application thereof. The composite catalyst comprises a substrate (foam metal), graphene deposited on the substrate, and Cu3P nanoparticles deposited on the graphene. The foam metal is used as a substrate, the graphene is deposited on the foam metal, and the graphene has excellent stability, so that the stability of the composite catalyst can be improved; the Cu3P nano particles can provide abundant reaction sites; meanwhile, the electron transfer rate can be increased through the interface interaction between Cu3P and graphene. The embodiment shows that the composite catalyst disclosed by the invention shows excellent HER activity of 73mV under the condition of 1M KOH and the condition of 10mA / cm < 2 >. More importantly, the composite catalyst also shows excellent durability (gt; 90 hours) under the hydrogen evolution condition of 1M KOH.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and particularly relates to a Cu 3 P / three-dimensional graphene composite catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] Hydrogen is considered to be the most promising new clean energy source because of its environmental friendliness and high combustion calorific value. In recent years, electrocatalytic water splitting for hydrogen production has attracted much research attention due to its low cost and high hydrogen production purity. Therefore, many researchers are committed to preparing high-performance catalysts as active materials for electrochemical water splitting. So far, noble metal-based materials are considered to be the most promising electrocatalysts for hydrogen evolution reaction (HER) because of their good electrical conductivity and excellent catalytic performance. However, their high price and low crustal reserves greatly limit their commercial applications. Therefore, it is very important to develop high-performance and low-cost catalysts.

[0003] So far, many functional materials, including metal sulfides, metal-organic frameworks, two-dimensional layered materials, etc., have been developed as efficient electrocatalytic water splitting hydrogen production catalysts. However, the catalytic activity of the above functional materials still needs to be improved. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a Cu 3 P / three-dimensional graphene composite catalyst, a preparation method thereof, and an application thereof. The Cu 3 P / three-dimensional graphene composite catalyst provided by the present invention has excellent catalytic activity.

[0005] In order to achieve the above invention purpose, the present invention provides the following technical solutions: The present invention provides a Cu 3 P / three-dimensional graphene composite catalyst, including a substrate, graphene deposited on the substrate, and Cu 3 P nanoparticles deposited on the graphene; the substrate is a foam metal.

[0006] Preferably, the foam metal includes nickel foam.

[0007] Preferably, the thickness of the graphene is 5-30 nm, and the particle size of the Cu 3 P nanoparticles is 300-500 nm.

[0008] The present invention also provides a preparation method of the Cu 3 P / three-dimensional graphene composite catalyst according to the above technical solution, including the following steps: Preparing graphene on the substrate by chemical vapor deposition to obtain a first precursor; Copper is deposited on the first precursor by electrochemically atomic deposition to obtain a second precursor; The second precursor and a phosphating agent are mixed and subjected to phosphating to obtain the Cu 3 P / three-dimensional graphene composite catalyst.

[0009] Preferably, the parameters of the chemical vapor deposition include: the working gas is methane, the flow rate of the working gas is 10-30 sccm, the gauge pressure of the working pressure is 5×10 -2 ~10×10 -2 Pa, and the time is 1-2 h.

[0010] Preferably, the parameters of the electrochemically atomic deposition include: the current density is 5-15 mA / cm 2 , the concentration of the copper ion aqueous solution is 0.1-0.5 mol / L, and the deposition time is 20-40 min.

[0011] Preferably, the phosphating agent includes NaH 2 PO 2 .

[0012] Preferably, the mass ratio of the second precursor to the phosphating agent is 1:1-5.

[0013] Preferably, the temperature of the phosphating is 300-400 °C, the heating rate to the temperature of the phosphating is 2-5 °C / min, the time of the phosphating is 1-3 h, and the phosphating is carried out under a protective atmosphere.

[0014] The present invention also provides the application of the Cu 3 P / three-dimensional graphene composite catalyst described in the above technical solution or the Cu 3 P / three-dimensional graphene composite catalyst prepared by the preparation method described in the above technical solution in the field of electrocatalytic water splitting for hydrogen production.

[0015] The present invention provides a Cu3P / three-dimensional graphene composite catalyst.

[0016] The Cu 3 P / three-dimensional graphene composite catalyst (hereinafter referred to as the composite catalyst) of the present invention uses a foam metal as a substrate, and graphene is deposited on the foam metal. The obtained graphene has excellent stability and can improve the stability of the composite catalyst; Cu 3 P nanoparticles can provide rich reaction sites; at the same time, the interfacial interaction between Cu 3 P nanoparticles and graphene can promote the electron transfer rate. The data of the examples show that: the composite catalyst of the present invention under the condition of 1 M KOH, at 10 mA / cm 2Under the conditions, it shows excellent HER activity of 73 mV. Importantly, the composite catalyst also exhibits excellent durability (>90 h) under hydrogen evolution conditions in 1 M KOH. This fully demonstrates that the composite catalyst of the present invention is an excellent candidate for high-performance HER electrocatalysts.

[0017] The present invention also provides the Cu 3 P / three-dimensional graphene composite catalyst preparation method. In the present invention, graphene is prepared by chemical vapor deposition, and then copper is deposited by atomic deposition; phosphorization is carried out in the presence of a phosphorizing agent to obtain Cu 3 P nanoparticles. The preparation method provided by the present invention successfully prepares the Cu 3 P / three-dimensional graphene composite catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 FIG. is a flow chart of the preparation method of the Cu 3 P / three-dimensional graphene composite catalyst provided by the present invention; Figure 2 FIG. is a scanning electron microscope of different materials; Figure 3 FIG. is the SEM image of Cu 3 P-Gr-2 at different magnification ratios; Figure 4 FIG. is the TEM and HRTEM images of Cu 3 P-Gr-2; Figure 5 FIG. is the TEM image and corresponding element distribution map of Cu 3 P-Gr-2; Figure 6 FIG. is the XRD spectra of Cu 3 P-Gr-2, Cu 3 P and Ni foam; Figure 7 FIG. is the XPS spectra of Gr, Cu 3 P and Cu 3 P-Gr-2; Figure 8 FIG. is the linear sweep voltammetry (LSV) curves of different materials corrected by iR; Figure 9 FIG. is the Tafel slopes of different materials; Figure 10 FIG. is the electrochemical impedance spectroscopy (EIS) diagrams of different materials; Figure 11 FIG. is the CV curve of Cu 3 P-Gr-2; Figure 12 FIG. is the electrochemical double layer capacitance (Cdl) of different materials; Figure 13 is Cu 3 (Electrochemical cycling stability diagram of P-Gr-2.) Detailed implementation manners

[0019] The present invention provides a Cu 3 P / three-dimensional graphene composite catalyst, including a substrate, graphene deposited on the substrate, and Cu 3 P nanoparticles deposited on the graphene; the substrate is a foam metal.

[0020] The Cu 3 P / three-dimensional graphene composite catalyst provided by the present invention includes a substrate, the substrate is a foam metal, and the foam metal preferably includes nickel foam. The Cu 3 P / three-dimensional graphene composite catalyst of the present invention uses a foam metal as a substrate, which can enable the graphene deposited on the above substrate to have a three-dimensional structure, providing more sites for the loading of Cu 3 P nanoparticles. At the same time, the high stability of graphene can improve the structural stability of the Cu 3 P / three-dimensional graphene composite catalyst; at the same time, the foam metal can conduct electricity, thereby promoting the electron transfer rate and improving the catalytic activity.

[0021] The Cu 3 P / three-dimensional graphene composite catalyst provided by the present invention includes graphene deposited on the substrate, and the thickness of the graphene is preferably 5-30 nm, specifically preferably 5 nm, 10 nm, 15 nm, 20 nm, 25 nm or 30 nm.

[0022] The Cu 3 P / three-dimensional graphene composite catalyst provided by the present invention includes Cu 3 P nanoparticles deposited on the graphene, and the particle size of the Cu 3 P nanoparticles is preferably 300-500 nm. In the present invention, the particle morphology of the Cu 3 P can provide rich reaction sites; at the same time, the interfacial interaction between the Cu 3 P nanoparticles and graphene can promote the electron transfer rate and improve the catalytic activity.

[0023] The present invention also provides a preparation method of the Cu 3 P / three-dimensional graphene composite catalyst described in the above technical solution, including the following steps: Preparing graphene on the substrate by chemical vapor deposition to obtain a first precursor; Depositing copper on the first precursor by electrochemical atomic deposition to obtain a second precursor; Mix the second precursor and the phosphating agent and perform phosphating to obtain the Cu 3 P / three-dimensional graphene composite catalyst.

[0024] Figure 1 The Cu 3 P / three-dimensional graphene composite catalyst provided by the present invention is shown in the flowchart of the preparation method. The preparation method of the present invention will be described in detail below in conjunction with Figure 1 the present invention.

[0025] The present invention uses chemical vapor deposition to prepare graphene on the substrate to obtain a first precursor, denoted as Ni-Gr composite.

[0026] In the present invention, the substrate is preferably pretreated before use. The pretreatment preferably includes: pickling, washing with water, washing with alcohol, and drying in sequence. In the present invention, the reagent for pickling is preferably an inorganic acid, the inorganic acid is preferably sulfuric acid, and the concentration of the sulfuric acid is preferably 0.5 mol / L; the pickling is preferably carried out under ultrasonic conditions, and the pickling time is preferably 20-40 min, specifically preferably 30 min. In the present invention, the reagent for washing with water is preferably deionized water, and the washing with water is preferably carried out under ultrasonic conditions, and the washing time with water is preferably 20-40 min, specifically preferably 20 min, 30 min or 40 min. In the present invention, the reagent for washing with alcohol is preferably ethanol, and more preferably absolute ethanol; the washing with alcohol is preferably carried out under ultrasonic conditions, and the washing time with alcohol is preferably 20-40 min, specifically preferably 20 min, 30 min or 40 min. The present invention does not make specific limitations on the drying, as long as it can be dried.

[0027] In the present invention, the parameters of the chemical vapor deposition include: the working gas is preferably methane, and the flow rate of the working gas is preferably 10-30 sccm, specifically preferably 10 sccm, 15 sccm, 20 sccm, 25 sccm or 30 sccm; the gauge pressure of the working pressure is preferably 5×10 -2 ~10×10 -2 Pa, and the time is preferably 1-2 h, specifically preferably 1 h, 1.5 h or 2 h.

[0028] In the present invention, graphene with a three-dimensional structure is formed on the substrate by chemical vapor deposition. Graphene can improve the stability of the catalyst. At the same time, graphene with a three-dimensional structure can provide more sites for the loading of Cu 3 P nanoparticles.

[0029] After obtaining the first precursor, the present invention uses electrochemical atomic deposition to deposit copper on the first precursor to obtain a second precursor, denoted as Cu-Gr-Ni composite.

[0030] In the present invention, the parameters of the electrochemical atomic deposition include: the current density is preferably 5-15 mA / cm 2 , specifically preferably 5 mA / cm 2 , 10 mA / cm 2 or 15 mA / cm 2 ; the concentration of the copper ion aqueous solution is preferably 0.1-0.5 mol / L, specifically preferably 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L or 0.5 mol / L; the deposition time is preferably 20-40 min, specifically preferably 20 min, 30 min or 40 min. In the present invention, the copper ions in the copper ion aqueous solution are preferably provided by one or more of copper chloride, copper nitrate and copper acetate, and further preferably provided by copper nitrate.

[0031] In the present invention, the deposition thickness of copper in the second precursor is preferably 5-20 nm, specifically preferably 5 nm, 10 nm, 15 nm or 20 nm.

[0032] The present invention uses electrochemical atomic deposition to deposit copper on the first precursor, and the deposition of copper provides sites for the formation of Cu 3 P.

[0033] After obtaining the second precursor, the present invention mixes the second precursor and a phosphating agent for phosphating to obtain the Cu 3 P / three-dimensional graphene composite catalyst, denoted as Cu 3 P-Gr composite.

[0034] In the present invention, the phosphating agent preferably includes NaH 2 PO 2 .

[0035] In the present invention, the mass ratio of the second precursor to the phosphating agent is preferably 1:1-5, specifically preferably 1:1, 1:2, 1:3, 1:4 or 1:5.

[0036] In the present invention, the temperature of the phosphating is preferably 300-400 °C, specifically preferably 300 °C, 350 °C or 400 °C; the heating rate for raising the temperature to the phosphating temperature is preferably 2-5 °C / min, specifically preferably 2 °C / min, 3 °C / min, 4 °C / min or 5 °C / min; the time of the phosphating is preferably 1-3 h, specifically preferably 1 h, 2 h or 3 h, and the phosphating is preferably carried out under a protective atmosphere, and the protective atmosphere is preferably nitrogen.

[0037] In the present invention, the phosphidation is preferably carried out in a tubular furnace. Along the gas flow direction of the protective atmosphere, the phosphidating agent is placed upstream of the tubular furnace, and the second precursor is placed downstream of the tubular furnace.

[0038] In the present invention, the phosphidation can cause the atomically deposited copper to form Cu 3 P nanoparticles.

[0039] The present invention also provides the application of the Cu 3 P / three-dimensional graphene composite catalyst described in the above technical solution or the Cu 3 P / three-dimensional graphene composite catalyst prepared by the preparation method described in the above technical solution in the field of electrocatalytic water splitting for hydrogen production.

[0040] The present invention does not specifically limit the application mode of the Cu 3 P / three-dimensional graphene composite catalyst, and those skilled in the art can set it according to actual needs.

[0041] The following combines examples to elaborate in detail on the Cu 3 P / three-dimensional graphene composite catalyst provided by the present invention, its preparation method and application, but they cannot be understood as limiting the protection scope of the present invention.

[0042] Example The nickel foam (purchased from Suzhou Keshenghe Metal Materials Co., Ltd., with a thickness of 1 mm) was successively ultrasonically cleaned with 0.5 mol / L sulfuric acid, deionized water and absolute ethanol for 30 min each, and then dried for standby.

[0043] Graphene was grown on the nickel foam using chemical vapor deposition. The specific parameters included: the working gas was methane, the flow rate of methane was 20 sccm, the gauge pressure of the working pressure was 8×10 -2 Pa, and the time was 1 h to obtain the first precursor, denoted as the Ni-Gr composite, wherein the growth thickness of the graphene was 15 nm.

[0044] Copper was deposited on the surface of the first precursor using electrochemical atomic deposition. The specific parameters included: the current density was 10 mA / cm 2 , the concentration of the copper nitrate aqueous solution was 0.2 mol / L, and the deposition time was 30 min to obtain the second precursor, denoted as the Cu-Gr-Ni composite, wherein the deposition thickness of copper was 10 nm.

[0045] The second precursor and NaH 2 PO 2Weigh according to a mass ratio of 1:2 and perform phosphating in a nitrogen atmosphere in a tube furnace. The temperature of phosphating is 300 °C (heating rate: 2 °C / min), and the time is 2 h. Along the flow direction of nitrogen, the phosphating agent is placed upstream of the tube furnace, and the second precursor is placed downstream of the tube furnace. After cooling to room temperature, Cu 3 P / three-dimensional graphene composite catalyst is obtained, denoted as Cu 3 P-Gr-1 composite.

[0046] Change the phosphating temperatures to 350 °C and 400 °C respectively to obtain Cu 3 P-Gr-2 composite and Cu 3 P-Gr-3 composite respectively.

[0047] Figure 2 are scanning electron microscopes of different materials. Among them, the left picture in the upper row is the scanning electron microscope image of nickel foam, the right picture in the upper row is the scanning electron microscope image of the first precursor, and the lower row is the scanning electron microscope image of Cu 3 P-Gr-2. It can be seen from Figure 2 that compared with nickel foam, after graphene grows on nickel foam, the surface of the first precursor becomes rough, which will provide a large number of growth sites for Cu 3 P. It can be seen from the scanning electron microscope image of Cu 3 P-Gr-2 that Cu 3 P nanoparticles have successfully grown on nickel foam.

[0048] Figure 3 are SEM images of Cu 3 P-Gr-2 at different magnifications. It can be seen from Figure 3 that Cu 3 P nanoparticles are evenly distributed on graphene; the size of Cu 3 P nanoparticles is between 300 and 500 nm.

[0049] Figure 4 are the TEM and HRTEM images of Cu 3 P-Gr-2. Among them, the left picture in the upper row is the TEM image of Cu 3 P-Gr-2, the right picture in the upper row is the HRTEM image of Cu 3 P-Gr-2, and the inset in the right picture in the upper row is the selected area electron diffraction (SAED) image of Cu 3 P; the lower row of pictures is the magnified HRTEM image. Figure 4 The TEM image of 3The nanoparticle morphology of P; the HRTEM image shows a uniform lattice distribution, indicating its high quality; the SAED image confirms its single-crystal structure; the magnified HRTEM image shows a lattice distance of 0.205 nm, corresponding to Cu 3 The (300) plane of P.

[0050] Figure 5 is Cu 3 The TEM image and corresponding elemental distribution map of P-Gr-2, Figure 5 showing uniform distribution of P and Cu elements.

[0051] Figure 6 is Cu 3 P-Gr-2 (corresponding to Figure 6 the Cu in 3 P-Gr), Cu 3 XRD patterns of P and Ni foam, from Figure 6 which it can be seen that: the peaks located at 44.52°, 51.86° and 77.06° correspond to Ni foam (JCPDS No.04-0850). The peaks located at 45.35° and 52.58° match the (300) and (220) planes of Cu 3 P (JCPDS No.02-1263). By comparison, it is found that after Cu 3 P grows on Ni foam, the (220) peak of Ni foam shifts, indicating that Cu 3 P has been successfully decorated on the surface of Ni foam.

[0052] The surface chemical compositions of different materials were characterized by X-ray photoelectron spectroscopy (XPS), and the results are as Figure 7 shown, Figure 7 for the XPS spectra of Gr, Cu 3 P and Cu 3 P-Gr-2 (corresponding to the Cu in the figure 3 P-Gr), among which, (a) is the XPS spectrum of Cu 3 P and Cu 3 P-Gr-2 (corresponding to the Cu in the figure 3 P-Gr) for Cu 2p, (b) is the XPS spectrum of Cu 3 P and Cu 3 P-Gr-2 (corresponding to the Cu in the figure 3 P-Gr) for P 2p, (c) is the XPS spectrum of Gr and Cu 3 P-Gr-2 (corresponding to the Cu in the figure 3 P-Gr) for C 1s. From Figure 7 the (a) of which it can be seen that: the Cu 2p of Cu 3 P3 / 2 and Cu 2p 1 / 2 are located at 931.30 and 951.25 eV respectively. From Figure 7 (b) of 3 it can be seen that the P 2p peak in Cu Figure 7 P is located at 132.69 eV. From 3 (c) of 3 it can be seen that the XPS spectrum of C 1s in Gr shows that the C=C, C-O and C-O-H bonds are located at 283.49, 284.95 and 287.22 eV respectively. In contrast, the Cu

[0053] Electrocatalytic hydrogen evolution performance of the synthesized samples was tested by a three-electrode system.

[0054] Figure 8 are the linear sweep voltammetry (LSV) curves corrected for iR of different materials. From Figure 8 it can be seen that the catalytic performance of Cu 3 P-Gr-2 is 73 mV at 10 mA / cm 2 , which is lower than that of nickel foam (435 mV), Gr (340 mV), Cu 3 P (232 mV), Cu 3 P-Gr-1 (140 mV) and Cu 3 P-Gr-3 (105 mV). The excellent electrocatalytic hydrogen evolution activity of Cu 3 P-Gr-2 may be due to the following reasons: 1) Gr can improve the conductivity of the sample; 2) Cu 3 P nanoparticles can provide multiple reaction sites; 3) The interfacial interaction between Cu 3 P and Gr can promote the electron transfer rate during the HER process. In particular, the HER activity of the prepared Cu 3 P-Gr-2 is also smaller than that reported previously, indicating that Cu 3 P-Gr is a promising electrocatalyst for hydrogen evolution.

[0055] Figure 9 are the Tafel slopes of different materials. From Figure 9 it can be seen that the Tafel slope of Cu 3 P-Gr-2 is 98 mV / dec, which is much smaller than that of Cu 3 P-Gr-1 (149 mV / dec), Cu 3 P-Gr-3 (146 mV / dec), Cu 3P (187 mV / dec) and Gr (260 mV / dec). Cu 3 P-Gr-2 has a lower Tafel slope, indicating a faster reaction kinetics during the HER process. Generally, hydrogen generation occurs in three stepwise reactions: H 2 O + M + e − → M-H ad + OH − (Volmer step, 120 mV / dec) H 2 O + M-H ads + e − → H 2 + M + OH − (Heyrovsky step, 40 mV / dec) 2M-H ads → H 2 + 2M (Tafel step, 30 mV / dec) Cu 3 The Tafel slope of Cu P-Gr-2 is as high as 98 mV / dec, indicating the existence of the Volmer-Heyrovsky process during hydrogen evolution.

[0056] Figure 10 are the electrochemical impedance spectroscopy (EIS) diagrams of different materials. It can be seen from Figure 10 that: Cu 3 The charge transfer resistance of Cu P-Gr-2 (5.9 Ω) is lower than that of nickel foam (33.7 Ω), Gr (31.3 Ω), Cu 3 P (26.7 Ω), Cu 3 P-Gr-1 (20.8 Ω) and Cu 3 P-Gr-3 (11.5 Ω), indicating its excellent charge transfer ability.

[0057] Figure 11 are the CV curves of Cu 3 P-Gr-2. It can be seen from Figure 11 that: at different scan rates, its CV curves show regular changes, proving its good electrochemical characteristics.

[0058] The electrochemical double-layer capacitance (Cdl) was obtained using CV data. The results are as Figure 12 shown. Figure 12 are the electrochemical double-layer capacitances (Cdl) of different materials. As Figure 12 shown, Gr, Cu 3 P, Cu 3 P-Gr-1, Cu 3 P-Gr-2 and Cu3 The Cdl values of P-Gr-3 are 1.2, 2.5, 3.3, 7.6, and 5.1 mF / cm respectively 2 . In particular, compared with other samples, Cu 3 P-Gr-2 exhibits a higher Cdl, indicating that it can provide more active sites during the hydrogen production process.

[0059] The electrocatalytic cycle stability of Cu 3 P-Gr-2 was tested under different conditions, and the results are as Figure 13 shown Figure 13 For the electrocatalytic cycle stability diagram of Cu 3 P-Gr-2, as Figure 13 shown, after more than 90 h of testing, Cu 3 P-Gr-2 still exhibits excellent HER catalytic performance. The SEM and XPS of Cu 3 P-Gr-2 were measured after the cyclic test. Compared with before the cycle, the morphology of Cu 3 P-Gr-2 is similar, indicating its structural stability. The XPS results show that during the cyclic durability test, the O 1s peak can be detected, indicating that Cu 3 P-Gr-2 has undergone an oxidation process. These results indicate that Cu 3 P-Gr-2 has excellent cyclic durability for HER, which may be due to: 1) The growth of graphene Gr on nickel foam may result in a solid structure of Gr-Ni foam; 2) The heterojunction interface constructed between Gr and Cu 3 P can improve the durability of the structure; 3) The strong interfacial reaction between Gr and Cu 3 P can greatly improve the charge transfer rate between the electrode and the electrolyte.

[0060] The present invention successfully grows Cu 3 P nanoparticles on graphene, and the synthesized Cu 3 P / three-dimensional graphene composite catalyst (Cu 3 P-Gr) exhibits excellent HER activity of 73 mV at 10 mA / cm 2 under the condition of 1 M KOH. Importantly, this Cu 3 P / three-dimensional graphene composite catalyst also exhibits excellent durability (>90 h) under the hydrogen evolution conditions of 1 M KOH. Its excellent catalytic performance is mainly attributed to: 1) The nanoparticle morphology of Cu 3 P can provide abundant reaction sites; 2) The excellent conductivity and stability of Gr can enhance the conductivity and structural stability of the sample; 3) Cu 3The interfacial interaction effect between P and Gr can promote the charge transfer ability. The research results of the present invention show that Cu 3 P / three-dimensional graphene composite catalyst is an excellent candidate for high-performance HER electrocatalyst.

[0061] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A Cu3P / three-dimensional graphene composite catalyst, characterized in that: It comprises a substrate, graphene deposited on the substrate, and Cu3P nanoparticles deposited on the graphene; the substrate is foam metal.

2. The Cu3P / three-dimensional graphene composite catalyst according to claim 1, characterized in that: The foam metal includes foamed nickel.

3. The Cu3P / three-dimensional graphene composite catalyst according to claim 1, characterized in that The thickness of the graphene is 5-30 nm, and the particle size of the Cu3P nanoparticles is 300-500 nm.

4. The method for preparing the Cu3P / three-dimensional graphene composite catalyst according to any one of claims 1 to 3, characterized in that: The following steps are involved: preparing graphene on the substrate by chemical vapor deposition to obtain a first precursor; Depositing copper on the first precursor by electrochemical atomic deposition to obtain a second precursor; The second precursor and the phosphating agent are mixed and phosphated to obtain the Cu3P / three-dimensional graphene composite catalyst.

5. The preparation method according to claim 4, characterized in that: The parameters of the chemical vapor deposition include: the working gas is methane, the flow rate of the working gas is 10-30 sccm, the gauge pressure of the working pressure is 5×10 -2 ~10×10 -2 Pa, time is 1~2h.

6. The preparation method according to claim 4, characterized in that: The parameters of the electrochemical atomic deposition include: current density of 5-15 mA / cm 2 The concentration of the copper ion aqueous solution is 0.1~0.5mol / L, and the deposition time is 20~40min.

7. The preparation method according to claim 4, characterized in that: The phosphating agent includes NaH2PO2.

8. The preparation method according to claim 4 or 7, characterized in that: The mass ratio of the second precursor to the phosphating agent is 1:1-5.

9. The preparation method according to claim 4 or 7, characterized in that: The phosphating temperature is 300-400° C., the heating rate to the phosphating temperature is 2-5° C. / min, the phosphating time is 1-3 hours, and the phosphating is carried out under a protective atmosphere.

10. Use of the Cu3P / three-dimensional graphene composite catalyst according to any one of claims 1 to 3 or the Cu3P / three-dimensional graphene composite catalyst prepared by the preparation method according to any one of claims 4 to 9 in the field of electrocatalytic water splitting to produce hydrogen.

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