CN111686812B - Ligand-activated transition metal layered dihydroxy compound, preparation method and application - Google Patents

Ligand-activated transition metal layered dihydroxy compound, preparation method and application Download PDF

Info

Publication number
CN111686812B
CN111686812B CN201910189114.8A CN201910189114A CN111686812B CN 111686812 B CN111686812 B CN 111686812B CN 201910189114 A CN201910189114 A CN 201910189114A CN 111686812 B CN111686812 B CN 111686812B
Authority
CN
China
Prior art keywords
ldh
transition metal
ligand
negative ions
activated
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201910189114.8A
Other languages
Chinese (zh)
Other versions
CN111686812A (en
Inventor
杨世和
龙霞
王亚琼
王政
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Peking University Shenzhen Graduate School
Original Assignee
Peking University Shenzhen Graduate School
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Peking University Shenzhen Graduate School filed Critical Peking University Shenzhen Graduate School
Priority to CN201910189114.8A priority Critical patent/CN111686812B/en
Publication of CN111686812A publication Critical patent/CN111686812A/en
Application granted granted Critical
Publication of CN111686812B publication Critical patent/CN111686812B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
    • B01J31/16—Catalysts comprising hydrides, coordination complexes or organic compounds containing coordination complexes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/30—Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
    • B01J35/33—Electric or magnetic properties
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/02—Hydrogen or oxygen
    • C25B1/04—Hydrogen or oxygen by electrolysis of water
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/36—Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/10—Process efficiency
    • Y02P20/133—Renewable energy sources, e.g. sunlight

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Inorganic Chemistry (AREA)
  • Electrochemistry (AREA)
  • Metallurgy (AREA)
  • Catalysts (AREA)

Abstract

The invention relates to the technical field of new energy and electrocatalysis materials, and discloses a preparation method of a ligand-activated transition metal layered double hydroxide compound (TM LDH). The preparation method uses sodium borohydride to activate the hydroxyl ligand of TM LDH to become TM LDH activated by hydride, and can also use Cl ‑ Negative ion, br ‑ Negative ion, I ‑ And further activating one or more of negative ions, N-containing negative ions, P-containing negative ions or S-containing negative ions. The invention also discloses the prepared ligand-activated TM LDH and application thereof, and a water-splitting anode and a water-splitting three-electrode system which take the ligand-activated TM LDH as a catalyst. The water decomposition anode is applied to the electrolysis of water, and compared with the traditional foamed nickel electrode, the water decomposition anode shows lower overpotential and Tafel slope, greatly improves the water decomposition capability and reduces the cost of hydrogen production by water decomposition.

Description

Ligand-activated transition metal layered dihydroxy compound, preparation method and application
Technical Field
The invention relates to the technical field of new energy and electrocatalysis materials, in particular to a preparation method of a ligand-activated transition metal layered dihydroxy compound, the prepared ligand-activated transition metal layered dihydroxy compound and application thereof, and a water-splitting anode and a water-splitting three-electrode system containing the ligand-activated transition metal layered dihydroxy compound.
Background
The global energy shortage and the aggravation of the environmental pollution problem make the demand for clean and renewable energy more and more urgent. Hydrogen has the advantages of high energy density, no pollution of combustion products and the like, and is considered to be one of the most ideal green energy sources capable of replacing fossil fuels. The existing methods for preparing hydrogen mainly comprise natural gas steam conversion hydrogen production, methanol cracking hydrogen production and water decomposition hydrogen production. The hydrogen production by natural gas steam conversion and the hydrogen production by methanol cracking need to use natural gas or methanol fuel as raw materials, and more importantly, the product contains more impurities such as carbon dioxide, carbon monoxide, methane and the like besides hydrogen. The hydrogen production by water decomposition has the advantages of high efficiency, simple process and high purity of reaction products. The first group standard of hydrogen energy field in China, namely' fuel hydrogen for proton exchange membrane fuel cell (T/CECA-G0015-2017), has strict requirements on the purity of hydrogen, the volume fraction of the hydrogen is more than or equal to 99.99%, and the hydrogen with the purity can only be prepared by water decomposition.
The hydrogen production by water decomposition is to prepare hydrogen by decomposing water by electricity or light, and the chemical reaction formula is 2H 2 0→2H 2 +O 2 . The reaction process includes a cathodic Hydrogen Evolution Reaction (HER) and an anodic Oxygen Evolution Reaction (OER). The reaction kinetics of the anode oxygen production reaction is very slow, and the process of hydrogen production by water decomposition is greatly limited. The price of hydrogen production by water electrolysis is higher than that of hydrogen production by natural gas steam conversion and hydrogen production by methanol cracking at present. Therefore, the development of the efficient and cheap water decomposition catalyst, the reduction of the energy barrier of the OER reaction and the reduction of the energy consumption required by hydrogen production through water decomposition are of great importance for the large-scale preparation of high-purity hydrogen, the development of new energy, the promotion of the development of fields such as hydrogen energy automobiles and the like and the alleviation of environmental pollution.
Layered Double Hydroxide (LDH) is composed of a positively charged main plate layer formed by metal ions and hydroxyl ligands and interlayer anions for charge compensation, wherein the species and molar ratio of the metal ions in the main plate layer are adjustable within a certain range, and the interlayer anions can be changed by ion exchange. Transition metal-based layered double hydroxide (TM LDH) is an LDH in which metal ions in the main plate layer are transition metal ions. In recent years, the application of TM LDH in the field of hydrogen production by water decomposition has been greatly developed. The catalytic oxygen production activity and stability of the TM LDH are close to those of a noble metal oxygen production catalyst iridium oxide (IrO) 2 ) And ruthenium oxide (RuO) 2 ). While non-noble metals such as transition metal reservoirs on earthThe water-splitting catalyst is rich in quantity, so that the non-noble metal water-splitting catalyst such as TM LDH has larger application potential compared with a noble metal catalyst.
The TM LDH may be optimized to further improve its catalytic performance. Optimization is typically achieved by adjusting the type and molar ratio of transition metal ions (see, e.g., SCI paper published by the inventor's topic group in 2015: co integral processed formation of organic nanoparticles of transition metal LDH-An advanced electrolyte for Oxygen Evolution Reaction, chemical Communications 51 (6), decumber 2014), or by changing the interlayer anions of TM LDH (see, e.g., SCI paper published by the inventor's topic group in 2014: A Structure Coupled product and FeNi Double Hydroxide electrolyte An electrolyte for the Oxygen Evolution Reaction, international electrolyte Chemical Edition in experiment 53, J2014).
The optimization can effectively regulate and control the electronic structure of transition metal ions playing a catalytic role, the conductivity of the catalyst and the micro morphology such as the interlayer spacing, the specific surface area and the like of TM LDH, thereby effectively optimizing the catalytic performance of the transition metal-based water splitting catalyst. However, due to the limitation of the atomic structure of the layered dihydroxy compound, the optimization of the species of the transition metal ions can only be selected from a limited number of elements, the optimization of the molar ratio of the transition metal ions can only be performed in a limited range, and the interlayer anions are far away from the transition metal ions for catalysis, and only the interlayer spacing and thus the specific surface area of the water-splitting catalyst can be changed to a certain extent.
However, modification of hydroxyl ligands attached to transition metal ions has not been reported.
Disclosure of Invention
The invention aims to modify and activate a hydroxyl ligand of a transition metal layered double hydroxyl compound (TM LDH) to obtain a ligand-activated TM LDH which can be used as a catalyst for an oxygen production reaction in a water splitting reaction to improve the hydrogen production performance by water splitting.
Accordingly, a first aspect of the invention provides a process for the preparation of a ligand-activated TM LDH, the process comprising the steps of:
(1) Uniformly dispersing TM LDH in a polar solvent to obtain a TM LDH suspension, wherein the transition metal is any combination of divalent and trivalent transition metal ions;
(2) And (2) adding sodium borohydride with appropriate amount for activation reaction into the suspension obtained in the step (1) to carry out activation reaction, so as to obtain the ligand activated TM LDH.
In a preferred embodiment of the first aspect of the present invention, the atomic ratio of the divalent/trivalent transition metal ion is between (3-10): 1, more preferably between (4-8): 1, still more preferably between (5-6): 1.
In a preferred embodiment of the first aspect of the present invention, the transition metal ion is a Ni (II)/Fe (III) combination, a Ni (II)/Mn (III) combination, a Ni (II)/Co (III) combination or a Co (II)/Fe (III) combination, more preferably a Ni (II)/Fe (III) combination.
In a preferred embodiment of the first aspect of the invention, in step (1), the weight to volume ratio of the TM LDH to the polar solvent is (0.5-2) mg:1 ml, more preferably (0.8-1.8) mg:1 ml, still more preferably (1.0-1.5) mg:1 ml.
In a preferred embodiment of the first aspect of the present invention, in step (2), the activation reaction is suitably used in an amount such that the final concentration of the sodium borohydride in the suspension of step (1) is 0.001-0.01M, more preferably, 0.003-0.008M.
In a preferred embodiment of the first aspect of the present invention, the activation reaction is carried out at a reaction temperature of 20 to 80 ℃ for a reaction time of 0.5 to 10 hours, more preferably at a reaction temperature of 40 to 60 ℃ for a reaction time of 1 to 5 hours.
In a preferred embodiment of the first aspect of the present invention, the polar solvent is deionized water or ethanol or a mixed solvent thereof.
In a particularly preferred embodiment of the first aspect of the invention, the preparation process comprises the following specific steps:
(1) Uniformly dispersing Ni (II)/Fe (III), ni (II)/Mn (III), ni (II)/Co (III) or Co (II)/Fe (III) TM LDH with the atomic ratio of (3-10): 1 in deionized water or ethanol or a mixed solvent of the deionized water and the ethanol, wherein the weight-volume ratio of the TM LDH to the polar solvent is (0.5-2) mg:1 ml, and uniformly dispersing by ultrasonic vibration and stirring to obtain a TM LDH suspension;
(2) Adding sodium borohydride with the final concentration of 0.001-0.01M into the suspension obtained in the step (1), stirring and dispersing uniformly at the stirring speed of 400-1000 rpm, then reacting for 0.5-10 hours at the reaction temperature of 20-80 ℃ and at the stirring speed of 700-1000rpm, naturally cooling to room temperature, adding a proper amount of deionized water or absolute ethyl alcohol as a washing solvent, carrying out centrifugal washing three times at 6000-8000 rpm for 5-10 minutes each time, and then carrying out vacuum drying for 3-6 hours to obtain the LDH (layered double hydroxide) activated by the hydride ligand.
In the above-mentioned particularly preferred embodiment of the first aspect of the invention, the weight to volume ratio of the TM LDH to the polar solvent is more preferably (0.8-1.8) mg:1 ml, still more preferably (1.0-1.5) mg:1 ml.
In the above-mentioned specifically preferred embodiment of the first aspect of the present invention, in step (2), the final concentration of sodium borohydride is more preferably 0.003 to 0.008M; the reaction temperature of the reaction is more preferably 40 to 60 ℃ and the reaction time is more preferably 3 to 8 hours.
A second aspect of the invention provides a method of preparing a ligand-activated TM LDH, the method comprising the steps of:
(1) Uniformly dispersing TM LDH in a polar solvent to obtain TM LDH suspension; the transition metal is any combination of divalent and trivalent transition metal ions;
(2) Adding sodium borohydride with proper amount for activation reaction into the suspension obtained in the step (1), and adding Cl with proper amount for activation reaction - Negative ion, br - Negative ion, I - And (3) performing an activation reaction on one or more of negative ions, N-containing negative ions, P-containing negative ions or S-containing negative ions to obtain the ligand activated TM LDH.
In a preferred embodiment of the second aspect of the present invention, the atomic ratio of the divalent/trivalent transition metal ion is between (3-10): 1, more preferably between (4-8): 1, still more preferably between (5-6): 1.
In a preferred embodiment of the second aspect of the present invention, the transition metal ion is a Ni (II)/Fe (III) combination, a Ni (II)/Mn (III) combination, a Ni (II)/Co (III) combination or a Co (II)/Fe (III) combination, more preferably a Ni (II)/Fe (III) combination.
In a preferred embodiment of the second aspect of the invention, in step (1), the weight to volume ratio of the TM LDH to the polar solvent is (0.5-2) mg:1 ml, more preferably (0.8-1.8) mg:1 ml, still more preferably (1.0-1.5) mg:1 ml.
In a preferred embodiment of the second aspect of the present invention, in step (2), the activation reaction is suitably used in an amount such that the final concentration of the sodium borohydride in the suspension of step (1) is 0.001-0.01M, more preferably 0.003-0.008M.
In a preferred embodiment of the second aspect of the present invention, in step (2), the activating reaction is suitably carried out in an amount such that the Cl is present - Negative ion, br - Negative ion, I - The total final concentration of one or more of negative ions, N-containing negative ions, P-containing negative ions or S-containing negative ions in the suspension of step (1) is 0.1-10M, more preferably 1-8M, and still more preferably 3-6M.
In a preferred embodiment of the second aspect of the invention, the activation reaction is carried out at a reaction temperature of 20 to 80 ℃ for a reaction time of 0.5 to 10 hours, more preferably at a reaction temperature of 40 to 60 ℃ for a reaction time of 1 to 5 hours.
In a preferred embodiment of the second aspect of the present invention, the polar solvent is deionized water or ethanol or a mixed solvent thereof.
In a particularly preferred embodiment of the second aspect of the invention, the preparation process comprises the following specific steps:
(1) Uniformly dispersing Ni (II)/Fe (III), ni (II)/Mn (III), ni (II)/Co (III) or Co (II)/Fe (III) TM LDH with the atomic ratio of (3-10): 1 in deionized water or ethanol or a mixed solvent of the deionized water and the ethanol, wherein the weight-volume ratio of the TM LDH to the polar solvent is (0.5-2) mg:1 ml, and uniformly dispersing by ultrasonic vibration and stirring to obtain a TM LDH suspension;
(2) Adding sodium borohydride to the suspension of step (1) to a final concentration of 0.001-0.01M and adding the Cl to a total final concentration of 0.1-10M - Negative ion, br - Negative ion, I - One or more of negative ions, negative ions containing N, negative ions containing P or negative ions containing S is/are uniformly stirred and dispersed at the stirring speed of 400-1000 rpm, then the mixture reacts at the reaction temperature of 20-80 ℃ and the stirring speed of 700-1000rpm for 0.5-10 hours, after the mixture is naturally cooled to room temperature, a proper amount of deionized water or absolute ethyl alcohol is added as a washing solvent, the mixture is centrifugally washed at 6000-8000 rpm for three times, each time for 5-10 minutes, and then the mixture is dried in vacuum for 3-6 hours, so that the ligand activated LDH TM is obtained.
In the above particularly preferred embodiments of the second aspect of the invention, the weight to volume ratio of the TM LDH to the polar solvent is more preferably (0.8-1.8) mg:1 ml, still more preferably (1.0-1.5) mg:1 ml.
In the above-mentioned specifically preferred embodiment of the second aspect of the present invention, in step (2), the final concentration of the sodium borohydride is more preferably from 0.003 to 0.008M; the Cl - Negative ion, br - Negative ion, I - The total final concentration of one or more of the negative ions, N-containing negative ions, P-containing negative ions, or S-containing negative ions in combination is more preferably 1 to 8M, still more preferably 3 to 6M; the reaction temperature of the reaction is more preferably 40 to 60 ℃ and the reaction time is more preferably 3 to 8 hours.
In the second aspect of the present invention, the N-containing anion, the P-containing anion or the S-containing anion is preferably NSC - 、SCN - 、CN - 、NH 3 、PO 3 3- 、PO 4 3- And the like.
A third aspect of the invention provides a ligand-activated TM LDH prepared by the preparation method according to the first or second aspect of the invention.
The ligand-activated TM LDH prepared according to the preparation method of the first aspect of the present invention is a hydride (H) ion - ) Activated TM LDH.
The ligand-activated TM LDH prepared according to the preparation method of the second aspect of the present invention isChloride anion (Cl) - ) Bromine anion (Br) - ) Iodine anion (I) - ) A TM LDH activated by a combination of one or more of nitrogen (N) -containing anions, phosphorus (P) -containing anions, and sulfur (S) -containing anions.
A fourth aspect of the invention provides the use of the ligand-activated TM LDH of the third aspect of the invention as an oxygen-producing catalyst for water-splitting anodes.
A fifth aspect of the invention provides a water-splitting anode comprising a foamed nickel, carbon cloth or iron substrate and a ligand-activated TM LDH of the third aspect of the invention coated on the foamed nickel, carbon cloth or iron substrate. The ligand-activated TM LDH serves as an oxygen-producing catalyst for water-splitting anodes.
The water-splitting anode can be prepared as follows. 1-2 mg of the ligand activated TM LDH catalyst is taken and placed in 1 ml of absolute ethyl alcohol, and strong ultrasonic dispersion is carried out to obtain catalyst dispersion liquid. Uniformly mixing 200-500 mu L of prepared catalyst dispersion liquid and 4-8% of PTFE aqueous solution by mass according to the volume ratio of (1-3) to 1, and performing ultrasonic dispersion. And uniformly coating the obtained mixed dispersion liquid on a foamed nickel, carbon cloth or iron substrate, and drying in an oven at 40-70 ℃ for 20-40 minutes.
A sixth aspect of the invention provides a water-splitting three-electrode system comprising a water-splitting anode according to the fifth aspect of the invention, pt wire as a counter electrode, ag/AgCl as a reference electrode and 0.5-1.5M aqueous potassium hydroxide or sodium hydroxide solution as an electrolyte. Preferably, the electrolyte is a 1M aqueous solution of potassium hydroxide or sodium hydroxide.
The invention has the beneficial effects that:
according to the preparation method of the ligand-activated TM LDH, the problem of difficulty in electron transfer between transition metal ions can be solved by activating the hydroxyl ligand directly connected with the transition metal ions, the condition that the electron arrangement of the transition metal ions is not ideal is solved, the optimal arrangement of catalytic active atom electrons is realized, the coordination environment of the transition metal ions is effectively changed, and the synergistic interaction between the metal ions is enhanced.
The TM LDH activated by the ligand prepared by the preparation method can be used as a water decomposition anode catalyst, so that efficient and stable oxygen production is realized, and the hydrogen production performance of the catalyst in water decomposition is improved. The water decomposition anode prepared by the ligand activated TM LDH is applied to the electrolysis of water, and compared with the traditional foam Nickel (NF) electrode, the water decomposition anode shows lower overpotential and Tafel slope, greatly improves the water decomposition capability and reduces the cost of hydrogen production by water decomposition.
Drawings
FIG. 1 is a Scanning Electron Micrograph (SEM) and a Transmission Electron Micrograph (TEM) of a NiFe LDH (A, C, D) prior to sodium borohydride activation and a H-NiFe LDH (B, E, F) after activation according to example 1 of the present invention, wherein (A, B) is the SEM image, (C, E) is the TEM image, and (D, F) is a High Resolution TEM (HRTEM) image;
FIG. 2 is an XRD image of NiFe LDH before and H-NiFe LDH after sodium borohydride activation according to example 1 of the present invention;
FIG. 3 is the preparation of H-NiFe LDH after sodium borohydride activation according to example 1 of the present invention 2 H magic angle spin nuclear magnetic resonance (MAS NMR) plot;
FIG. 4 is a graph of the electrochemical impedance of H-NiFe LDH at 300 mV overpotential after sodium borohydride activation, versus NiFe LDH and H-Ni (OH) in accordance with example 1 of the present invention 2 Carrying out comparison;
FIG. 5 is a schematic structural diagram of a three-electrode system of a test example of the present invention, niFe LDH as a water electrolysis anode catalyst, where 1 denotes a working electrode, 2 denotes a reference electrode, and 3 denotes a counter electrode;
FIG. 6 is a comparative plot of the catalytic hydrogen production polarization curves for foamed nickel, niFe LDH and H-NiFe LDH in accordance with test examples of the present invention;
FIG. 7 is a comparative graph of the catalytic oxygen generation Tafel curves for foamed nickel, niFe LDH and H-NiFe LDH in accordance with the test examples of the present invention;
FIG. 8 is a graph of H-NiFe LDH at 10, 20 and 50 mA cm in accordance with test examples of the present invention -2 The current density of (a) is measured in a chronopotentiometric test graph, wherein the inset is H-NiFe LDH at 50 mA cm -2 A long-time chronopotentiometric test pattern exceeding 12 hours at a current density of (a);
FIG. 9 is a comparative graph of the catalytic hydrogen production polarization curves of NCS-NiFe LDH and NiFe LDH in test examples according to the present invention.
Detailed Description
The present invention will be described in further detail below with reference to specific embodiments and accompanying drawings.
Transition metal layered double hydroxides (TM LDHs) have been extensively studied as one of the most effective oxygen generating reaction (OER) catalysts. However, there is no report on the effect of hydroxyl (-OH) ligands of LDH on OER catalysis. According to the rule of superexchange interaction, electrons can be transferred from one transition metal ion to an adjacent transition metal ion through a non-magnetic anion, so the inventors believe that the electron transfer inside the TM LDH during OER may be affected by hydroxyl ligands octahedrally complexed directly with the transition metal ion, thereby affecting the catalytic performance of the TM LDH. Due to the negative ion of hydrogen (H) - ) Small size and strong complexing ability, so the inventors believe that it can readily react with protons to form one molecule of hydrogen, thus affecting the hydroxyl ligand of TM LDH. To confirm this hypothesis, the inventors used sodium borohydride (NaBH) 4 ) As a source of hydride ions, DFT calculations were performed with the most efficient OER catalyst, niFe LDH, as a typical TM LDH model. The results show that the hydride of sodium borohydride will take one proton from the hydroxyl ligand of NiFe LDH, producing one molecule of H 2 At the same time, a strong B-O σ bond is formed. Since B has an empty p orbital, O has a lone pair of electrons, and the B-O bond has a strong tendency to form a B-O double bond, the hydride can easily migrate to the metal center to form a transition metal-hydride bond (Fe-H or Ni-H), accompanied by the formation of NaBOH 2 Which can further form NaBO 2 。
Since hydride is a strong field ligand, the energy of the reverse bonded d-orbitals of the complexed transition metal ions can be easily increased. The d orbitals of both Fe (III) and Ni (II) are occupied, making NiFe LDH treated with hydride unstable. Therefore, in order to reduce the energy of the system, one electron is transferred from the opposite bonding orbit of Ni (II) to the bonding orbit of Fe (III) via a hydride bridge by super exchange interaction, thereby forming Ni (III) and Fe (II). The present inventors calculated the fermi level partial charge densities of NiFe LDH and H-NiFe LDH in order to understand the influence of the hydride ions, and as a result, found that a higher charge density appears in the region near the activated transition metal ion, indicating that the transition metal ion can be activated by substituting the hydroxyl (-OH) ligand of TM LDH. However, the generated transition metal-hydride ions are close to each other, and a reduction elimination reaction can easily occur, generating hydrogen gas and reducing the transition metal, resulting in the formation of metal nanoparticle decorated LDH. To avoid the reduction of the transition metal, the inventors greatly reduced the concentration of sodium borohydride to 1 mM to obtain a low concentration of transition metal-hydride, while the hydroxyl ligand of the TM LDH can still be substituted for the hydride.
In conclusion, after intensive research, inspired by the super-exchange interaction, the invention discovers that activating the hydroxyl ligand of the TM LDH by using low-concentration sodium borohydride can influence electron transfer, adjust the coordination condition of transition metal ions, and influence the surface physical and chemical properties of the transition metal ions, thereby influencing the catalytic performance of the TM LDH. Taking NiFe LDH as an example, activation of the hydroxyl ligand causes electrons to be transferred from Ni (II) in a low oxidation state to Fe (III) in a high oxidation state via a hydrogen ion bridge via superexchange interaction, thereby generating OER activity Ni (III), resulting in an improvement in OER performance of NiFe LDH, with the Ni (III) concentration being proportional to OER performance. NiFe with hydroxyl ligands and hydrogen ion ligands in activated NiFe LDH 4 The unit is a catalytically active center in which Ni sites serve as absorption/desorption sites, while adjacent Fe ions accumulate electrons through superexchange interactions. In addition to NiFe LDH, the present inventors found that TM LDHs such as NiMn LDH, niCo LDH, and CoFe LDH also have the same effect. Furthermore, in addition to the activation of the hydroxyl ligands of the TM LDH by the hydrogen anions, the Cl ions may be used further - Negative ion, br - Negative ion, I - The negative ions, N-containing negative ions, P-containing negative ions or S-containing negative ions activate the hydroxyl ligands of the TM LDH.
Thus, the present inventors have developed a method for the preparation of a ligand-activated TM LDH, the prepared ligand-activated TM LDH and its use, as well as a water-splitting anode and a water-splitting three-electrode system comprising the ligand-activated TM LDH, as described in the summary of the invention section above. Among them, the present inventors found that the concentration of sodium borohydride, the reaction temperature and the reaction time are important in the preparation method of the ligand-activated TM LDH of the present invention. When the concentration of sodium borohydride is higher, the transition metal ions are reduced into corresponding metal nano particles, so that the catalytic action is reduced. The water bath temperature is too low or the reaction time is too short, the ligand activation is difficult to carry out or is incomplete, and the catalytic action is not ideal; and the water bath temperature is too high or the reaction time is too long, the reduction is excessive, and the catalytic action is not ideal.
The invention is illustrated by the following non-limiting examples.
Example 1: synthesis and characterization of hydride activated NiFe LDH catalyst (H-NiFe LDH)
1.1 Synthesis of NiFe LDH
NiFe LDH nano powder is synthesized by a hydrothermal method, and the specific operation is as follows. 0.725 ml of 1M nickel chloride (NiCl) was added in a beaker 2 ) Aqueous solution and 0.145 ml of 1M iron chloride (FeCl) 3 ) The aqueous solution was mixed with 70.8 ml of deionized water. Then 5.6 ml of 0.5M aqueous urea solution and 2 ml of 0.01M aqueous trisodium citrate solution were added to the beaker with magnetic stirring. Then the obtained mixed solution is transferred into a stainless steel pressure cooker with 100 ml of polytetrafluoroethylene lining, and after sealing, hydrothermal reaction is carried out in an oven with the temperature of 150 ℃ for 24 hours. After the reaction, the mixture is centrifuged at 7500 rpm for 10 minutes to collect powder, then the powder is washed by deionized water and high-purity ethanol for several times and then dried in an oven with the temperature of 50 ℃ overnight to prepare NiFe LDH nano powder which is a Ni (II)/Fe (III) transition metal layered dihydroxy compound.
1.2 Synthesis of H-NiFe LDH catalyst
Adding 1 mg of the NiFe LDH powder prepared in the above step into 10 ml of deionized water in a 15 ml sealed bottle, and preparing a NiFe LDH suspension by ultrasonic vibration at the vibration frequency of 50 KHz and uniformly stirring and dispersing at the stirring speed of 800 rmp. Adding 1.9 mg NaBH into a sealed bottle 4 Stirring and dispersing evenly at the stirring speed of 500 rpm to obtain NaBH 4 The final concentration was 0.005M. Placing the sealed bottle in a 50 ℃ water bath kettle, and reacting for 2 hours at a stirring speed of 800 rpm. After the reaction, the reaction mixture was naturally cooled to room temperature, 5 ml of deionized water was added to the beaker to dilute the reaction mixture, and the diluted solution was transferred to a 10 ml centrifuge tube and washed by centrifugation at 7000 rpm for 10 minutes. The supernatant was discarded and centrifuged again twice in the same manner. And (3) drying the final precipitate for 5 hours in vacuum at the pressure of-100 KPa relative to the atmospheric pressure to obtain the H-NiFe LDH catalyst.
1.3 Characterization of hydride activated NiFe LDH (H-NiFe LDH) catalyst
FIG. 1 shows the present example in NaBH 4 Scanning electron microscopy images (SEM) and transmission electron microscopy images (TEM) of NiFe LDH (a, C, D) before activation and H-NiFe LDH (B, E, F) after activation, where (a, B) is SEM image, (C, E) is TEM image, and (D, F) is High Resolution TEM (HRTEM). It can be seen that the nanostructure of NiFe LDH was maintained after sodium borohydride treatment.
FIG. 2 shows the present example in NaBH 4 XRD images of the NiFe LDH before activation and the H-NiFe LDH after activation show the same characteristic diffraction peak, and show that the crystalline phase is unchanged and the crystallinity is high.
FIG. 3 shows the present example in NaBH 4 Method for producing activated H-NiFe LDH 2 H magic angle spin nuclear magnetic resonance (MAS NMR) pattern, showing the formation of H-M bonds, indicating the activation and substitution of hydroxyl ligands in H-NiFe LDH.
FIG. 4 shows the present example in NaBH 4 Electrochemical impedance plot of activated H-NiFe LDH at 300 mV overpotential, with NiFe LDH and H-Ni (OH) 2 And (6) carrying out comparison. As can be seen from FIG. 4, naBH 4 The H-NiFe LDH catalyst had the lowest resistance after activation, indicating that the catalyst had the best electron conductivity.
Among them, H-Ni (OH) for comparison 2 Synthesized as follows. Firstly, ni (OH) is synthesized by a hydrothermal method 2 The specific operation is as follows. 0.87 ml of 1M nickel chloride (NiCl) 2 ) The aqueous solution was mixed with 70.8 ml of deionized water in a beaker. Then 5.6 ml of 0.5M aqueous urea solution and 2 ml of 0.01M aqueous trisodium citrate solution were added to the beaker with magnetic stirring. The resulting mixed solution was then transferred to a 100 ml teflon-lined stainless steel cylinderAnd (4) sealing in a pressure cooker, and carrying out hydrothermal reaction in a drying oven at 150 ℃ for 24 hours. After the reaction, the powder was collected by centrifugation at 7500 rpm for 10 minutes, then washed several times with deionized water and high-purity ethanol, and then dried overnight in a 50 ℃ oven to obtain Ni (OH) 2 . Then, H-Ni (OH) was prepared in a similar manner to 1.2 2 。
Example 2: synthesis of hydride activated NiMn LDH catalyst (H-NiMn LDH)
2.1 Synthesis of NiMn LDH
NiMn LDH nano powder is synthesized by a hydrothermal method, and the specific operation is as follows. 0.435 ml of 1M nickel chloride (NiCl) was added in a beaker 2 ) Aqueous solution and 0.145 ml of 1M manganese chloride (MnCl) 2 ) The aqueous solution was mixed with 70 ml of deionized water. 4.48 ml of a 0.5M aqueous urea solution and 1.6 ml of a 0.01M aqueous trisodium citrate solution are then added to the beaker under magnetic stirring. Then the obtained mixed solution is transferred into a stainless steel pressure cooker with 100 ml of polytetrafluoroethylene lining, and after sealing, hydrothermal reaction is carried out in an oven with the temperature of 150 ℃ for 24 hours. After the reaction, the mixture is centrifuged at 7500 rpm for 10 minutes to collect powder, then the powder is washed by deionized water and high-purity ethanol for several times, and then the powder is dried in a 50 ℃ oven overnight to prepare NiMn LDH nano powder which is a Ni (II)/Mn (III) transition metal layered dihydroxy compound.
2.2 Synthesis of H-NiMn LDH catalyst
0.5 mg of the NiMn LDH powder prepared above was added to 1 ml of deionized water in a 15 ml sealed bottle, and a NiMn LDH suspension was prepared by ultrasonic vibration at an amplitude of 50 KHz and uniformly dispersed with stirring at a stirring speed of 800 rmp. Add 3.8 mg NaBH to sealed bottle 4 Stirring and dispersing evenly at the stirring speed of 500 rpm to obtain NaBH 4 The final concentration was 0.001M. The sealed bottle was placed in a water bath at 80 ℃ and reacted at a stirring speed of 800 rpm for 10 hours. After the reaction, the reaction mixture was naturally cooled to room temperature, 5 ml of deionized water was added to the beaker to dilute the reaction mixture, and the diluted solution was transferred to a 20 ml centrifuge tube and washed by centrifugation at 7000 rpm for 10 minutes. The supernatant was discarded and centrifuged again twice in the same manner. Subjecting the final precipitate to a pressure relative to atmospheric pressureAnd (5) drying for 5 hours under the pressure of-100 KPa to obtain the H-NiMn LDH catalyst.
Example 3: synthesis of hydride activated NiCo LDH catalyst (H-NiCo LDH)
3.1 Synthesis of NiCo LDH
NiCo LDH nano powder is synthesized by a hydrothermal method, and the specific operation is as follows. 1.16 ml of 1M nickel chloride (NiCl) was placed in a beaker 2 ) Aqueous solution and 0.145 ml of 1M cobalt chloride (CoCl) 2 ) The aqueous solution was mixed with 70 ml of deionized water. Then 10.1 ml of 0.5M aqueous urea solution and 1.1 ml of 0.01M aqueous trisodium citrate solution were added to the beaker with magnetic stirring. The resulting mixed solution was then transferred to a 100 ml teflon-lined stainless steel autoclave and sealed and subjected to hydrothermal reaction in a 150 ℃ oven for 24 hours. After the reaction, the powder is collected by centrifugation at 7500 rpm for 10 minutes, then washed with deionized water and high-purity ethanol for several times, and then dried in a 50 ℃ oven overnight to prepare NiCo LDH nano powder which is a Ni (II)/Co (III) transition metal layered dihydroxy compound.
3.2 Synthesis of H-NiCo LDH catalyst
1.5 mg of NiCo LDH powder prepared as described above was put into 10 ml of anhydrous ethanol in a 15 ml sealed bottle, and a NiCo LDH suspension was prepared by ultrasonic vibration at an amplitude of 50 KHz and uniformly dispersed with stirring at a stirring speed of 800 rmp. Adding 3 mg NaBH into a sealed bottle 4 Stirring and dispersing evenly at the stirring speed of 500 rpm to obtain NaBH 4 The final concentration was 0.008M. The sealed bottle was placed in a 30 ℃ water bath and reacted at a stirring speed of 800 rpm for 5 hours. After the reaction, the reaction mixture was naturally cooled to room temperature, and 5 ml of absolute ethanol was added to the beaker to dilute the reaction mixture, and the diluted solution was transferred to a 20 ml centrifuge tube and washed by centrifugation at 7000 rpm for 10 minutes. The supernatant was discarded and centrifuged again twice in the same manner. And (3) drying the final precipitate for 5 hours in vacuum at the pressure of-100 KPa relative to the atmospheric pressure to obtain the H-NiCo LDH catalyst.
Example 4: synthesis of hydride activated CoFe LDH catalyst (H-CoFe LDH)
4.1 Synthesis of CoFe LDH
CoFe LDH nanopowder was synthesized by a hydrothermal method, specifically as follows. 0.145 ml of 1M cobalt chloride (CoCl) was placed in a beaker 2 ) Aqueous solution and 1.45 ml of 1M iron chloride (FeCl) 3 ) The aqueous solution was mixed with 70 ml of deionized water. Then 11.2 ml of 0.5M aqueous urea solution and 4 ml of 0.01M aqueous trisodium citrate solution were added to the beaker with magnetic stirring. The resulting mixed solution was then transferred to a 100 ml teflon-lined stainless steel autoclave and sealed and subjected to hydrothermal reaction in a 150 ℃ oven for 24 hours. After the reaction, the mixture is centrifuged at 7500 rpm for 10 minutes to collect powder, then the powder is washed by deionized water and high-purity ethanol for several times, and then the powder is dried in a 50 ℃ oven overnight to prepare CoFe LDH nano powder which is a Co (II)/Fe (III) transition metal layered dihydroxy compound.
4.2 Synthesis of H-CoFe LDH catalyst
2 mg of the CoFe LDH powder prepared above was added to 10 ml of anhydrous ethanol in a 15 ml sealed bottle, and a CoFe LDH suspension was prepared by ultrasonic vibration at an amplitude of 50 KHz and uniformly dispersed with stirring at a stirring speed of 800 rmp. Add 3.8 mg NaBH to sealed bottle 4 Stirring and dispersing evenly under the stirring speed of 500 rpm to obtain NaBH 4 The final concentration was 0.01M. The sealed bottle was placed in a 60 ℃ water bath and reacted at a stirring speed of 800 rpm for 0.5 hour. After the reaction was completed, the reaction mixture was naturally cooled to room temperature, and 5 ml of absolute ethanol was added to the beaker to dilute the reaction mixture, and the diluted solution was transferred to a 20 ml centrifuge tube and centrifuged at 7000 rpm for 10 minutes. The supernatant was discarded and centrifuged again twice in the same manner. And (3) drying the final precipitate for 5 hours in vacuum at the pressure of-100 KPa relative to the atmospheric pressure to obtain the H-CoFe LDH catalyst.
Example 5: synthesis of NiFe LDH catalyst (Cl-NiFe LDH) activated by chlorine anion
5.1 Synthesis of NiFe LDH
NiFe LDH nanopowders were synthesized as in 1.1 of example 1.
5.2 Synthesis of NiFe LDH catalyst activated by chlorine anion
1 mg of NiFe LDH powder prepared as described above was added to a 15 ml sealNiFe LDH suspension was prepared by ultrasonic vibration at 50 KHz amplitude and stirring at 800 rmp in 10 ml deionized water in a flask. Adding 1.9 mg NaBH into a sealed bottle 4 And 584 mg of sodium chloride is added to be stirred and dispersed evenly at the stirring speed of 500 rpm to obtain NaBH 4 A final concentration of 0.005M and a final concentration of Cl-1M. The sealed bottle was placed in a 50 ℃ water bath and reacted for 5 hours at a stirring speed of 800 rpm. After the reaction, the reaction mixture was naturally cooled to room temperature, 5 ml of deionized water was added to the beaker to dilute the reaction mixture, and the diluted solution was transferred to a 20 ml centrifuge tube and washed by centrifugation at 7000 rpm for 10 minutes. The supernatant was discarded and centrifuged again twice in the same manner. And (3) drying the final precipitate for 5 hours in vacuum at the pressure of-100 KPa relative to the atmospheric pressure to obtain the Cl-NiFe LDH catalyst.
Example 6: synthesis of bromine anion activated NiFe LDH catalyst (Br-NiFe LDH)
This example was carried out in the same manner as in example 5 except that sodium chloride was replaced with sodium bromide so that the final concentration of Br-in the reaction solution was 1M, to finally obtain a Br-NiFe LDH catalyst.
Example 7: synthesis of NiFe LDH catalyst (I-NiFe LDH) activated by iodide anion
This example was carried out in the same manner as in example 5 except that sodium chloride was replaced with sodium iodide so that the final concentration of I-in the reaction solution was 1M, to finally obtain an I-NiFe LDH catalyst.
Example 8: synthesis of NiFe LDH catalyst (N-NiFe LDH) activated by nitrogen anions
This example was carried out in the same manner as in example 5 except that potassium isothiocyanate (NCS) was used in place of sodium chloride so that the final concentration of N in the reaction solution was 1M, to finally obtain an N-NiFe LDH catalyst.
Example 9: synthesis of NiFe LDH catalyst (P-NiFe LDH) activated by phosphorus negative ion
This example was carried out in the same manner as in example 5 except that sodium chloride was replaced with sodium phosphate so that the final concentration of P in the reaction solution was 1M, to finally obtain a P-NiFe LDH catalyst.
Example 10: synthesis of NiFe LDH catalyst (S-NiFe LDH) activated by sulfur anion
This example was carried out in the same manner as in example 5 except that potassium thiocyanate was used in place of sodium chloride so that the final concentration of S in the reaction solution was 1M, to finally obtain an S-NiFe LDH catalyst.
Example 11: preparation of catalyst/foamed nickel electrode
The foamed nickel was immersed in 1M HCl solution for 10 minutes to remove surface oxides, then washed several times with deionized water and ethanol, and dried in an oven at 60 ℃ for future use. 1 mg of the H-NiFe LDH catalyst synthesized in example 1 was ultrasonically and uniformly dispersed in 1 ml of ethanol for 2 hours to obtain a catalyst dispersion. Uniformly mixing 500 uL of prepared catalyst dispersion liquid with 5% of PTFE aqueous solution according to the volume ratio of 2. And uniformly coating the obtained mixed dispersion liquid on a piece of foamed nickel (1 cm x 1 cm), and drying in an oven at the temperature of 60 ℃ for 30 minutes to obtain the H-NiFe LDH catalyst/foamed nickel electrode.
Electrodes can be prepared in a similar manner on carbon cloth or iron substrates using the H-NiFe LDH catalyst prepared in example 1. Also, electrodes can be prepared in a similar manner on foamed nickel, carbon cloth or iron substrates using the catalysts prepared in examples 2-10.
Test example: water decomposition catalytic performance of H-NiFe LDH catalyst
Using the H-NiFe LDH catalyst/foamed nickel electrode prepared in example 11 as a water-splitting anode (working electrode), pt wire as a counter electrode, ag/AgCl as a reference electrode, and 1M aqueous potassium hydroxide solution as an electrolyte, a water-splitting three-electrode system was constructed, as shown in FIG. 5, in which reference numeral 1 denotes the working electrode, 2 denotes the reference electrode, and 3 denotes the counter electrode. A NiFe LDH catalyst/foamed nickel electrode was prepared in the same manner as in example 11, and a water-splitting three-electrode system having the NiFe LDH catalyst/foamed nickel electrode as a working electrode was constructed in the same manner as in this test example. In addition, a water-splitting three-electrode system having a foamed nickel electrode as a working electrode was constructed in the same manner as in this test example.
The three water splitting three-electrode systems constructed above were tested on an EC-lab (Bio-Logic) and a Chi electrochemical workstation (Shanghai Chenghua) to verify the water splitting catalytic performance of the H-NiFe LDH catalyst of the present invention. FIG. 6 shows a comparative plot of the catalytic hydrogen production polarization curves for foamed nickel, niFe LDH and H-NiFe LDH. As can be seen from fig. 6, the activated H-NiFe LDH catalyst has the lowest overpotential, indicating that the same current density is achieved with the lowest energy consumption. FIG. 7 shows a comparative graph of catalytic oxygen production tafel curves for foamed nickel, niFe LDH and H-NiFe LDH. As can be seen from fig. 7, the H-NiFe LDH catalyst after ligand activation has the lowest tafel slope, representing the fastest oxygen producing reaction rate.
The stability of H-NiFe LDH was tested by chronopotentiometry. FIG. 8 is a graph showing H-NiFe LDH at 10, 20 and 50 mA cm -2 The current density of (a) is measured in a chronopotentiometric test graph, wherein the inset is H-NiFe LDH at 50 mA cm -2 A long-time chronopotentiometric test pattern exceeding 12 hours at a current density of (1). As can be seen from FIG. 8, the catalyst after ligand activation has good stability and industrial application prospect.
In addition, an NCS-NiFe LDH catalyst/nickel foam electrode was also prepared in the same manner as in example 10 using the NCS-NiFe LDH catalyst prepared in example 8, and compared with the H-NiFe LDH catalyst/nickel foam electrode prepared in example 11 in the same operation as in this test example. FIG. 9 shows a comparative plot of the catalytic hydrogen production polarization curves for NCS-NiFe LDH and NiFe LDH. As can be seen in FIG. 9, the activated NCS-NiFe LDH catalyst has the lowest overpotential, similar to H-NiFe LDH, indicating that the same current density is achieved with the lowest energy consumption.
The present invention has been described above using specific examples, which are only for the purpose of facilitating understanding of the present invention, and are not intended to limit the present invention. Numerous simple deductions, modifications or substitutions may be made by those skilled in the art in light of the teachings of the present invention. Such deductions, modifications or alternatives also fall within the scope of the claims of the present invention.

Claims (7)

1. A preparation method of a ligand-activated transition metal layered dihydroxy compound is characterized by comprising the following steps:
(1) Uniformly dispersing a transition metal layered dihydroxy compound in a polar solvent to form a transition metal layered dihydroxy compound suspension, wherein the transition metal is any combination of divalent and trivalent transition metal ions; the atomic ratio of the divalent/trivalent transition metal ions is (3-10): 1; the transition metal ion is a Ni (II)/Fe (III) combination, a Ni (II)/Mn (III) combination, a Ni (II)/Co (III) combination or a Co (II)/Fe (III) combination;
(2) Adding sodium borohydride with proper amount for activation reaction into the suspension obtained in the step (1), and adding Cl with proper amount for activation reaction - Negative ion, br - Negative ion, I - And (3) carrying out activation reaction on one or more of negative ions, N-containing negative ions, P-containing negative ions or S-containing negative ions to obtain the ligand-activated transition metal layered dihydroxy compound.
2. The preparation method according to claim 1, wherein in the step (1), the weight-to-volume ratio of the transition metal layered double hydroxide compound to the polar solvent is (0.5-2) mg:1 mL; in the step (2), the appropriate amount of the activation reaction is such that the final concentration of the sodium borohydride in the suspension of the step (1) is 0.001-0.01M, and the Cl is - Negative ion, br - Negative ion, I - The total final concentration of one or more of negative ions, negative ions containing N, negative ions containing P or negative ions containing S in the suspension liquid in the step (1) is 0.1-10M, the reaction temperature of the activation reaction is 20-80 ℃, and the reaction time is 0.5-10 hours.
3. The preparation method according to claim 1, comprising the following specific steps:
(1) Uniformly dispersing Ni (II)/Fe (III), ni (II)/Mn (III), ni (II)/Co (III) or Co (II)/Fe (III) transition metal layered dihydroxy compounds with the atomic ratio of (3-10): 1 in deionized water or ethanol or a mixed solvent of the deionized water and the ethanol, wherein the weight-volume ratio of the transition metal layered dihydroxy compounds to the polar solvent is (0.5-2) mg:1 mL, and uniformly dispersing by ultrasonic vibration and stirring to obtain transition metal layered dihydroxy compound suspension;
(2) Adding sodium borohydride with final concentration of 0.001-0.01M into the suspension obtained in the step (1), and adding the Cl with total final concentration of 0.1-10M - Negative ion, br - Negative ion, I - One or more of negative ions, negative ions containing N, negative ions containing P or negative ions containing S is/are uniformly stirred and dispersed at a stirring speed of 400-1000 rpm, then the mixture reacts at a reaction temperature of 20-80 ℃ and a stirring speed of 700-1000rpm for 0.5-10 hours, after the mixture is naturally cooled to room temperature, a proper amount of deionized water or absolute ethyl alcohol is added as a washing solvent, the mixture is centrifugally washed at 6000-8000 rpm for three times, each time for 5-10 minutes, and then vacuum drying is carried out for 3-6 hours, so as to obtain the ligand-activated transition metal layered dihydroxy compound.
4. A ligand-activated transition metal layered dihydroxy compound, characterized in that it is prepared by the preparation method according to any one of claims 1 to 3.
5. Use of the ligand-activated transition metal layered dihydroxy compound of claim 4 as an oxygen production catalyst for water-splitting anodes.
6. A water-splitting anode comprising a foamed nickel, carbon cloth, or iron substrate and the ligand-activated transition metal layered bishydroxy compound according to claim 4 coated on the foamed nickel, carbon cloth, or iron substrate.
7. A water-splitting three-electrode system comprising the water-splitting anode of claim 6, pt wire as a counter electrode, ag/AgCl as a reference electrode, and 0.5-1.5M aqueous potassium hydroxide or sodium hydroxide solution as an electrolyte.
CN201910189114.8A 2019-03-13 2019-03-13 Ligand-activated transition metal layered dihydroxy compound, preparation method and application Active CN111686812B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201910189114.8A CN111686812B (en) 2019-03-13 2019-03-13 Ligand-activated transition metal layered dihydroxy compound, preparation method and application

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201910189114.8A CN111686812B (en) 2019-03-13 2019-03-13 Ligand-activated transition metal layered dihydroxy compound, preparation method and application

Publications (2)

Publication Number Publication Date
CN111686812A CN111686812A (en) 2020-09-22
CN111686812B true CN111686812B (en) 2023-04-07

Family

ID=72474961

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201910189114.8A Active CN111686812B (en) 2019-03-13 2019-03-13 Ligand-activated transition metal layered dihydroxy compound, preparation method and application

Country Status (1)

Country Link
CN (1) CN111686812B (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112501650B (en) * 2020-11-06 2021-12-28 北京大学深圳研究生院 Multi-vacancy transition metal layered dihydroxy compound, preparation method and application
CN113941327B (en) * 2021-11-23 2024-03-19 江苏科技大学 Palladium-based catalyst and preparation method and application thereof

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103143376A (en) * 2013-03-29 2013-06-12 北京化工大学 High-activity hydrotalcite loaded gold nanocluster catalyst and preparation method thereof

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090148484A1 (en) * 2007-12-07 2009-06-11 National Taiwan University Stably-dispersing composite of metal nanoparticle and inorganic clay and method for producing the same
CN101665233B (en) * 2009-09-15 2012-06-06 北京化工大学 Layered double hydroxide and preparation method thereof
RO129990A0 (en) * 2013-11-19 2015-01-30 Chimigaz Srl Hydrotalcite-based catalyst for hydrogenation of fatty acid esters and process for preparing the same
WO2016096990A1 (en) * 2014-12-19 2016-06-23 Basf Se Process for the preparation of oxide materials, layered double hydroxide materials, hydroxide materials and carbonate-based materials
EP3384070B1 (en) * 2015-11-30 2023-04-19 NewSouth Innovations Pty Limited Method for improving catalytic activity
US20170362522A1 (en) * 2016-06-21 2017-12-21 Ecoedge Technology, LLC. Concentration of sodium borohydride as electrolyte for the generation of hydrogen as fuel in diesel and gasoline internal combustion engines with a catalyst system using minimum current
GB201703558D0 (en) * 2017-03-06 2017-04-19 Univ Oxford Innovation Ltd catalysts

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103143376A (en) * 2013-03-29 2013-06-12 北京化工大学 High-activity hydrotalcite loaded gold nanocluster catalyst and preparation method thereof

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
过渡金属基层状双羟基化合物的调控及其在电化学水氧化中的应用;龙霞等;《应用化学》(第08期);第32-40页 *

Also Published As

Publication number Publication date
CN111686812A (en) 2020-09-22

Similar Documents

Publication Publication Date Title
Li et al. Rational design of porous Ni-Co-Fe ternary metal phosphides nanobricks as bifunctional electrocatalysts for efficient overall water splitting
Liu et al. Defect-rich (Co, Fe) 3O4 hierarchical nanosheet arrays for efficient oxygen evolution reaction
CN110129815B (en) Modified TM-LDH nano material, preparation method and application thereof
Jiang et al. Synthesis of g-C3N4/Fe3O4/MoS2 composites for efficient hydrogen evolution reaction
Chen et al. High-performance bifunctional Fe-doped molybdenum oxide-based electrocatalysts with in situ grown epitaxial heterojunctions for overall water splitting
Wei et al. Fabrication of Co doped MoS2 nanosheets with enlarged interlayer spacing as efficient and pH-Universal bifunctional electrocatalyst for overall water splitting
CN110575836B (en) Pt-loaded Fe-doped alpha-phase nickel hydroxide nanosheet array material, and preparation method and application thereof
Ye et al. Oxygen vacancies and surface reconstruction on NiFe LDH@ Ni (OH) 2 heterojunction synergistically triggering oxygen evolution and urea oxidation reaction
Chang et al. Research progress in improving the oxygen evolution reaction by adjusting the 3d electronic structure of transition metal catalysts
Wang et al. Tuning the electronic structure of NiSe2 nanosheets by Mn dopant for hydrogen evolution reaction
Gu et al. Cobalt fluoride/nitrogen-doped carbon derived from ZIF-67 for oxygen evolution reaction
Yang et al. Prussian blue analogue assisted formation of iron doped CoNiSe2 nanosheet arrays for efficient oxygen evolution reaction
An et al. Mo, Fe-codoped metal phosphide nanosheets derived from Prussian blue analogues for efficient overall water splitting
Chen et al. P-doped MOF-derived CoNi bimetallic sulfide electrocatalyst for highly-efficiency overall water splitting
CN111686812B (en) Ligand-activated transition metal layered dihydroxy compound, preparation method and application
Wang et al. Interface engineering and heterometal-doped FeOOH/Ga-Ni 3 S 2 nanosheet arrays for efficient electrocatalytic oxygen evolution
Yang et al. V2O3/FeOOH with rich heterogeneous interfaces on Ni foam for efficient oxygen evolution reaction
Jin et al. Atomic-level tungsten doping triggered low overpotential for electrocatalytic water splitting
CN112501650B (en) Multi-vacancy transition metal layered dihydroxy compound, preparation method and application
Hu et al. The importance of the iron valence state in NiCoFe nanosheet array catalysts for the oxygen evolution reaction
Wu et al. Hierarchical core-shell structural Ni2P/NiMoO4@ CoP/FeP2 nanorods as difunctional electrocatalysts for efficient overall water splitting
Du et al. Boosting alkaline water splitting and the urea electrolysis kinetic process of a Co 3 O 4 nanosheet by electronic structure modulation of F, P co-doping
Wang et al. Porphyrin coordination polymer supported transition-metal sulfides as precious-metal-free electrocatalysts for efficient overall water splitting
Zheng et al. NiCoP-nanocubes-decorated CoSe2 nanowire arrays as high-performance electrocatalysts toward oxygen evolution reaction
Zhu et al. Sea Urchin–Like CoS2@ WS2/NF Bifunctional Catalyst for Efficient Overall Water Splitting

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant