CN114570390A - Preparation method of thin-layer oxygen-containing graphite alkyne-coated metal composite catalyst - Google Patents

Abstract

The invention belongs to the technical field of energy materials, and in particular relates to a preparation method of a thin-layer oxygen-containing graphdiyne-coated metal composite catalyst. In the present invention, an oxidizing agent is used to oxidize the end-alkyne of the graphdiyne to obtain the graphdiyne oxide, and then the graphdiyne oxide is mixed with an alkaline solution. , lose the proton and become -O ^-ion , further make the interlayer of graphdiyne peel off due to electrostatic repulsion, obtain thin-layer oxygen-containing graphene dispersion liquid, and finally use thin-layer oxygen-containing graphene dispersion liquid as electrolyte, and use metal compound As a working electrode, an electrochemical reduction reaction is carried out. Under the action of current, part of the oxygen functional groups of the thin layer of oxygen-containing graphyne get electrons and are reduced, thereby reducing its solubility and adsorbing on the surface of the electrode (metal compound nanosheets), resulting in excellent performance. The catalytic activity and stability of thin-layer oxygen-containing graphdiyne-coated metal composite catalysts.

Description

A kind of preparation method of thin-layer oxygen-containing graphdiyne-coated metal composite catalyst

technical field

The invention belongs to the technical field of energy materials, and in particular relates to a preparation method of a thin-layer oxygen-containing graphdiyne-coated metal composite catalyst.

Background technique

A carbon-coated catalyst is a catalyst that coats a carbon layer on the surface of a metal active phase. The carbon-coated catalyst utilizes the stability of the carbon layer to effectively prevent the oxidation, decomposition or corrosion of the metal phase in the electrochemical process, thereby improving the stability of the catalyst. The catalytic activity of carbon-coated catalysts depends on the penetration of electrons from the inner metal phase to the outer carbon layer. Therefore, the thickness of the carbon layer is a key factor affecting its catalytic activity. At present, new catalysts using transition metal carbides, oxides, phosphides, and selenides as inner metal phases and N-doped carbon, graphene, and carbon nanotubes as coating layers all show excellent catalytic activity and stability. sex. However, carbon-coated catalysts still have problems such as uncontrollable type and amount of heteroatom doping, unclear active sites on the catalyst surface, and difficult synthesis of thin carbon shells.

Graphdiyne (GDY) is a new all-carbon nanostructure material after fullerenes, carbon nanotubes and graphene. The unique atomic arrangement of graphyne makes it rich in carbon chemical bonds, high π-conjugation, wide interplanar spacing, natural band gap, excellent stability, excellent electron-ion conductivity, and low temperature on any substrate surface. The nature of controllable growth has changed the harsh preparation methods of traditional carbon materials, and has shown great advantages and advancements in synthesis and performance regulation.

Based on the unique electronic, topological and preparation advantages of graphdiyne, graphdiyne is considered to be an excellent choice as a shell carbon material for encapsulated catalysts. The research group of Academician Li Yuliang used self-supporting MoS ₂ (Hui L, Xue Y, He F, et al Efficient hydrogen generation on graphdiyne-based heterostructure. NanoEnergy, 2019, 55, 135-142), NiO (Yu H, Xue Y, Hui L, et al Graphdiyne-engineeredheterostructures for efficient overall water-splitting.Nano Energy,2019,64,103928), CoN _x (Fang Y,Xue Y,Hui L,et al In situ growth of graphdiyne basedheterostructure:toward efficient overall water splitting.Nano Energy, 2019, 59, 591-597) or hydroxide (Hui L, Jia D, Yu H, et al Ultrathin graphdiyne-wrapped ironcarbonate hydroxide nanosheets toward efficient water splitting. ACS appliedmaterials&interfaces, 2018, 11(3), 2618-2625) A graphyne-coated catalyst was prepared by in-situ growth of a graphyne layer on the surface of the nano-array with the advantage that it can grow on any substrate. Based on the strong interfacial interaction between graphdiyne and metal compounds and the protective effect of the outer layer of graphdiyne, the obtained catalyst obtained excellent catalytic activity and stability. However, due to the van der Waals force and π-π interaction force, the graphene layers are easy to stack and superimpose. Too thick graphene layers will lead to poor conductivity of the catalyst, and the electrons in the inner metal phase cannot penetrate into the surface layer of the graphene, which will cause the catalyst to lack active sites. Moreover, the all-carbon hydrophobic surface of graphdiyne also limits the catalytic process of hydrophilic and gas-repellent, which ultimately leads to poor catalytic activity of the catalyst, which is a key scientific problem restricting the construction of efficient and stable graphdiyne-coated catalysts.

SUMMARY OF THE INVENTION

In view of this, the object of the present invention is to provide a method for preparing a thin-layer oxygen-containing graphene-coated metal composite catalyst, and the thin-layer oxygen-containing graphene-coated metal composite catalyst prepared by the method solves the problem of using graphdiyne to prepare In the process of graphdiyne-coated catalyst, the thick graphdiyne layer and the hydrophobic surface inhibit the catalytic activity of the catalyst.

In order to achieve the above object, the present invention provides the following technical solutions:

The invention provides a preparation method of a thin-layer oxygen-containing graphdiyne-coated metal composite catalyst, comprising the following steps:

Mixing the graphdiyne powder and the oxidant, and oxidizing to obtain the graphdiyne oxide;

Mixing the graphdiyne oxide and the alkaline solution, and peeling off to obtain a thin-layer oxygen-containing graphdiyne dispersion;

A three-electrode system using the thin-layer oxygen-containing graphene dispersion solution as an electrolyte and a metal compound nanosheet as a working electrode is used to carry out an electrochemical reduction reaction to obtain a thin-layer oxygen-containing graphene-coated metal composite catalyst;

The thickness of the thin-layer oxygen-containing graphyne in the thin-layer oxygen-containing graphene-coated metal composite catalyst is less than 3 nm.

Preferably, the oxidant includes one or more of sulfuric acid, nitric acid, potassium permanganate, potassium perchlorate and hydrogen peroxide; the oxidant is used as an oxidant solution, the mass of the graphdiyne powder and the volume of the oxidant solution The ratio is (1-10) g:400 mL; the mass concentration of the oxidant solution is preferably >60%.

Preferably, the oxidation is carried out under ultrasonic conditions, the power of the ultrasonic is 100-400W, and the oxidation time is 1-48h.

Preferably, the alkaline solution includes potassium hydroxide solution; the concentration of the potassium hydroxide solution is 1 mol/L; the ratio of the mass of the graphyne oxide to the volume of the alkaline solution is 5 mg:(0.015～0.05 )mL.

Preferably, the peeling time is 30 min; the peeling is ultrasonic peeling.

Preferably, the mass concentration of the thin-layer oxygen-containing graphyne in the thin-layer oxygen-containing graphene dispersion liquid is 0.05-0.5 mg/mL.

Preferably, the electrochemical reduction reaction is carried out by potentiostatic method, cyclic voltammetry or linear sweep voltammetry.

Preferably, in the potentiostatic method, the potentiostat is -0.9-1.5V vs. Ag/AgCl, and the time for the redox reaction is 0.5-30 min.

Preferably, in the cyclic voltammetry, the voltage range is -1.5-0.5V, the number of scan cycles is 1-20 cycles, and the scan rate is 5-100mV/s.

Preferably, in the linear sweep voltammetry, the voltage range is 0-1.5V, and the scanning rate is 5-100mV/s.

The invention provides a method for preparing a thin-layer oxygen-containing graphyne-coated metal composite catalyst, which comprises the following steps: mixing graphyne powder and an oxidant, and oxidizing to obtain graphyne oxide; Alkaline solutions are mixed and peeled off to obtain a thin-layer oxygen-containing graphene dispersion; an electrochemical reduction is carried out by using the thin-layer oxygen-containing graphene dispersion as an electrolyte and a three-electrode system with metal compound nanosheets as a working electrode. reaction to obtain a thin-layer oxygen-containing graphyne-coated metal composite catalyst.

In the present invention, an oxidizing agent is used to oxidize the graphyne terminal alkyne into oxygen-containing functional groups (such as carboxyl group, aldehyde group and hydroxyl group) to obtain the graphyne oxide, and then the graphyne oxide is mixed with an alkaline solution, and in the alkaline solution, The oxygen-containing functional groups of graphyne (such as -COOH or -OH, etc.) lose protons and become -O ^- ions, so that the layers of graphyne are peeled off due to electrostatic repulsion, and a thin layer of oxygen-containing graphene dispersion is obtained. The graphdiyne dispersion is the electrolyte, the metal compound is used as the working electrode, and the electrochemical reduction reaction is carried out. Under the action of the current, part of the oxygen functional groups of the thin-layer oxygen-containing graphyne get electrons and are reduced, lose oxygen atoms, and increase the oxygen-containing thin layer. The hydrophobicity of the surface of graphyne further reduces its solubility, so that it is adsorbed on the surface of the electrode (metal compound nanosheet) to obtain a thin layer of oxygen-containing graphene-coated metal composite catalyst. Layer structure, the active site of the metal compound will not be covered by the oxygen-containing coating layer and lose its catalytic activity, and the inner metal phase electrons can easily penetrate to the surface of the graphyne to activate carbon atoms to form new active sites, thereby solving the problem of The in situ grown graphdiyne layer is thick, which makes the catalyst lack active sites and reduces its catalytic activity. In addition, the surface of the thin-layer oxygen-containing graphdiyne coating layer provided by the present invention still has residual oxygen functional groups, and compared with the all-carbon hydrophobic surface of graphyne, the surface of the thin-layer oxygen-containing graphyne coating layer has enhanced hydrophilicity, The limitation of the all-carbon hydrophobic surface of graphdiyne on the catalytic process of hydrophilic and gas-repellent is solved, and the catalytic activity of the thin-layer oxygen-containing graphdiyne-coated metal composite catalyst is improved. The results of the examples show that the thin-layer oxygen-containing graphdiyne-coated metal composite catalyst prepared by the present invention has excellent catalytic activity and stability.

Description of drawings

Fig. 1 is the TEM image of graphdiyne, graphdiyne oxide and exfoliated graphdiyne oxide in alkaline solution in Example 1;

Fig. 2 is the SEM image of CoP and CoP@RGDYO in embodiment 1;

Figure 3 is the SEM image of CoP@GDY in Comparative Example 1;

Fig. 4 is the electrocatalytic hydrogen evolution activity and stability test chart of CoP, CoP@RGDYO in Example 1 and CoP@GDY in Comparative Example 1 in 1.0M KOH solution and 0.5MH ₂ SO ₄ solution;

Fig. 5 is the SEM image of MoS ₂ and MoS ₂ @RGDYO in Example 2;

Fig. 6 is the SEM image of NiCo ₂ S ₄ and r-GDYO/NiCo ₂ S ₄ in Example 3;

7 is a graph showing the GCD curve and cycle stability of NiCo ₂ S ₄ and r-GDYO/NiCo ₂ S ₄ in Example 3 at a current density of 30 mA cm ⁻² ;

FIG. 8 is a graph of the static water contact angle of the surfaces of GDY, GDYO and RGDYO in Example 1. FIG.

Detailed ways

The invention provides a preparation method of a thin-layer oxygen-containing graphdiyne-coated metal composite catalyst, comprising the following steps:

Mixing the graphdiyne powder and the oxidant, and oxidizing to obtain the graphdiyne oxide;

Mixing the graphdiyne oxide and the alkaline solution, and peeling off to obtain a thin-layer oxygen-containing graphdiyne dispersion;

A three-electrode system with the thin-layer oxygen-containing graphene dispersion liquid as electrolyte and metal compound nanosheets as working electrodes is used for electrochemical reduction reaction to obtain a thin-layer oxygen-containing graphene-coated metal composite catalyst.

Unless otherwise specified, the present invention has no special requirements on the source of the raw materials used for the preparation, and commercially available products well known to those skilled in the art can be used.

In the present invention, the graphdiyne powder and the oxidant are mixed and oxidized to obtain the graphdiyne oxide.

In the present invention, the source of the graphdiyne powder is not particularly limited, and the graphdiyne powder well-known in the art can be used. In an embodiment of the present invention, the graphdiyne powder is specifically according to the method of Li Yuliang's research group (Li G, Li Y, LiuH, et al. Architecture of graphdiyne nanoscale films [J]. Chemical Communications, 2010, 46(19): 3256-3258) prepared graphdiyne powder, the specific preparation method includes the following steps: under nitrogen protection, slowly drop 50 mL of pyridine solution containing hexaalkynylbenzene (HEB) into pyridine (25 mL) containing copper foil, at 110 ° C React for 3 days. The graphdiyne on the surface of the Cu foil was exfoliated by hot DMF solution ultrasonically, the powder was washed with 4M NaOH, 6M HCl and 4M NaOH under reflux successively, and the product was collected after centrifugation and drying.

In the embodiment of the present invention, the graphdiyne powder is specifically obtained according to the prior art (Zhou J, Gao X, LiuR, et al. Synthesis of graphdiyne nanowalls using acetylenic coupling reaction [J]. Journal of the American Chemical Society, 2015 , 137(24):7596-7599) prepared graphdiyne powder, the specific preparation method includes the following steps: under nitrogen protection, slowly drop 50mL of acetone solution containing hexaalkynylbenzene (HEB) (20mg) into an appropriate amount of In the mixed solution of acetone, pyridine and TMEDA (volume ratio of 100:5:1) of copper foil (completed within 2 to 3 hours), react at 50 °C for 12 hours in the dark. After the reaction is completed, the graphite on the surface of the Cu foil The alkyne was ultrasonically stripped by hot DMF solution, the powder was washed with 4M NaOH, 6M HCl and 4M NaOH under reflux successively, and the product was collected after centrifugation and drying.

In the present invention, the oxidizing agent preferably includes one or more of sulfuric acid, nitric acid, potassium permanganate, potassium perchlorate and hydrogen peroxide, more preferably sulfuric acid and nitric acid; the oxidizing agent is used as an oxidizing agent solution; When the oxidant is sulfuric acid and nitric acid, the volume ratio of the sulfuric acid solution and the nitric acid solution is preferably 1:(1-3), more preferably 1:1; the mass concentration of the oxidant solution is preferably >60%, and the sulfuric acid The mass concentration of the solution is preferably 98%, and the mass concentration of the nitric acid solution is preferably 68%. When the oxidants are the above-mentioned types, the present invention does not specifically limit the proportions of different types of oxidants, and any proportion can be used.

In the present invention, the ratio of the mass of the graphdiyne powder to the volume of the oxidant is preferably (1-10) g:400 mL, more preferably (5-10) g:400 mL.

The present invention does not specifically limit the mixing process of the graphdiyne powder and the oxidant, and a mixing process well known in the art may be used.

In the present invention, the oxidation time is preferably 1-48h, more preferably 2-10h; the oxidation is preferably carried out under ultrasonic conditions; the ultrasonic power is preferably 100-400W, more preferably 100-300W .

After the oxidation is completed, in the present invention, the product obtained from the oxidation is preferably diluted, filtered, washed and dried in sequence to obtain the graphdiyne oxide. In the present invention, the dilution method is to add water for dilution; the present invention does not specifically limit the amount of water used for the dilution, which can be adjusted according to actual needs. In the present invention, the filtering method is preferably suction filtering with a sand core funnel. The process of the suction filtration is not particularly limited in the present invention, and a suction filtration process well known in the art can be used. In the present invention, the solution used in the washing is water; in the present invention, it is preferable to wash until the product obtained by the oxidation is neutral. The present invention does not specifically limit the drying process, and a drying process well known in the art can be used.

The present invention oxidizes the graphyne by using an oxidant to oxidize the terminal alkyne of the graphyne to obtain the graphyne oxide.

After the graphdiyne oxide is obtained, the present invention mixes the graphdiyne oxide with an alkaline solution and exfoliates to obtain a thin-layer oxygen-containing graphdiyne dispersion.

In the present invention, the alkaline solution preferably includes potassium hydroxide solution; the concentration of the potassium hydroxide solution is preferably 1 mol/L; the ratio of the mass of the graphyne oxide to the volume of the alkaline solution is preferably 5 mg : (0.015-0.05) mL, more preferably 5 mg: (0.015-0.04) mL.

In the present invention, the process of mixing the graphdiyne oxide and the alkaline solution is preferably mixing the graphdiyne oxide and water, and then adding the alkaline solution.

In the present invention, the ratio of the mass of the graphdiyne oxide to the volume of water is preferably 5 mg:(10-30) mL, more preferably 5 mg:(10-25) mL.

In the present invention, the peeling time is preferably 30 min; the peeling method is preferably ultrasonic; the power of the ultrasonic is preferably 100-400W, more preferably 100-300W.

In an alkaline solution, the oxygen-containing functional groups of graphyne, such as -COOH or -OH, lose protons and become -O ^- ions, which further exfoliate the graphene layers due to electrostatic repulsion, resulting in a thin layer of oxygen-containing graphene dispersion. liquid.

After obtaining the thin-layer oxygen-containing graphene dispersion liquid, the present invention uses the thin-layer oxygen-containing graphene dispersion liquid as an electrolyte and a three-electrode system with metal compound nanosheets as a working electrode to carry out an electrochemical reduction reaction to obtain a thin layer Oxygenated graphdiyne-coated metal composite catalysts.

In the present invention, the three-electrode system preferably uses the Ag/AgCl electrode as the reference electrode and the Pt electrode as the counter electrode.

In the present invention, the concentration of the thin-layer oxygen-containing graphyne in the thin-layer oxygen-containing graphyne dispersion liquid is 0.05-0.5 mg/mL, more preferably 0.1-0.5 mg/mL.

In the present invention, the metal compound is preferably metal oxide, metal hydroxide, metal sulfide, metal phosphide or metal carbide; the metal oxide is preferably NiO, Co ₃ O ₄ , RuO ₂ ; The metal hydroxide is preferably Co(OH) ₂ , NiFe-LDH or CoFe-LDH; the metal sulfide is preferably MoS ₂ , NiCo ₂ S ₄ or SnS ₂ , more preferably MoS ₂ or NiCo ₂ S ₄ ; The metal phosphide is preferably _CoXP , _MoXP , or FeP, more preferably CoP; the metal carbide is preferably MoC or FeC.

In the present invention, the metal compound nanosheets are preferably metal compound nanosheets with a supporting material; the supporting material is preferably carbon cloth, foamed nickel, foamed copper, foamed iron or copper foil in any form, more preferably Carbon cloth, nickel foam or copper foam.

The present invention preferably adopts potentiostatic method, cyclic voltammetry or linear sweep voltammetry to carry out the electrochemical reduction reaction.

In the present invention, in the potentiostatic method, the potentiostat is preferably -0.9 to -1.5V vs. Ag/AgCl, more preferably -1.2V vs. Ag/AgCl, and the time of the redox reaction is preferably 0.5 ~30min, more preferably 1~5min.

In the present invention, in the cyclic voltammetry, the voltage range is preferably -1.5~0.5Vvs.Ag/AgCl, more preferably -1.5~0Vvs.Ag/AgCl, and the number of scan turns is preferably 1~20 turns, more It is preferably 10 cycles, and the scan rate is preferably 5 to 100 mV/s.

In the present invention, in the linear sweep voltammetry, the voltage range is preferably 0-1.5V, and the scanning rate is preferably 5-100mV/s.

Under the action of electric current, part of the oxygen functional groups of the thin layer of oxygen-containing graphyne gain electrons and lose oxygen atoms, which increases the hydrophobicity of the surface of the thin layer of oxygen-containing graphyne and reduces its solubility, making it adsorb on the electrode (metal compound nanosheets) The surface of the metal compound is coated on the surface of the metal compound to obtain a thin layer of oxygen-containing graphdiyne-coated metal composite catalyst.

Since the oxygen-containing graphene coating is a thin layer structure, the active sites of the metal compounds will not be covered by the oxygen-containing coating and lose catalytic activity, and the inner metal phase electrons can easily penetrate to the surface of the graphene. The carbon atoms are activated to form new active sites, thereby solving the problem that the catalyst lacks active sites due to the thick in-situ-grown graphdiyne layer, thereby reducing its catalytic activity. In addition, the surface of the thin-layer oxygen-containing graphdiyne coating layer provided by the present invention still has residual oxygen functional groups, and the hydrophilicity of the surface of the thin-layer oxygen-containing graphene coating layer is enhanced compared with the all-carbon hydrophobic surface of the graphyne layer. , which solves the limitation of the all-carbon hydrophobic surface of graphyne on the catalytic process of hydrophilic and gas-repellent, and improves the catalytic activity of the thin-layer oxygen-containing graphyne-coated metal composite catalyst.

The thin-layer oxygen-containing graphdiyne-coated metal composite catalyst prepared by the preparation method provided by the invention can be used in catalyst materials, batteries, electrode materials and sensor materials.

The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention.

Example 1

According to the method of Li Yuliang's research group (Li G, Li Y, Liu H, et al. Architecture of graphdiyneanoscale films [J]. Chemical Communications, 2010, 46(19): 3256-3258), graphdiyne powder (GDY) was prepared;

Put 30 mg of the graphdiyne powder into a mixed solution of 2 mL of a sulfuric acid solution with a mass concentration of 98% and 2 mL of a nitric acid solution with a mass concentration of 68%, sonicated at 100W for 2 hours, and then diluted with water, and filtered with a sand core funnel. , and washed with water and suction-filtered the product to neutrality and then dried to obtain graphdiyne oxide (GDYO);

5 mg of the graphdiyne oxide was added to 25 mL of deionized water, 0.015 mL of 1M KOH solution was added dropwise, and sonicated at 100 W for 30 min to obtain a thin-layer oxygen-containing graphdiyne dispersion (0.2 mg/mL);

The thin-layer oxygen-containing graphdiyne dispersion is used as the electrolyte, the cobalt phosphide (CoP) nanosheet supported by carbon cloth is used as the working electrode, the Ag/AgCl electrode is used as the reference electrode, and the Pt electrode is used as the counter electrode. The electrochemical reduction reaction of vs. Ag/AgCl was carried out at a constant potential for 1 min to obtain a thin-layer oxygen-containing graphyne-coated CoP composite catalyst (CoP@RGDYO).

Example 2

According to the prior art (Zhou J, Gao X, Liu R, et al. Synthesis of graphdiynenanowalls using acetylenic coupling reaction[J]. Journal of the American Chemical Society, 2015, 137(24):7596-7599) prepared graphdiyne powder ;

Put 50 mg of the graphdiyne powder into a mixed solution of 2 mL of sulfuric acid solution with a mass concentration of 98% and 2 mL of a nitric acid solution with a mass concentration of 68%, sonicated at 100W for 2 hours, and then diluted with water, and filtered with a sand core funnel. , and the product is washed with water and suction-filtered to neutrality and then dried to obtain graphdiyne oxide;

5 mg of the graphdiyne oxide was added to 25 mL of deionized water, 0.015 mL of a 1 M KOH solution was added dropwise, and sonicated at 100 W for 30 min to obtain a thin-layer oxygen-containing graphdiyne dispersion (0.2 mg/mL);

Using the thin-layer oxygen-containing graphdiyne dispersion as electrolyte, MoS ₂ nanosheets supported by carbon cloth as working electrode, Ag/AgCl electrode as reference electrode, Pt electrode as counter electrode, at 0～-1.5V vs. The Ag/AgCl voltage interval was tested for 10 cycles, and a thin-layer oxygen-containing graphdiyne-coated MoS ₂ composite catalyst (MoS ₂ @RGDYO) was obtained.

Example 3

According to the prior art (Zhou J, Gao X, Liu R, et al. Synthesis of graphdiynenanowalls using acetylenic coupling reaction[J]. Journal of the American Chemical Society, 2015, 137(24):7596-7599) prepared graphdiyne powder ;

Put 50 mg of the graphdiyne powder into a mixed solution of 2 mL of sulfuric acid solution with a mass concentration of 98% and 2 mL of a nitric acid solution with a mass concentration of 68%, sonicated at 100W for 2 hours, and then diluted with water, and filtered with a sand core funnel. , and the product is washed with water and suction-filtered to neutrality and then dried to obtain graphdiyne oxide;

5 mg of the graphdiyne oxide was added to 25 mL of deionized water, 0.015 mL of 1M KOH solution was added dropwise, and sonicated at 100 W for 30 min to obtain a thin-layer oxygen-containing graphdiyne dispersion (0.2 mg/mL);

Using the thin-layer oxygen-containing graphdiyne dispersion as electrolyte, NiCo ₂ S ₄ nanosheets supported by carbon cloth as working electrode, Ag/AgCl electrode as reference electrode, Pt electrode as counter electrode, at -1.2V vs. The electrochemical reduction reaction was carried out under the constant potential of Ag/AgCl for 5 min, and a thin-layer oxygen-containing graphdiyne-coated NiCo ₂ S ₄ composite catalyst (NiCo ₂ S ₄ @RGDYO) was obtained.

Comparative Example 1

Under nitrogen protection, 50 mL of acetone solution containing HEB (15 mg) was slowly dropped into the mixed solution of acetone, pyridine and TMEDA (volume ratio of 100:5:1) with appropriate amount of copper foil and carbon cloth loaded with CoP (2 ~3h), and react at 50°C for 12h in the dark. After the reaction solution was cooled, the carbon cloth was taken out and washed with acetone, hot DMF (80 °C) and acetone in turn to remove the organic solvent and oligomers on the surface, and then air-dried for later use. The product was denoted as CoP@GDY.

Performance Testing

(1) Use transmission electron microscope to detect the morphology of graphdiyne, graphdiyne oxide and graphdiyne oxide in alkaline solution in Example 1, the results are shown in Figure 1, wherein a and d are the values of Example 1 Graphdiyne, b and e are graphdiyne oxides of Example 1, c and f are graphdiyne oxides exfoliated in alkaline solution of Example 1.

It can be seen from Fig. 1 that both graphdiyne and graphdiyne oxide present a multi-layer superposition, and after ultrasonic exfoliation in an alkaline solution, the graphdiyne oxide presents a thin layer.

(2) The CoP and CoP@RGDYO in Example 1 were tested by scanning electron microscopy. The results are shown in Figure 2, where a and c are the morphological structures of CoP at the scale of 200 nm and 2 μm, respectively, and b and d are respectively are the morphological structures of CoP@RGDYO at 500 nm and 5 μm scales.

It can be seen from Figure 2 that the thin-layer graphdiyne is uniformly and tightly coated on the surface of the CoP nanosheets.

(3) Scanning electron microscopy was used to detect CoP@GDY in Comparative Example 1, and the results are shown in Figure 3.

It can be seen from Figure 3 that GDY is grown in situ on the surface of CoP, and the GDY layer is thicker.

(4) The electrocatalytic hydrogen evolution activity and stability of CoP and CoP@RGDYO in Example 1 and CoP@GDY in Comparative Example in 1.0M KOH solution and 0.5MH ₂ SO ₄ solution were tested, and the results are shown in Fig. 4 where a is the electrocatalytic hydrogen evolution activity of CoP, CoP@RGDYO and CoP@GDY in 1.0 M KOH solution, b is the electrocatalytic hydrogen evolution activity of CoP, CoP@RGDYO and CoP@GDY in 0.5 MH ₂ SO ₄ solution, c is the stability of CoP and CoP@RGDYO in 1.0 M KOH solution, and d is the stability of CoP and CoP@RGDYO in 0.5 MH ₂ SO ₄ solution.

It can be seen from a in Fig. 4 that in 1.0 M KOH solution, the required overpotentials for CoP, CoP@RGDYO and CoP@GDY are 123mV, 206mV, 86mV, 142mV, respectively, when the current density reaches 10mA cm ^-2 and 100mAcm ^-2 . and 174mV, 305mV. It can be seen from b in Fig. 3 that the overpotentials required for CoP, CoP@RGDYO and CoP@GDY are 117mV, 298mV, and 97mV, 151mV, respectively, when the current density reaches 10 and 100 mA cm ^-2 in 0.5MH ₂ SO ₄ solution. and 167mV, 341mV. It can be seen that after the CoP surface is coated with a thin layer of oxygen-containing graphdiyne, the overpotential decreases when used for the HER reaction, which is more obvious at high current density. Conversely, after in situ growth of graphdiyne on the CoP surface (CoP@GDY), its reaction overpotential increases.

It can be seen from c and d in Figure 4 that under the same overpotential (130mV in 1.0M KOH solution and 100mV in 0.5MH ₂ SO ₄ solution), when CoP is used as a catalyst, the current density rapidly drops below 10 mA cm ^-2 , and CoP@ After 100 hours of continuous reaction of RGDYO, the current density retention rate can reach more than 80%. The above results indicate that the coating of CoP nanosheets with a thin layer of oxygen-containing graphdiyne improves the electrocatalytic hydrogen evolution activity and stability of CoP.

(5) The MoS ₂ and MoS ₂ @RGDYO in Example 2 were tested by scanning electron microscopy, and the results are shown in Fig. 5, where a is the morphological structure of MoS ₂ at 200 nm scale, and b is MoS ₂ @RGDYO Morphological structure at 200 nm scale.

It can be seen from b in Fig. 5 that a thin layer of oxygen-containing graphdiyne is coated on the surface of MoS ₂ nanosheets.

(6) The NiCo ₂ S ₄ and r-GDYO/NiCo ₂ S ₄ in Example 3 were tested by scanning electron microscopy, and the results are shown in Figure 6, where a is the morphology of NiCo ₂ S ₄ at a scale of 500 nm Structure, b is the morphological structure of and r-GDYO/NiCo ₂ S ₄ at 500 nm scale.

It can be seen from b in Fig. 6 that a thin layer of oxygen-containing graphdiyne is coated on the surface of NiCo ₂ S ₄ nanosheets.

(7) The GCD curve and cycle stability of NiCo ₂ S ₄ and r-GDYO/NiCo ₂ S ₄ in Example 3 were tested at a current density of 30 mA cm ^-2 . The results are shown in Figure 7 , where a is GCD curves of NiCo ₂ S ₄ and r-GDYO/NiCo ₂ S ₄ at a current density of 30 mAcm ^-2 , b is the stability of NiCo ₂ S ₄ and r-GDYO/NiCo ₂ S ₄ at a current density of 30 mA cm ^-2 .

It can be seen from a in Figure 7 that the specific capacitances of NiCo ₂ S ₄ and r-GDYO/NiCo ₂ S ₄ are 1.57F cm ^-2 and 3.09F cm ^-2 respectively; from b in Figure 7, it can be seen that NiCo ₂ S ₄ and r The capacitance retention rates of -GDYO/NiCo ₂ S ₄ after 5000 cycles are 70.0% and 93.1%, respectively; the above results show that the specific capacitance of NiCo ₂ S ₄ is improved by coating NiCo ₂ S ₄ with thin oxygen-containing graphdiyne and cycle stability.

(8) The static contact angles of water on the surfaces of GDY, GDYO and RGDYO in Example 1 were tested, and the results are shown in FIG. 8 .

It can be seen from Fig. 8 that the presence of oxygen-containing functional groups in the thin-layer oxygen-containing graphyne (RGDYO) obtained by reduction of graphene oxide (GDYO) and graphene oxide makes the surface more hydrophilic.

Although the above embodiment has made a detailed description of the present invention, it is only a part of the embodiments of the present invention rather than all of the embodiments. People can also obtain other embodiments without creativity according to the present embodiment, and these embodiments are all It belongs to the protection scope of the present invention.

Claims (10)

1. A preparation method of a thin-layer oxygen-containing graphite alkyne-coated metal composite catalyst comprises the following steps:

mixing graphite alkyne powder with an oxidant, and oxidizing to obtain graphite alkyne oxide;

mixing the graphite alkyne oxide with an alkaline solution, and stripping to obtain a thin-layer oxygen-containing graphite alkyne dispersion liquid;

carrying out electrochemical reduction reaction by using the thin-layer oxygen-containing graphite alkyne dispersion liquid as electrolyte and a three-electrode system using a metal compound nanosheet as a working electrode to obtain a thin-layer oxygen-containing graphite alkyne-coated metal composite catalyst;

the thickness of the thin layer of oxygen-containing graphite alkyne in the thin layer of oxygen-containing graphite alkyne-coated metal composite catalyst is less than 3 nm.

2. The preparation method according to claim 1, wherein the oxidant comprises one or more of sulfuric acid, nitric acid, potassium permanganate, potassium perchlorate and hydrogen peroxide; the oxidant is used as oxidant solution, and the mass ratio of the graphite alkyne powder to the volume of the oxidant solution is (1-10) g: 400 mL; the mass concentration of the oxidant solution is preferably > 60%.

3. The preparation method according to claim 1 or 2, wherein the oxidation is carried out under ultrasonic conditions, and the power of the ultrasonic is 100-400W; the oxidation time is 1-48 h.

4. The production method according to claim 1, wherein the alkaline solution comprises a potassium hydroxide solution; the concentration of the potassium hydroxide solution is 1 mol/L; the ratio of the mass of the graphite alkyne oxide to the volume of the alkaline solution is 5mg to (0.015-0.05) mL.

5. The production method according to claim 1, wherein the time for the peeling is 30 min; the peeling is ultrasonic peeling.

6. The preparation method according to claim 1, wherein the mass concentration of the thin-layer oxygen-containing graphdiyne in the thin-layer oxygen-containing graphdiyne dispersion liquid is 0.05-0.5 mg/mL.

7. The method of claim 1, wherein the electrochemical reduction reaction is performed using potentiostatic method, cyclic voltammetry, or linear sweep voltammetry.

8. The method according to claim 7, wherein the potentiostatic method is a potentiostatic method of-0.9 to-1.5V vs. Ag/AgCl, and the time of the redox reaction is 0.5 to 30 min.

9. The method according to claim 7, wherein in the cyclic voltammetry, the voltage is in the range of-1.5 to 0.5V, the number of scanning cycles is in the range of 1 to 20 cycles, and the scanning rate is in the range of 5 to 100 mV/s.

10. The method according to claim 7, wherein in the linear sweep voltammetry, the voltage range is 0 to-1.5V, and the sweep rate is 5 to 100 mV/s.

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