CN109852992A

CN109852992A - Water nano-chip arrays electrode and its preparation method and application is decomposed in a kind of efficient electro-catalysis entirely

Info

Publication number: CN109852992A
Application number: CN201910075847.9A
Authority: CN
Inventors: 张兴旺; 郝少云; 陈鲁川; 雷乐成
Original assignee: Zhejiang University ZJU
Current assignee: Zhejiang University ZJU
Priority date: 2019-01-25
Filing date: 2019-01-25
Publication date: 2019-06-07
Anticipated expiration: 2039-01-25
Also published as: CN109852992B

Abstract

The invention discloses a high-efficiency electrocatalytic total water splitting nano-sheet array electrode and a preparation method and application thereof. The method takes nickel foam as a substrate and utilizes the method of chloride ion corrosion to prepare an electrode material with an ultrathin nanosheet array morphology. By controlling the concentration of chloride ions and adding metal ion species, the composition of different metals in polyhydroxides can be effectively regulated. The Ni ₅ Co ₃ Mo-OH electrode with the ultrathin nanosheet array morphology of the present invention exhibits excellent electrochemical catalytic water splitting performance for hydrogen production (η ₁₀ =52mV) and oxygen production performance (η ₁₀₀ =304mV). Meanwhile, the material can run stably for 100 h under the condition of 100 mA cm ^-2 , with excellent electrochemical stability. In addition, Ni ₅ Co ₃ Mo‑OH can be used as both cathode and anode for the total water splitting reaction, and the voltage is 1.43 V under the condition of 10 mA·cm ^‑2 current density. We believe that this patent provides a new idea for the preparation of multi-metal hydroxide nanosheet arrays, and at the same time promotes the development of multi-metal hydroxide applications in catalysis and energy.

Description

A kind of efficient electro-catalysis decompose full water nano-chip arrays electrode and preparation method thereof and Using

Technical field

The present invention relates to the systems that electrochemistry decomposes water technical field more particularly to more metal hydroxides nano-chip arrays entirely Preparation Method and its high-efficiency electrochemical decompose water application entirely.

Background technique

It is considered as a kind of environmental-friendly energy storage and the skill utilized that electrochemistry, which decomposes water entirely and generates hydrogen and oxygen, Art.The best material of the aqueous energy of electrochemical decomposition is Pt/C, IrO at present₂And RuO₂Equal noble metal catalysts.However noble metal its The problems such as expensive price and weak stability, so that these electrodes higher cost in industrial application, to limit it Large-scale application in practice.Non-noble metallic materials, such as transition metal nitride, transition metal oxide, transition metal Hydroxide and perovskite oxide can effectively catalyze water and generate hydrogen and oxygen, be expected to replace in electrochemical decomposition water field For precious metal material.However, the activity and margin of stability due to these materials are formed on certain work pH range, as two Application of electrode has certain challenge in total moisture solution.In addition, using unifunctional catalyst respectively as anode and cathode It requires corresponding different production technology and equipment, causes the increase of production cost.Therefore, it develops same under alkaline condition When have the excellent double-function catalyzing electrode for producing hydrogen and producing oxygen performance there is important application value.

In numerous transition metal electrodes, the hydroxide nano chip arrays based on foam nickel electrode are due to more Active site, biggish active area, do not use the advantages that adhesive at faster electron transport rate, it is considered to be Yi Zhongyou Different full decomposition water material.Such as the third metal is introduced into bimetallic Ni-Co or Ni-Mo double-hydroxide and forms ternary Ni-Co-M or Ni-Fe-M catalyst can improve its electrocatalysis characteristic.Although having more document to more metal hydroxides It is studied, but for the excellent difunctional hydroxide nano chip arrays for decomposing aqueous energy and electrochemical stability entirely Research remains unchanged deficient.

In addition, the method for preparing more metal hydroxides nanometer sheets at present is mostly co-electrodeposition method, hydrothermal synthesis method, ion friendship Change method and Fe⁺³Corrosion engineering method etc..However, since most of synthetic method is by synthesis temperature, anionic type and conjunction At the influence of pH.Therefore, can only be used to synthesize double-metal hydroxide or three metal hydroxides.Such as stratiform emerging at present Double-hydroxide (LDH) must contain trivalent metal ion and bivalent metal ion, and synthesize by stringent metal ratio, because This limits the diversity of more metal hydroxides, to limit the development of more metal hydroxides.In conclusion lacking at present A kind of method for preparing multicomponent and adjustable more metal hydroxides nano-chip arrays of weary mild simplicity.

When metal surface forms electrolyte layer, it may occur that galvanic interaction corrodes.In corrosion process, chlorine Ion plays important role.This is because chloride ion can be adsorbed on metal surface more easily, to destroy its inertia Protective layer, so that electrolyte layer is promoted to be formed, accelerated corrosion reaction.Under humid conditions, the oxygen in air and water are in yin Pole is reduced generation hydroxyl, and metal hydroxides is then generated in conjunction with the metal ion of anode.Numerous researchs cause at present For power in how to prevent the metal reaction that is not corroded from being destroyed, this research then utilizes corrosion reaction, is transformed into a kind of mildly making The method of standby more metal hydroxides nano-chip arrays electrodes.

Summary of the invention

Problem to be solved by this invention is just to provide the mild chloride ion quarter corrosion made of metal of one kind and divides entirely for efficient The method for solving water nano-chip arrays electrode, realizes that more metal hydroxide components are controllable, and passes through the ternary of synthesis Ni₅Co₃Mo-OH nano-chip arrays bifunctional electrodes material improves electro-catalysis and produces hydrogen and produce oxygen performance, realizes and decompose answering for water entirely With.And a kind of good idea and method is provided for the preparation of other more metal hydroxides nano-chip arrays electrodes.

To achieve the goals above, the present invention mainly adopts the following technical scheme that,

A kind of preparation method that water nano-chip arrays electrode is decomposed in efficient electro-catalysis entirely includes the following steps: in high concentration cl At least one metal salt and nickel foam are added in solion；Control pH≤6 of initial reaction liquid；It is carried out under aerobic conditions anti- It answers, obtains efficient electro-catalysis total moisture solution electrode, the concentration of the halide ion in the high concentration halide ion solution is greater than 50 mMs every liter.

Preferably, the nickel foam further includes pre-treatment step before being reacted, the pre-treatment step are as follows: Foam nickel base is pre-processed by acid and solvent, removes the oxide layer on surface, nickel foam that treated drying is spare.

Preferably, the metal salt added in Chloride Solution is preferably two or more.

Preferably, the metal salt is metal halide salt, metal nitrate, metal sulfate, metal acetate salt；It is described Metal salt metal cation redox potential be less than nickel ion.

Preferably, the concentration range of metal ion is greater than 0.5 mM every liter.

Water electrode is decomposed entirely the invention also discloses the efficient electro-catalysis produces hydrogen, production oxygen or full decomposition in efficient electro-catalysis Application in water.The electrode is applied to hydrogen producing as the cathode of three-electrode system, and anode is applied to produce oxygen, Huo Zhezuo It is applied to full decomposition water for the working electrode of bipolar electrode system.

Preferably, the step 1) foam nickel base is having a size of 2 × 2cm²。

Preferably, the step 1) concentration of hydrochloric acid is 1M；Hydrochloric acid, acetone and ethyl alcohol difference ultrasound 15min.

Preferably, the reaction condition are as follows: water bath with thermostatic control shaking table temperature is 30 DEG C, revolving speed 150rpm, and when reaction is a length of 12h。

A kind of Ni has been prepared using the above method in the present invention₅Co₃Mo-OH/ foamed nickel electrode material.

Using the electrochemical workstation of three-electrode system, Ni₅Co₃For Mo-OH/ nickel foam as working electrode, graphite rod is pair Electrode, saturation Ag/AgCl are reference electrode, and electrolyte is 1M KOH solution, and 50 milliliters of 1M KOH solutions are added in electrolytic cell, Constant potential+10mAcm^-2Oxygen is collected under current density；-10 mA·cm^-2Hydrogen is collected under current density.

Bipolar electrode system, Ni are taken in full decomposition water reaction₅Co₃Mo-OH/ nickel foam carries out electricity respectively as anode and cathode It is catalyzed total moisture solution.Electrolyte is 50 milliliters of 1M KOH solutions, Ni₅Co₃The work area of Mo-OH/ nickel foam is respectively 1cm², In constant potential+10mAcm^-2Oxygen is collected under current density；-10mA·cm^-2Hydrogen is collected under current density.

The present invention utilizes chloride ion corrosion nickel foam, and is reacted using the electrochemical corrosion in Process of Metallic Corrosion, The Co added in the metal cation Ni and solution of generation on cathode, Mo ion are shifted and are produced to anode jointly Raw OH^-It reacts, generates NiCoMo-OH nano-chip arrays.Electro-chemical test shows in 1M KOH solution, without fixed The trimetallic catalyst Ni of type₅Co₃Mo-OH shows superior Hydrogen Evolution Performance (in -10mAcm^-2It is excessively electric under current density Gesture is 52mV), meanwhile, analysis oxygen performance is also very good (in+10mAcm^-2Overpotential under current density is 304mV).Also, Ni₅Co₃Mo-OH is in+100 and -100mAcm^-2It can stablize respectively 100 hours under current density.Based on Ni₅Co₃Mo-OH Good liberation of hydrogen and analysis oxygen performance, we are by Ni₅Co₃Mo-OH is applied to bipolar electrode system, Ni₅Co₃Mo-OH is in+10mAcm^-2Voltage under current density is only 1.43V.In 100mAcm^-2It can continue to keep 100 hours good steady under current density It is qualitative.The performance is electro-catalysis effect best in the hydroxide reported at present.

Compared with the existing technology, the invention has the following advantages that

1. synthesis technology is simple, reaction condition is mild, catalysis electrode by the method one-step synthesis by chloride ion corrosion, Simplify process flow.

2. synthetic method can regulate and control nanometer sheet component.Pass through species of metal ion and dense in control reaction solution Degree, can be generated more metal hydroxides nanometer sheets of different component, extends the type of more metal hydroxides nanometer sheets.

3. electrode prepared by has excellent H2-producing capacity ((η₁₀=52mV) and production oxygen performance (η₁₀₀=304mV).Together When the material in 100mAcm^-2Under the conditions of can be with stable operation 100h.

4. electrode prepared by has difunctional electro catalytic activity.It is anti-that full decomposition water is carried out as cathode and anode simultaneously It answers, in 10mAcm^-2Voltage is only 1.43V under density conditions.

Detailed description of the invention

Fig. 1 is nano-chip arrays electrode material formation mechenism figure in embodiment 1.

The pattern picture of the nickel foam for the blank that Fig. 2-1, which is embodiment 1, to be obtained by scanning electron microscope；

Obtained nano-chip arrays under the conditions of the different chlorine ion concentrations that Fig. 2-2, which is embodiment 1, to be obtained by scanning electron microscope The pattern picture of electrode；

The pattern of obtained nano-chip arrays electrode under the condition of different pH that Fig. 3, which is embodiment 2, to be obtained by scanning electron microscope Picture；

Fig. 4 is that embodiment 2 passes through X-ray photoelectron spectroscopic analysis Ni₅Co₃Mo-OH nano-chip arrays element valence and each The interaction of element；

Fig. 5-1 is to obtain Ni by transmission electron microscope in embodiment 3₅Co₃Mo-OH nano-chip arrays pattern and distribution diagram of element；

Fig. 5-2 is Ni in embodiment 3₅Co₃Mo-OH nano-chip arrays application of electrode produces the polarization curve of oxygen in anode；

Fig. 5-3 is Ni in embodiment 3₅Co₃Mo-OH nano-chip arrays application of electrode produces the polarization curve of hydrogen in cathode；

Fig. 5-4 is Ni in embodiment 3₅Co₃The current versus time curve of Mo-OH nano-chip arrays electrode stability test；

Fig. 6-1 is Ni in embodiment 4₅Co₃Mo-OH nano-chip arrays application of electrode is in the performance test figure for decomposing water entirely；

Fig. 6-2 is Ni in embodiment 4₅Co₃Mo-OH nano-chip arrays application of electrode is in the stability test figure for decomposing water entirely；

Fig. 7 is that embodiment 5 is obtained by scanning electron microscope through nanometer sheet prepared by regulation metal ion component and type The pattern picture of array electrode.

Specific embodiment

Embodiment 1

Nano-chip arrays formation mechenism is as follows: in primary battery anode region, high concentration Cl^-Solution can strengthen corrosion, will Nickel foam is oxidized to Ni²⁺, subsequent Cl^-It can constantly migrate to anode region and constantly be enriched with, as shown in formula 1；Water and sky simultaneously Oxygen reaction in gas, is reduced to hydroxyl (OH in cathode zone^-), as shown in formula 2；Final metal ions M^x+With Ni²⁺ In conjunction in foam nickel surface and OH^-Reaction generates more metal hydroxides nano-chip arrays, as shown in formula 3.Its mechanism figure is such as Shown in Fig. 1.According to this mechanism, implement following experiment.

Cathode:O₂+2H₂O+4e^-→4OH^- (2)

Ni²⁺+M^x++(2+x)OH^-→Ni-M-OH_2+x (3)

It will be having a size of 2 × 2cm²Foam nickel base (thickness 1mm), be successively 1M hydrochloric acid, acetone and anhydrous second with concentration Alcohol is cleaned by ultrasonic 15 minutes, removes the oxide on surface.Electrode surface liquid is dried up with argon gas, is put into spare in hermetic bag.It is logical The pattern picture of the nickel foam for the blank that overscanning Electronic Speculum obtains is as shown in Fig. 2-1.The nickel foam of blank has 3 D pore canal knot Structure, smooth surface.

Prepare reaction solution, liquor capacity 50mL.Reaction solution NaCl, CoCl₂·6H₂O and MoCl₅It forms, wherein NaCl Concentration is respectively 5mM, 50mM, 500mM and 1000mM, CoCl₂·6H₂O concentration is 0.5mM, MoCl₅Concentration is 0.5mM.Solution Initial pH value is adjusted to 3.5 by 1M hydrochloric acid.It is to be added anti-in 100mL conical flask that the nickel foam handled well, which is put into volume, Solution is answered, and is sealed with preservative film.Reactor is placed in water bath with thermostatic control shaking table and is reacted.Water bath with thermostatic control shaking table temperature is 30 DEG C, revolving speed 150rpm, when reaction a length of 12h.Prepared nano-chip arrays electrode uses deionization after taking out in reactor After water and ethyl alcohol are respectively washed three times, are dried up and saved with argon gas.Electrode is made under the conditions of various concentration chloride ion can be obtained such as Fig. 2-2 Shape appearance figure.It can be obtained from the figure that not observing a nanometer chip architecture under low chlorine ion concentration conditions；With chlorine ion concentration by Cumulative height is grown into out nanometer chip architecture.

Embodiment 2

Referring to the electrode preparation method of embodiment 1, more metal hydroxides nanometer sheets are prepared under the conditions of different initial pH Electrode.Reaction solution initial pH value is adjusted by 1M hydrochloric acid, is adjusted to 2,3.5,5.5 respectively.NaCl concentration is in reaction solution 0.5M, remaining reaction condition are same as Example 1.Prepared electrode in reactor after taking out, with deionized water and ethyl alcohol After being respectively washed three times, is dried up and saved with argon gas.As Fig. 3 can obtain obtained more metal hydroxides under the conditions of different initial pH Shape appearance figure.It can be obtained by Fig. 3, occur nanometer chip architecture in acid condition, and pH value is lower, nanometer chip size is bigger, Quantity is more.

Embodiment 3

Referring to 1 the method for embodiment, NaCl concentration is 0.5M in reaction solution, under conditions of initial pH is 3.5, Ni is prepared₅Co₃Mo-OH nano-chip arrays electrode.Fig. 4 is to pass through X-ray photoelectron spectroscopic analysis Ni₅Co₃Mo-OH receives The valence state of the rice each element of chip arrays electrode.Fig. 5-1 is the Ni as obtained by scanning electron microscope and transmission electron microscope₅Co₃Mo-OH electrode Pattern and distribution diagram of element.It can be obtained from the figure that resulting materials have nano-chip arrays structure, and each element is evenly distributed on and receives In rice chip architecture.Fig. 5-2 shows the material in 10mAcm^-2Under density conditions, the overpotential for producing hydrogen is respectively 52mV.Fig. 5-3 Show the material in 100mAcm^-2Under density conditions, the overpotential for producing oxygen is respectively 304mV.Fig. 5-4 shows that the material exists 100mA·cm^-2Under density conditions, electrochemical stability with higher.

Embodiment 4

Ni will be prepared in example 3₅Co₃Mo-OH nano-chip arrays use bipolar electrode body as electrode in 1M KOH solution It is the full decomposition water performance test carried out and stability test.It can be obtained by Fig. 6-1, the material is in 10mAcm^-2Density conditions Lower voltage is only 1.43V；Meanwhile can be obtained by Fig. 6-2, in 10mAcm^-2And 100mAcm^-2It is continually and steadily transported under current density Row 100 hours.

Embodiment 5

Referring to 1 the method for embodiment, change different metal ions type and concentration in reaction solution, to more metal hydrogen-oxygens The component and pattern of compound are regulated and controled.For monometallic Ni (OH)₂The preparation of nanometer sheet, reaction solution, which is changed to concentration, is The NaCl and concentration of 0.5M is the NiCl of 0.5mM₂·6H₂O.Reaction solution is changed to dense by the preparation for double-metal hydroxide The CoCl that degree is 0.5M NaCl and concentration is 0.5mM₂·6H₂O.Preparation for more metal hydroxides, in the double gold of preparation (i.e. NaCl (0.5M) and CoCl on the basis of the reaction solution of category oxide₂·6H₂O (0.5/n mM)), it is separately added into FeCl₃· 6H₂O, CuCl₂·2H₂O,MoCl₅,MnCl₂·4H₂O, and ZnCl₂, concentration is 0.5/n mM, and n represents the type of metal.Such as Fig. 7, which can be obtained, obtains the pattern and distribution diagram of element of different more metal hydroxides by scanning electron microscope and transmission electron microscope.It can by figure , different metal salting liquid produces nanometer sheet, and element is evenly distributed in nanometer chip architecture.

Embodiment 6

Referring to 1 the method for embodiment, change the anionic type of different metal salt in reaction solution, to more metal hydrogen-oxygens The component and pattern of compound are regulated and controled.Preparation for double-metal hydroxide, it is 0.5M that reaction solution, which is changed to concentration, Co (the NO that NaCl and concentration are 0.5mM₃)·6H₂O.Preparation for more metal hydroxides nanometer sheets, is preparing bimetallic (i.e. NaCl (0.5 M) and Co (NO on the basis of the reaction solution of oxide nano-slice₃)·6H₂O (0.5/n mM)), it is separately added into Fe(NO₃)₃·9H₂O,Mn(CH₃COO)₂·4H₂O, and Zn (CH₃COO)₂·2H₂O, concentration are 0.5/n mM, and n represents metal Type.

Claims

1. a preparation method of high-efficiency electrocatalytic water-splitting nanosheet array electrode is characterized in that comprising the steps: adding at least one metal salt and nickel foam in high-concentration chloride ion solution; controlling the pH≤6 of initial reaction solution The reaction is carried out under aerobic conditions to obtain a high-efficiency electrocatalytic total water splitting electrode, and the concentration of the halogen ions in the high-concentration halogen ion solution is greater than 50 millimoles per liter.

2. The preparation method according to claim 1, characterized in that the nickel foam further comprises a pretreatment step before the reaction, and the pretreatment step is: pretreating the nickel foam substrate by an acid and a solvent, Remove the oxide layer on the surface, and blow dry the treated nickel foam for use.

3. The preparation method according to claim 1, wherein the metal salt added in the chloride ion solution is preferably two or more.

4. preparation method according to claim 1 or 3 is characterized in that described metal salt is metal halide salt, metal nitrate, metal sulfate, metal acetate; The oxidation of the metal cation of described metal salt The reduction potential is lower than that of nickel ions.

5. The preparation method according to claim 1, wherein the concentration range of metal ions is greater than 0.5 mmol per liter.

6. An efficient electrocatalytic total water splitting nanosheet array electrode prepared by the method of claim 1.

7 . The electrode according to claim 6 , wherein the prepared high-efficiency electrocatalytic water-splitting nanosheet array electrode has a nanosheet array morphology, and the thickness of the nanosheet is 2-30 nm. 8 .

8. The application of the high-efficiency electrocatalytic total water splitting electrode of claim 6 in high-efficiency electrocatalytic hydrogen production, oxygen production or total water splitting.

9 . The application according to claim 8 , wherein the electrode is used as the cathode of the three-electrode system for hydrogen production, the anode is used for the production of oxygen, or as the working electrode of the two-electrode system for total water splitting. 10 .