Phosphorus-doped metallic nickel catalyst prepared on basis of tetrabutylphosphonium chloride / glycerol eutectic solvent and preparation method and application of phosphorus-doped metallic nickel catalyst

Abstract

The invention provides a phosphorus-doped metal nickel catalyst prepared on the basis of a tetrabutylphosphonium chloride / glycerol eutectic solvent as well as a preparation method and application of the phosphorus-doped metal nickel catalyst. The preparation method of the phosphorus-doped metallic nickel catalyst comprises the following steps: mixing tetrabutyl phosphonium chloride and glycerol at 55-120 DEG C for reaction to obtain a eutectic solvent; the method comprises the following steps: adding nickel nitrate into a deep-eutectic solvent, ultrasonically mixing uniformly, and heating; and cooling, washing and drying to obtain the phosphorus-doped metal nickel catalyst prepared on the basis of the tetrabutyl phosphonium chloride / glycerol eutectic solvent. The preparation method of the catalyst is simple, the doping process is controllable, the cost is low, and the catalytic performance of the obtained catalyst is excellent.

Description

Technical Field

[0001] The invention relates to a phosphorus-doped metal nickel catalyst prepared based on tetrabutylphosphine chloride / glycerol low eutectic solvent and a preparation method and application thereof, belonging to the technical field of functional materials. Background Art

[0002] Nickel-based catalysts have broad application prospects in the field of hydrogen evolution by water electrolysis due to their good conductivity, stability and relatively low cost. However, the catalytic performance of traditional nickel-based catalysts still needs to be further improved. In order to optimize the performance of nickel-based catalysts, researchers have tried a variety of methods, such as morphology regulation, surface modification and heteroatom doping. Among them, phosphorus doping is considered to be an effective strategy to improve the performance of nickel-based catalysts.

[0003] Currently, the preparation methods of phosphorus-doped metallic nickel include hydrothermal synthesis or vapor phase phosphating, but these methods have the following disadvantages: (1) Difficulty in control: The phosphorus doping process requires precise control of the doping concentration and position to avoid adverse effects, which places higher requirements on material preparation and process technology, and increases the preparation cost and difficulty; (2) The presence of harmful substances: Phosphorus may cause certain harm to the environment and human health at high concentrations; (3) Complex process requirements: Some preparation methods, such as vapor phase phosphating, require complex process conditions such as high temperature and high pressure, which increases the complexity and cost of the preparation process.

[0004] Therefore, it is of great significance to explore a new synthesis method of phosphorus-doped nickel-based catalyst in order to obtain a catalyst with excellent water electrolysis hydrogen evolution performance. To this end, the present invention is proposed. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a phosphorus-doped metal nickel catalyst prepared based on tetrabutylphosphine chloride / glycerol deep eutectic solvent, and its preparation method and application. The present invention first designs a new deep eutectic solvent (DES) composed of tetrabutylphosphine chloride and glycerol, then dissolves nickel nitrate in the deep eutectic solvent system, and heats it to obtain a thin-flaked P-doped metal nickel catalyst with good hydrogen evolution performance.

[0006] The technical solution of the present invention is as follows:

[0007] A method for preparing a phosphorus-doped metal nickel catalyst based on tetrabutylphosphine chloride / propylene glycol deep eutectic solvent comprises the following steps:

[0008] (1) mixing tetrabutylphosphine chloride and propylene glycol at 55-120° C. to obtain a deep eutectic solvent;

[0009] (2) adding nickel nitrate to a low eutectic solvent, mixing uniformly by ultrasonication, and then heating; cooling, washing, and drying to obtain a phosphorus-doped metal nickel catalyst prepared based on a tetrabutylphosphine chloride / propylene glycol low eutectic solvent.

[0010] Preferably according to the present invention, the molar ratio of tetrabutylphosphine chloride to glycerol in step (1) is 0.2-5:1, more preferably 0.5-2:1, and more preferably 0.5:1.

[0011] According to a preferred embodiment of the present invention, the preparation method of the low eutectic solvent in step (1) is as follows: tetrabutylphosphine chloride and propylene glycol are mixed at 55-120° C. under stirring conditions, and reacted until a colorless transparent liquid is formed to obtain a low eutectic solvent. It is further preferred that tetrabutylphosphine chloride and propylene glycol are mixed at 80° C.

[0012] Preferably according to the present invention, the nickel nitrate in step (2) is added to a low eutectic solvent at room temperature.

[0013] Preferably according to the present invention, the ratio of the molar number of nickel nitrate to the mass of the low eutectic solvent in step (2) is 0.02-1mmol:1g, and more preferably 0.1mmol:1g.

[0014] Preferably, according to the present invention, the temperature of the heating treatment in step (2) is 300-450°C, more preferably 350°C; the time of the heating treatment is 1-5h, more preferably 3h; the heating rate is 5-15°C / min, more preferably 10°C / min; and the heating treatment is carried out under a nitrogen atmosphere.

[0015] Preferably, in step (2), the cooling is performed by natural cooling to room temperature, the washing is performed by centrifugal washing with ethanol and water for 3-5 times respectively, and the drying is performed by vacuum drying at room temperature for 20-30 hours.

[0016] In the present invention, room temperature has a well-known meaning in the art, which refers to 25±5°C.

[0017] The present invention also provides a phosphorus-doped metal nickel catalyst prepared based on tetrabutylphosphine chloride / propylene glycol low eutectic solvent, which is prepared by the above-mentioned preparation method.

[0018] According to the present invention, the phosphorus-doped metal nickel catalyst prepared based on the tetrabutylphosphine chloride / propylene glycol low eutectic solvent is used as a catalyst for hydrogen evolution by electrolysis of water.

[0019] The technical features and beneficial effects of the present invention are as follows:

[0020] 1. The low eutectic solvent DES prepared by tetrabutylphosphine chloride / propylene glycol in the present invention can not only serve as a good template to guide the nickel catalyst to form a special morphology, and finally obtain an angular flaky structure, thereby increasing the catalytic active sites; more importantly, tetrabutylphosphine chloride can also provide phosphorus elements for the reaction system, and successfully dope them into the nickel catalyst, thereby preparing a phosphorus-doped nickel catalyst with excellent catalytic performance.

[0021] 2. The catalyst prepared by the present invention has a good electrolysis of water. One reason is that nickel metal itself can be used as a good catalyst for hydrogen evolution reaction due to its excellent conductivity, which ensures rapid electron transfer during the electrode reaction. On this basis, phosphorus (P) doping can modify nickel, thereby further improving its catalytic efficiency. The introduction of P atoms into the nickel lattice will cause lattice distortion. At the same time, P doping may enhance the adsorption capacity and stability of these reactants on the catalyst surface. The unique morphology is another important factor for the high catalytic activity of the catalyst. Compared with bulk materials, the flaky structure provides additional reaction surfaces. More surfaces mean more active sites for adsorbing water molecules, thereby increasing the rate of hydrogen evolution reaction. In addition, it enables hydrogen ions to diffuse to the active sites within a shorter distance, and quickly diffuse from both sides and edges of the flaky structure, reducing transmission resistance and accelerating hydrogen evolution reaction. The excellent performance of the catalyst of the present invention is the result of the synergistic effect of structural composition and morphology.

[0022] 3. The preparation method of the catalyst of the present invention is simple, low-cost and suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is the XRD pattern of the phosphorus-doped metal nickel catalyst prepared based on the tetrabutylphosphine chloride / glycerol low eutectic solvent prepared in Example 1, wherein the abscissa is the diffraction angle and the ordinate is the intensity.

[0024] Figure 2 This is the XPS nickel spectrum of the phosphorus-doped metal nickel catalyst prepared based on tetrabutylphosphine chloride / glycerol low eutectic solvent prepared in Example 1, wherein the abscissa is the binding energy and the ordinate is the intensity.

[0025] Figure 3 This is the XPS phosphorus spectrum of the phosphorus-doped metal nickel catalyst prepared based on tetrabutylphosphine chloride / glycerol low eutectic solvent prepared in Example 1, wherein the abscissa is the binding energy and the ordinate is the intensity.

[0026] Figure 4 This is a TEM image of the phosphorus-doped metal nickel catalyst prepared based on tetrabutylphosphine chloride / glycerol deep eutectic solvent prepared in Example 1.

[0027] Figure 5LSV curves of the phosphorus-doped metal nickel catalyst prepared based on tetrabutylphosphine chloride / glycerol deep eutectic solvent prepared in Example 1 under acidic and alkaline conditions.

[0028] Figure 6 Shown are the LSV curves of the substrate nickel foam under acidic and alkaline conditions. DETAILED DESCRIPTION

[0029] The present invention will be further described below with reference to specific embodiments, but is not limited thereto.

[0030] Meanwhile, the experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0031] Example 1

[0032] A method for preparing a phosphorus-doped metal nickel catalyst based on tetrabutylphosphine chloride / propylene glycol deep eutectic solvent comprises the following steps:

[0033] (1) Preparation of deep eutectic solvent (DES)

[0034] First, tetrabutylphosphine chloride and propylene glycol are weighed in a molar ratio of 1:2 and mixed; then, the mixed system is placed in an oil bath at 80° C. and continuously stirred using a magnetic stirring device until a colorless, transparent, uniform liquid is formed, which is the tetrabutylphosphine chloride / propylene glycol low eutectic solvent.

[0035] (2) Preparation of phosphorus-doped nickel catalyst

[0036] Take 5 g of the low eutectic solvent obtained in step (1), add 0.5 mmol of nickel nitrate hexahydrate to the low eutectic solvent at room temperature, and mix evenly by ultrasonication; transfer the above solution to a crucible, place it in a tubular furnace, and heat it to 350°C at a heating rate of 10°C / min in a nitrogen atmosphere, and keep it at 350°C for 3h; after the reaction is completed, naturally cool to room temperature, and the obtained product is centrifuged and washed 5 times with ethanol and water respectively to remove organic impurities and by-products, the centrifugal speed is 10000rpm, and a black precipitate is obtained. The obtained precipitate is then vacuum dried at room temperature for 24h to obtain a phosphorus-doped metal nickel catalyst prepared based on tetrabutylphosphine chloride / propylene glycol low eutectic solvent.

[0037] The XRD pattern of the phosphorus-doped nickel catalyst prepared based on tetrabutylphosphine chloride / propylene glycol deep eutectic solvent obtained in this example is as follows: Figure 1 As shown by Figure 1 It can be seen that nickel (JCPDS 65-2865) was successfully obtained; Figure 2-3The nickel and phosphorus spectra of XPS are respectively, which proves that the obtained material contains nickel and phosphorus. The peaks of nickel and phosphorus are shifted, which proves that phosphorus is successfully doped into nickel. Figure 4 TEM image of the phosphorus-doped metal nickel catalyst prepared based on tetrabutylphosphine chloride / propylene glycol low eutectic solvent, showing that its morphology is a flaky morphology with edges and corners.

[0038] Example 2

[0039] A method for preparing a phosphorus-doped metal nickel catalyst based on a tetrabutylphosphine chloride / propylene glycol low eutectic solvent is as described in Example 1, except that in step (1), tetrabutylphosphine chloride and propylene glycol are weighed in a molar ratio of 4:1.

[0040] Example 3

[0041] A method for preparing a phosphorus-doped metal nickel catalyst based on a tetrabutylphosphine chloride / propylene glycol low eutectic solvent is as described in Example 1, except that in step (1), tetrabutylphosphine chloride and propylene glycol are weighed in a molar ratio of 1:4.

[0042] Example 4

[0043] A method for preparing a phosphorus-doped metal nickel catalyst based on tetrabutylphosphine chloride / propylene glycol low eutectic solvent is as described in Example 1, except that: in step (2), the low eutectic solvent is 1 g.

[0044] Example 5

[0045] A method for preparing a phosphorus-doped metal nickel catalyst based on a tetrabutylphosphine chloride / propylene glycol low eutectic solvent is as described in Example 1, except that: in step (2), the low eutectic solvent is 10 g.

[0046] Example 6

[0047] A method for preparing a phosphorus-doped metal nickel catalyst based on tetrabutylphosphine chloride / propylene glycol low eutectic solvent is as described in Example 1, except that: in step (2), the nickel nitrate hexahydrate is 0.2 mmol.

[0048] Example 7

[0049] A method for preparing a phosphorus-doped metal nickel catalyst based on tetrabutylphosphine chloride / propylene glycol low eutectic solvent is as described in Example 1, except that: in step (2), the nickel nitrate hexahydrate is 2 mmol.

[0050] Example 8

[0051] A method for preparing a phosphorus-doped metal nickel catalyst based on tetrabutylphosphine chloride / propylene glycol low eutectic solvent is as described in Example 1, except that: the heat treatment temperature in step (2) is 300°C.

[0052] Example 9

[0053] A method for preparing a phosphorus-doped metal nickel catalyst based on tetrabutylphosphine chloride / propylene glycol low eutectic solvent is as described in Example 1, except that: the heat treatment temperature in step (2) is 450°C.

[0054] Example 10

[0055] A method for preparing a phosphorus-doped metal nickel catalyst based on tetrabutylphosphine chloride / propylene glycol low eutectic solvent is as described in Example 1, except that the holding time of the heat treatment in step (2) is 1 hour.

[0056] Embodiment 11

[0057] A method for preparing a phosphorus-doped metal nickel catalyst based on tetrabutylphosphine chloride / propylene glycol low eutectic solvent is as described in Example 1, except that the holding time of the heat treatment in step (2) is 5 hours.

[0058] Example 12

[0059] A method for preparing a phosphorus-doped metal nickel catalyst based on tetrabutylphosphine chloride / propylene glycol low eutectic solvent is as described in Example 1, except that in step (1), the mixed system is placed in an oil bath environment at 55°C.

[0060] Embodiment 13

[0061] A method for preparing a phosphorus-doped metal nickel catalyst based on tetrabutylphosphine chloride / propylene glycol low eutectic solvent is as described in Example 1, except that in step (1), the mixed system is placed in an oil bath environment at 120°C.

[0062] Test Example 1

[0063] The phosphorus-doped metal nickel catalyst prepared based on tetrabutylphosphine chloride / propylene glycol deep eutectic solvent prepared in Example 1 is used for electrolysis of water for hydrogen evolution, and the specific application steps are as follows:

[0064] The electrochemical data were obtained by an electrochemical workstation (Shanghai Chenhua CHI 760E). A standard three-electrode system was used, in which a saturated calomel electrode was used as a reference electrode, graphite was used as a counter electrode, and nickel foam modified with the phosphorus-doped metal nickel catalyst prepared in Example 1 (modification amount 0.35 mg cm -2) as the working electrode. After vacuum drying at room temperature, 5uL 0.2% Nafion was modified to prevent the metal nickel from falling off. The data obtained were obtained in 0.5mol / L H2SO4 solution and 1.0mol / L KOH solution (electrolyte) at room temperature, and all electrode potentials were converted to standard hydrogen electrode potential (RHE). At the same time, pure foam nickel without modification was used as a comparison.

[0065] The phosphorus-doped nickel catalyst prepared by the present invention has a 10 mA cm -2 The overpotential corresponding to the current density (η 10 ) is 90.2mV( Figure 5 ), 10 mA cm in 1.0 mol / L KOH solution -2 The overpotential corresponding to the current density (η 10 ) is 107mV( Figure 5 ). Pure nickel foam without modified catalyst in 0.5 mol / L H2SO4 at 10 mA cm -2 The overpotential corresponding to the current density (η 10 ) is 226.4mV( Figure 6 ), 10 mA cm in 1.0 mol / L KOH solution -2 The overpotential corresponding to the current density (η 10 ) is 284.5mV( Figure 6 ).

Claims

1. A method for preparing a phosphorus-doped metal nickel catalyst based on tetrabutylphosphine chloride / propylene glycol deep eutectic solvent, comprising the following steps: (1) mixing tetrabutylphosphine chloride and propylene glycol at 55-120° C. to obtain a deep eutectic solvent; (2) adding nickel nitrate to a low eutectic solvent, mixing uniformly by ultrasonication, and then heating; cooling, washing, and drying to obtain a phosphorus-doped metal nickel catalyst prepared based on a tetrabutylphosphine chloride / propylene glycol low eutectic solvent.

2. The method for preparing a phosphorus-doped metal nickel catalyst prepared based on tetrabutylphosphine chloride / glycerol deep eutectic solvent according to claim 1, characterized in that: The molar ratio of tetrabutylphosphine chloride to glycerol in step (1) is 0.2-5:1, preferably 0.5-2:1, and more preferably 0.5:

1.

3. The method for preparing a phosphorus-doped metal nickel catalyst prepared based on tetrabutylphosphine chloride / glycerol deep eutectic solvent according to claim 1, characterized in that: The preparation method of the low eutectic solvent in step (1) is as follows: tetrabutylphosphine chloride and propylene glycol are mixed at 55-120° C. under stirring conditions, and reacted until a colorless transparent liquid is formed to obtain a low eutectic solvent. Preferably, tetrabutylphosphine chloride and propylene glycol are mixed at 80° C.

4. The method for preparing a phosphorus-doped metal nickel catalyst prepared based on tetrabutylphosphine chloride / glycerol deep eutectic solvent according to claim 1, characterized in that: The nickel nitrate in step (2) is added to a low eutectic solvent at room temperature.

5. The method for preparing a phosphorus-doped metal nickel catalyst prepared based on tetrabutylphosphine chloride / glycerol deep eutectic solvent according to claim 1, characterized in that: The mass ratio of the molar number of nickel nitrate to the low eutectic solvent in step (2) is 0.02-1mmol:1g, preferably 0.1mmol:1g.

6. The method for preparing a phosphorus-doped metal nickel catalyst based on tetrabutylphosphine chloride / glycerol deep eutectic solvent according to claim 1, characterized in that: The temperature of the heating treatment in step (2) is 300-450°C, preferably 350°C; the time of the heating treatment is 1-5h, preferably 3h; the heating rate is 5-15°C / min, preferably 10°C / min; the heating treatment is carried out under a nitrogen atmosphere.

7. The method for preparing a phosphorus-doped metal nickel catalyst based on tetrabutylphosphine chloride / glycerol deep eutectic solvent according to claim 1, characterized in that: The cooling in step (2) is natural cooling to room temperature, the washing is centrifugal washing using ethanol and water in sequence for 3-5 times each; and the drying is vacuum drying at room temperature for 20-30 hours.

8. A phosphorus-doped metal nickel catalyst prepared based on tetrabutylphosphine chloride / propylene glycol deep eutectic solvent, characterized in that: The preparation method according to claim 1 is used for preparation.

9. Use of the phosphorus-doped metal nickel catalyst prepared based on tetrabutylphosphine chloride / propylene glycol deep eutectic solvent according to claim 8 as a catalyst for hydrogen evolution by electrolysis of water.

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