Defect-rich carbon-loaded transition metal / metal oxide as well as preparation method and application thereof

Abstract

The invention discloses a defect-rich carbon-loaded transition metal / metal oxide and a preparation method and application thereof.The preparation method comprises the steps that firstly, a fullerene matrix is assembled to the surface of a SiO2 mesoporous template, then carbonization is conducted, an organic solvent and the template are removed through acid etching, and therefore a defective fullerene fragment F is generated to serve as a metal anchoring site M (at) F; and finally, slowly oxidizing in air to obtain a metal / metal oxide M / Mox composite array. According to the defective carbon-loaded transition metal / metal oxide prepared by the invention, an electron buffer system at an M / MOx interface can balance charge transfer between HER and OER by providing electrons for electron-deficient HER and adapting to an electron donor OER, so that the electrocatalytic activity is enhanced.

Description

Technical Field

[0001] The present invention relates to the field of electrocatalysis technology, and in particular to a defect-rich carbon-loaded transition metal / metal oxide and a preparation method and application thereof. Background Art

[0002] With the continuous consumption of traditional fossil energy, it is urgent to find new sustainable energy to deal with the energy crisis and environmental problems caused by traditional fossil fuels. Electrocatalytic water splitting, powered by green sustainable energy systems such as wind energy and tidal energy, can produce two clean energies, hydrogen and oxygen, and is therefore regarded as a highly promising way to produce clean energy.

[0003] In the process of electrocatalytic water decomposition, both the oxygen evolution reaction (OER) at the anode and the hydrogen evolution reaction (HER) at the cathode require the help of catalysts to reduce the overpotential. The use of bifunctional electrocatalysts that have both HER and OER catalytic functions can simplify the electrolysis system and significantly reduce costs. However, current bifunctional catalysts face many challenges, such as high electrolysis voltage, limited current density, and poor stability. Therefore, it is particularly important to develop efficient, durable and inexpensive bifunctional water electrolysis catalysts.

[0004] More importantly, in most cases, catalysts undergo surface reconstruction during electrochemical HER and / or OER, which often results in structural damage to the catalyst, leading to reduced activity. Summary of the invention

[0005] The purpose of the present invention is to provide a defect-rich carbon-supported transition metal / metal oxide and a preparation method and application thereof, wherein the prepared synthetic M / MO x @FThe structure of electrocatalytic materials is controllable and has both HER and OER catalytic functions.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A method for preparing defect-rich carbon-loaded transition metal / metal oxide comprises the following steps:

[0008] Step 1: Dissolve 2-6g of the amphiphilic block copolymer P123 in 58-232mL of 1-6M hydrochloric acid solution, slowly add 3.5-10.4mL of TEOS and heat to allow TEOS to undergo hydrolysis and condensation reactions, then transfer the mixed solution to an autoclave for reaction, collect the precipitate after the reaction is completed, wash it with deionized water, dry it, and calcine it at 540°C to prepare ordered mesoporous SiO2 powder;

[0009] Step 2: dissolving fullerene in an organic solvent to obtain a saturated fullerene solution, immersing the SiO2 powder prepared in step 1 in the saturated fullerene solution so that the fullerene is assembled into the pores of SiO2 to obtain a solid product F / SiO2, wherein the mass ratio of fullerene to SiO2 is (0.3-0.6):1; annealing the F / SiO at a temperature of 500-950°C in a protective gas environment, and then etching away the SiO2 of the F / SiO2 using an HF solution to obtain a purified black sample F;

[0010] Step 3: F was dispersed in a mixture of EtOH and DI water in a volume ratio of 1:2, and then the transition metal salt was added in a mass ratio of F to transition metal salt (2-4): 1 and stirred thoroughly at 25°C, and then 20-40 mL of a freshly prepared NaBH4 solution with a concentration of 0.5-3 mg / mL was dropped and stirred evenly, filtered, washed, and vacuum dried at 60°C to obtain a black powder M@F;

[0011] Step 4: Place M@F in a tube furnace and heat at 200-400°C for 1-3 hours to obtain a solid product M / MO x @F.

[0012] Furthermore, the heating temperature in step 1 is 35-45° C., and the heating time is 12-48 hours.

[0013] Furthermore, the mixed solution in step 1 is kept at a volume filling ratio of 30% to 70% in the autoclave, the temperature of the autoclave is 100-180° C., and the reaction time is 36-60 hours.

[0014] Furthermore, the organic solvent in step 2 is one of monochloronaphthalene, toluene, xylene, mesitylene, and isopropylbenzene.

[0015] Furthermore, the protective gas in step 2 is one of argon, nitrogen and ammonia.

[0016] Furthermore, the salt in the transition metal salt in step three is one or a combination of nitrates, sulfates, chlorides and organic complexes of metals, and the metal in the transition metal salt is one or a combination of ruthenium, platinum, palladium, iron, cobalt and nickel.

[0017] The defect-rich carbon-supported transition metal / metal oxide prepared by the above method, the synthesized M / MO x The electrocatalytic material structure of @F is that metal particles are anchored on defect-rich carbon F, and the applied potential is between M and MO during HER and OER. x Reversibly shuttles between active sites, M and MO x The synergistic effect between them ensures the good catalytic activity of the catalyst.

[0018] The present invention also provides an application of defect-rich carbon-loaded transition metal / metal oxide in a bifunctional water electrolysis catalyst.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The defect-rich carbon loaded transition metal / metal oxide prepared by the present invention uses a nano-hard template method and utilizes the high solubility of fullerene in organic solvents to encapsulate a large number of fullerene molecules into the mesopores of the SiO2 template, thereby preparing a defect-rich carbon substrate. This method allows the final defect-rich carbon F to have a rod-like morphology, a high specific surface area, a high mesopore density and a large mesopore volume. The resulting mixture is then directly carbonized at high temperature, so that the defect-rich carbon F has excellent thermal stability. Finally, the transition metal M is loaded on F by a room temperature reduction method, and oxidized in air to make M / MO x @F The M nanoclusters are partially oxidized to MO with rich oxygen vacancies (VO) x .M / MO x The dynamic transition between the two generates more fresh active sites with flexible balance of electron density, thus enhancing the electrocatalytic activity.

[0021] The preparation method provided by the present invention has the characteristics of simple process, mild reaction conditions, easy implementation, easy controllable process, safe and feasible. Moreover, the size and morphology of the mesoporous SiO2 template can be controlled by adjusting the reaction temperature and reaction time. M / MO is synthesized by anchoring metal particles on defect-rich carbon F x @F electrocatalytic material with better bifunctional electrocatalytic activity for hydrogen and oxygen evolution, with a potential between M and MO during HER and OER x Reversibly shuttle between active sites. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The XRD pattern of Ru / RuO2@F prepared in Example 1 of the present invention;

[0023] Figure 2 This is the SEM spectrum of Ru / RuO2@F prepared in Example 1 of the present invention;

[0024] Figure 3 AC HAADF-STEM spectrum of Ru / RuO2@F prepared in Example 1 of the present invention;

[0025] Figure 4 HER LSV curve of Ru / RuO2@F prepared in Example 1 of the present invention in 1M KOH;

[0026] Figure 5This is the OER LSV curve of Ru / RuO2@F prepared in Example 1 of the present invention in 1M KOH. DETAILED DESCRIPTION

[0027] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] Example 1: A method for preparing defect-rich carbon-loaded transition metal / metal oxide, comprising the following steps:

[0029] Step 1: 3 g of P123 was dissolved in 87 mL of 2M HCl, 6.9 mL of TEOS was slowly added and heated at 40 ° C for 24 h to allow TEOS to undergo hydrolysis and condensation reactions, and then the mixed solution was transferred to an autoclave with a volume filling ratio of 50%, and heated at 130 ° C for 48 h to react. After the reaction was completed, the precipitate was collected and washed with deionized water, dried at 100 ° C for 6 h, and then calcined at 540 ° C to prepare ordered mesoporous SiO2 powder;

[0030] Step 2: dissolving fullerene in monochloronaphthalene to obtain a saturated fullerene solution, immersing the SiO2 powder prepared in step 1 in the saturated fullerene solution so that the fullerene is assembled into the pores of SiO2 to obtain a solid product F / SiO2, wherein the mass ratio of fullerene to SiO2 is 0.4:1; annealing the F / SiO at 900°C in an argon environment, and then etching away the SiO2 of the F / SiO2 using an HF solution to obtain a purified black sample F;

[0031] Step 3: F was dispersed in a mixture of EtOH and DI water in a volume ratio of 1:2, and then RuCl3 was added in a mass ratio of F to RuCl3 of 3.3:1 and stirred thoroughly at 25°C, and then 20 mL of a freshly prepared NaBH4 solution with a concentration of 1 mg / mL was dropped and stirred evenly, filtered, washed, and vacuum dried at 60°C to obtain black powder Ru@F;

[0032] Step 4: Place Ru@F in a tube furnace and heat at 300°C and keep warm for 2 hours to obtain a solid product Ru / RuO2@F.

[0033] The Ru / RuO2@F prepared in Example 1 was subjected to an X-ray diffraction experiment and the following results were obtained: Figure 1 The XRD pattern shown in the figure, by comparison with the standard card, shows that the sample contains the characteristic peaks of Ru (PDF#06-0663) and RuO2 (PDF#43-1027) of the typical hexagonal close-packed (hcp) structure, further proving that Ru and RuO2 co-exist in the Ru / RuO2@F catalyst.

[0034] The Ru / RuO2@F prepared in Example 1 was analyzed by scanning electron microscope. Figure 2 The SEM image shown in the figure shows that the prepared Ru / RuO2@F catalyst maintains a rod-shaped morphology.

[0035] The Ru / RuO2@F prepared in Example 1 was examined by a high-angle annular dark-field scanning transmission electron microscope, and the following results were obtained: Figure 3 The HAADF-STEM image shown in the figure shows that the interplanar spacing is can be expressed as the (002) plane of the hexagonal Ru phase, and the interplanar spacing is It belongs to the (200) crystal plane of the tetragonal RuO2 phase, which further explains the formation of the Ru / RuO2 interface in the prepared Ru / RuO2@F catalyst.

[0036] According to the standard electrochemical test method, the Ru / RuO2@F prepared in Example 1 was subjected to linear voltammetric sweep experiments of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), and the following results were obtained: Figure 4 , 5 The LSV curve is shown in Figure 1. It can be seen from the figure that when the current density passing through the electrode is 10mAcm -2 When the overpotential of HER reaction to produce hydrogen in alkaline aqueous solution is only 10 mV, the overpotential of OER reaction to produce oxygen in alkaline aqueous solution is 230 mV, which further illustrates that the synergistic effect of Ru and RuO2 interface ensures the excellent electrocatalytic hydrogen and oxygen evolution activity of Ru / RuO2@F catalyst.

[0037] Example 2: A method for preparing defect-rich carbon-loaded transition metal / metal oxide, comprising the following steps:

[0038] Step 1: 3 g of P123 was dissolved in 87 mL of 4 M HCl, 6.9 mL of TEOS was slowly added and heated at 35 ° C for 40 h to allow TEOS to undergo hydrolysis and condensation reactions, and then the mixed solution was transferred to an autoclave with a volume filling ratio of 30%, and heated at 100 ° C for 55 h to react. After the reaction was completed, the precipitate was collected and washed with deionized water, dried at 100 ° C for 6 h, and then calcined at 540 ° C to prepare ordered mesoporous SiO2 powder;

[0039] Step 2: dissolving fullerene in monochloronaphthalene to obtain a saturated fullerene solution, immersing the SiO2 powder prepared in step 1 in the saturated fullerene solution so that the fullerene is assembled into the pores of SiO2 to obtain a solid product F / SiO2, wherein the mass ratio of fullerene to SiO2 is 0.4:1; annealing the F / SiO at 900°C in an argon environment, and then etching away the SiO2 of the F / SiO2 using an HF solution to obtain a purified black sample F;

[0040] Step 3: F was dispersed in a mixture of EtOH and DI water in a volume ratio of 1:2, and then a transition metal salt (a mixture of H2PtCl6 and NiCl2) was added in a mass ratio of F to transition metal salt of 4:1 and stirred thoroughly at 25°C, and then 20 mL of a freshly prepared NaBH4 solution with a concentration of 0.5 mg / mL was dropped and stirred evenly, filtered, washed, and dried in vacuum at 60°C to obtain black powder NiPt@F;

[0041] Step 4: Place Ru@F in a tube furnace and heat at 200°C and keep warm for 3 hours to obtain a solid product Pt / NiO@F.

[0042] Example 3: A method for preparing defect-rich carbon-loaded transition metal / metal oxide, comprising the following steps:

[0043] Step 1: 6 g of P123 was dissolved in 58 mL of 6 M HCl, 8.5 mL of TEOS was slowly added and heated at 45 ° C for 12 h to allow TEOS to undergo hydrolysis and condensation reactions, and then the mixed solution was transferred to an autoclave with a volume filling ratio of 50%, and heated at 150 ° C for 40 h to react. After the reaction was completed, the precipitate was collected and washed with deionized water, dried at 100 ° C for 6 h, and then calcined at 540 ° C to prepare ordered mesoporous SiO2 powder;

[0044] Step 2: dissolving fullerene in toluene to obtain a saturated fullerene solution, and immersing the SiO2 powder prepared in step 1 in the saturated fullerene solution so that the fullerene is assembled into the pores of SiO2 to obtain a solid product F / SiO2, wherein the mass ratio of fullerene to SiO2 is 0.3:1; annealing the F / SiO at 950°C in a nitrogen environment, and then etching away the SiO2 of the F / SiO2 using an HF solution to obtain a purified black sample F;

[0045] Step 3: F was dispersed in a mixture of EtOH and DI water in a volume ratio of 1:2, and then a transition metal salt (a mixture of Co(NO3)2 and H2PtCl6) was added in a mass ratio of 3:1 between F and the transition metal salt and stirred thoroughly at 25°C, and then 40 mL of a freshly prepared NaBH4 solution with a concentration of 0.5 mg / mL was dropped and stirred evenly, filtered, washed, and dried in vacuum at 60°C to obtain a black powder CoPt@F;

[0046] Step 4: Place Ru@F in a tube furnace and heat at 350°C and keep warm for 2 hours to obtain the solid product Ru / RuO2@F.

[0047] Example 4: A method for preparing defect-rich carbon-loaded transition metal / metal oxide, comprising the following steps:

[0048] Step 1: 2 g of P123 was dissolved in 116 mL of 2M HCl, 5.4 mL of TEOS was slowly added and heated at 36 ° C for 48 h to allow TEOS to undergo hydrolysis and condensation reactions, and then the mixed solution was transferred to an autoclave with a volume filling ratio of 70% and heated at 120 ° C for 60 h to react. After the reaction was completed, the precipitate was collected and washed with deionized water, dried at 100 ° C for 6 h, and then calcined at 540 ° C to prepare ordered mesoporous SiO2 powder;

[0049] Step 2: dissolving fullerene in xylene to obtain a saturated fullerene solution, immersing the SiO2 powder prepared in step 1 in the saturated fullerene solution so that the fullerene is assembled into the pores of SiO2 to obtain a solid product F / SiO2, wherein the mass ratio of fullerene to SiO2 is 0.5:1; annealing the F / SiO at 500°C in an ammonia environment, and then etching away the SiO2 of the F / SiO2 using an HF solution to obtain a purified black sample F;

[0050] Step 3: F was dispersed in a mixture of EtOH and DI water in a volume ratio of 1:2, and then a transition metal salt (a mixture of PdCl2 and Fe2(SO4)3) was added in a mass ratio of F to transition metal salt of 3.5:1 and stirred thoroughly at 25°C, and then 40 mL of a freshly prepared NaBH4 solution with a concentration of 3 mg / mL was dropped and stirred evenly, and then filtered, washed, and dried in vacuum at 60°C to obtain a black powder PdFe@F;

[0051] Step 4: Place Ru@F in a tube furnace and heat at 280°C for 1.5 h to obtain a solid product Ru / RuO2@F.

[0052] Example 5: A method for preparing defect-rich carbon-loaded transition metal / metal oxide, comprising the following steps:

[0053] Step 1: 4 g P123 was dissolved in 200 mL 3M HCl, 3.5 mL TEOS was slowly added and heated at 40 ° C for 36 h to allow TEOS to undergo hydrolysis and condensation reactions, and then the mixed solution was transferred to an autoclave with a volume filling ratio of 60%, and heated at 130 ° C for 48 h to react. After the reaction was completed, the precipitate was collected and washed with deionized water, dried at 100 ° C for 6 h, and then calcined at 540 ° C to prepare ordered mesoporous SiO2 powder;

[0054] Step 2: dissolving fullerene in mesitylene to obtain a saturated fullerene solution, immersing the SiO2 powder prepared in step 1 in the saturated fullerene solution so that the fullerene is assembled into the pores of SiO2 to obtain a solid product F / SiO2, wherein the mass ratio of fullerene to SiO2 is 0.6:1; annealing the F / SiO at 800°C in a nitrogen environment, and then etching away the SiO2 of the F / SiO2 using an HF solution to obtain a purified black sample F;

[0055] Step 3: F was dispersed in a mixture of EtOH and DI water in a volume ratio of 1:2, and then RuCl3 was added in a mass ratio of F to RuCl3 of 2:1 and stirred thoroughly at 25°C, and then 20 mL of a freshly prepared NaBH4 solution with a concentration of 3 mg / mL was dropped and stirred evenly, filtered, washed, and vacuum dried at 60°C to obtain black powder Ru@F;

[0056] Step 4: Place Ru@F in a tube furnace and heat at 400°C and keep warm for 1 hour to obtain a solid product Ru / RuO2@F.

[0057] Example 6: A method for preparing defect-rich carbon-loaded transition metal / metal oxide, comprising the following steps:

[0058] Step 1: 5 g of P123 was dissolved in 160 mL of 5 M HCl, 10.4 mL of TEOS was slowly added and heated at 42 ° C for 24 h to allow TEOS to undergo hydrolysis and condensation reactions, and then the mixed solution was transferred to an autoclave with a volume filling ratio of 40%, and heated at 160 ° C for 36 h to react. After the reaction was completed, the precipitate was collected and washed with deionized water, dried at 100 ° C for 6 h, and then calcined at 540 ° C to prepare ordered mesoporous SiO2 powder;

[0059] Step 2: dissolving fullerene in mesitylene to obtain a saturated fullerene solution, immersing the SiO2 powder prepared in step 1 in the saturated fullerene solution so that the fullerene is assembled into the pores of SiO2 to obtain a solid product F / SiO2, wherein the mass ratio of fullerene to SiO2 is 0.45:1; annealing the F / SiO at 700°C in an argon environment, and then etching away the SiO2 of the F / SiO2 using an HF solution to obtain a purified black sample F;

[0060] Step 3: F was dispersed in a mixture of EtOH and DI water in a volume ratio of 1:2, and then RuCl3 was added in a mass ratio of 3:1 between F and RuCl3 and stirred at 25°C, and then 20 mL of a freshly prepared NaBH4 solution with a concentration of 1.5 mg / mL was dropped into the mixture and stirred evenly. After filtering, washing, and vacuum drying at 60°C, black powder Ru@F was obtained;

[0061] Step 4: Place Ru@F in a tube furnace and heat at 260°C for 2.5 h to obtain a solid product Ru / RuO2@F.

[0062] Example 7: A method for preparing defect-rich carbon-supported transition metal / metal oxide, comprising the following steps:

[0063] Step 1: 2 g of P123 was dissolved in 232 mL of 2M HCl, 9 mL of TEOS was slowly added and heated at 38 ° C for 30 h to allow TEOS to undergo hydrolysis and condensation reactions, and then the mixed solution was transferred to an autoclave with a volume filling ratio of 50%, and heated at 180 ° C for 42 h to react. After the reaction was completed, the precipitate was collected and washed with deionized water, dried at 100 ° C for 6 h, and then calcined at 540 ° C to prepare ordered mesoporous SiO2 powder;

[0064] Step 2: dissolving fullerene in cumene to obtain a saturated fullerene solution, immersing the SiO2 powder prepared in step 1 in the saturated fullerene solution so that the fullerene is assembled into the pores of SiO2 to obtain a solid product F / SiO2, wherein the mass ratio of fullerene to SiO2 is 0.35:1; annealing the F / SiO at 600°C in an ammonia environment, and then etching away the SiO2 of the F / SiO2 using an HF solution to obtain a purified black sample F;

[0065] Step 3: F was dispersed in a mixed solution prepared by EtOH and DI water in a volume ratio of 1:2, and then the organic complex of the metal was added in a mass ratio of 2.5:1 (the organic complex of the metal was a mixture of ruthenium (III) organic complex ruthenium acetylacetonate (Ru(acac)3) and Pd(II) organic complex acetylacetonate palladium (Pd(acac)2)) and stirred thoroughly at 25°C, and then 30mL of a freshly prepared NaBH4 solution with a concentration of 2.5mg / mL was dropped and stirred evenly, and then filtered, washed, and vacuum dried at 60°C to obtain black powder RuPd@F;

[0066] Step 4: Place Ru@F in a tube furnace and heat at 300°C and keep warm for 2 hours to obtain a solid product Pd / RuO2@F.

Claims

1. A method for preparing defect-rich carbon-supported transition metal / metal oxide, characterized in that: The steps include: Step 1: Dissolve 2-6g of the amphiphilic block copolymer P123 in 58-232mL of 1-6M hydrochloric acid solution, slowly add 3.5-10.4mL of TEOS and heat to allow TEOS to undergo hydrolysis and condensation reactions, then transfer the mixed solution to an autoclave for reaction, collect the precipitate after the reaction is completed, wash it with deionized water, dry it, and calcine it at 540°C to prepare ordered mesoporous SiO2 powder; Step 2: dissolving fullerene in an organic solvent to obtain a saturated fullerene solution, immersing the SiO2 powder prepared in step 1 in the saturated fullerene solution so that the fullerene is assembled into the pores of SiO2 to obtain a solid product F / SiO2, wherein the mass ratio of fullerene to SiO2 is (0.3-0.6):1; annealing the F / SiO2 at a temperature of 500-950°C in a protective gas environment, and then etching away the SiO2 of the F / SiO2 using an HF solution to obtain a purified black sample F; Step 3: F was dispersed in a mixture of EtOH and DI water in a volume ratio of 1:2, and then the transition metal salt was added in a mass ratio of F to transition metal salt (2-4): 1 and stirred thoroughly at 25°C, and then 20-40 mL of a freshly prepared NaBH4 solution with a concentration of 0.5-3 mg / mL was dropped and stirred evenly, filtered, washed, and vacuum dried at 60°C to obtain a black powder M@F; Step 4: Place M@F in a tube furnace and heat at 200-400°C for 1-3 hours to obtain a solid product M / MO x @F.

2. The method for preparing defect-rich carbon-supported transition metal / metal oxide according to claim 1, characterized in that: The heating temperature in step 1 is 35-45° C. and the heating time is 12-48 hours.

3. The method for preparing defect-rich carbon-supported transition metal / metal oxide according to claim 1, characterized in that: In step 1, the mixed solution is kept at a volume filling ratio of 30% to 70% in the autoclave, the temperature of the autoclave is 100-180° C., and the reaction time is 36-60 hours.

4. The method for preparing defect-rich carbon-supported transition metal / metal oxide according to claim 1, characterized in that: The organic solvent in step 2 is one of monochloronaphthalene, toluene, xylene, mesitylene and isopropylbenzene.

5. The method for preparing defect-rich carbon-supported transition metal / metal oxide according to claim 1, characterized in that: The protective gas in step 2 is one of argon, nitrogen and ammonia.

6. The method for preparing defect-rich carbon-supported transition metal / metal oxide according to claim 1, characterized in that: The salt in the transition metal salt in step 3 is one or a combination of nitrates, sulfates, chlorides and organic complexes of metals, and the metal in the transition metal salt is one or a combination of ruthenium, platinum, palladium, iron, cobalt and nickel.

7. The defect-rich carbon-supported transition metal / metal oxide prepared by the preparation method according to any one of claims 1 to 6, characterized in that: Synthetic M / MO x The electrocatalytic material structure of @F is that metal particles are anchored on defect-rich carbon F, and the applied potential is between M and MO during HER and OER. x Reversibly shuttles between active sites, M and MO x The synergistic effect between them ensures the good catalytic activity of the catalyst.

8. Use of a defect-rich carbon-supported transition metal / metal oxide in a bifunctional water electrolysis catalyst according to claim 7.

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