1. One-dimensional nanowire Na_0.7MnO₂@Na_0.91MnO₂The preparation method of the @ MnOS composite material is characterized by comprising the following steps of:

1) mixing KMnO₄Glucose and H₂Mixing O, carrying out a first hydrothermal reaction, washing, settling and drying a reactant, and calcining in an oxygen atmosphere to obtain manganese oxide;

2) mixing manganese oxide and a sodium hydroxide aqueous solution for a second hydrothermal reaction, and washing and drying a reactant to obtain a manganese oxide nanowire;

3) respectively putting the manganese oxide nano-wire and the sublimed sulfur into two porcelain boats, calcining in a tube furnace under the nitrogen atmosphere to obtain the one-dimensional nano-wire Na_0.7MnO₂@Na_0.91MnO₂@ MnOS composite material.

2. The method for preparing a composite material according to claim 1, wherein: KMnO₄And grapeThe feeding mass ratio of the sugar is 1: 1.

3. The method for preparing a composite material according to claim 1, wherein: the first hydrothermal reaction temperature is 150-160 ℃, and the reaction time is 10 hours.

4. The method for preparing a composite material according to claim 1, wherein: in the step 1), the drying condition is 100 ℃ and the time is 12 hours.

5. The method for preparing a composite material according to claim 1, wherein: during the calcination in the step 1), the temperature is increased to 500-600 ℃ at the heating rate of 5 ℃/min, and then the calcination is carried out for 6 h.

6. The method for preparing a composite material according to claim 1, wherein: the second hydrothermal reaction temperature is 200-210 ℃, and the reaction time is 84-120 hours.

7. The method for preparing a composite material according to claim 1, wherein: the feeding molar mass ratio of the manganese oxide to the sodium hydroxide in the sodium hydroxide aqueous solution is 1: 100.

8. The method for preparing a composite material according to claim 1, wherein: and 3) introducing nitrogen from one end of the tubular furnace, discharging the nitrogen from the other end of the tubular furnace, placing the ceramic boat containing the sublimed sulfur at the upstream of the flow direction of the nitrogen, and placing the ceramic boat containing the manganese oxide nanowires at the downstream of the flow direction of the nitrogen.

9. The method for preparing a composite material according to claim 1, wherein: in the step 3), the temperature in the tube furnace is increased to 350-500 ℃ at the heating rate of 2 ℃/min, and then the heat preservation and calcination are carried out for 3 h.

10. A method for preparing a composite material according to claim 1 or 8 or 9, characterized in that: the feeding mass ratio of the manganese oxide nanowires to the sublimed sulfur is 1: 1.

Background

It is well known that the most widely used active electrode materials at present are conductive polymers, carbon, and noble and transition metal oxides. Among these candidate materials, transition metal oxides stand out for their excellent characteristics. MnO in various transition metal oxides in comparison with other transition metal oxide systems₂And its derivatives are considered to be the most attractive electrochemical capacitor materials because of their advantages of low cost, high quantity, environmental friendliness, etc.

The structural size, the grain size, the specific surface area and the morphology of the material of the electrode material have important influence on the electrochemical performance, however, the ordered nanowire array with high specific surface area provides a promising path for further improving the electrochemical performance of the electrode material. Transition metal oxides (e.g. NiO, MnO)₂、Co₃O₄And CuCo₂O₄) Transition metal hydroxide (Ni (OH))₂) And transition metal sulfide (Ni)₃S₂、NiCo₂S₄) Due to its unique properties, it finds wide application in electrochemical energy storage and conversion. Element doping and structural modification are two aspects of improving electrochemical performance. The dopant is added to adjust the surface electron intensity by changing the electron-donating-accepting tendency between the substrate atoms and the doping atoms, thereby improving the redox capability of the electrode material.

Due to excellent stability, diversified structure, unique physicochemical characteristics and huge specific surface area, the one-dimensional manganese oxide nanowire is applied to the fields of photoelectron catalysis, energy storage, lithium batteries, sensors, selective adsorption and the like. The nano-structure with different shapes such as nano-wire, nano-sheet and nano-sphere is obtained by a plurality of synthesis methods such as common sol-gel, reflux and hydrothermal treatment. However, there are few reports on the synthesis of one-dimensional multivalent manganese oxide and related sulfide composites. Therefore, it is of great significance to further find an efficient and controllable synthesis method.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a method for efficiently preparing one-dimensional nanowires Na_0.7MnO₂@Na_0.91MnO₂@ MnOS composite material.

The invention comprises the following steps:

1) mixing KMnO₄Glucose and H₂Mixing O, carrying out a first hydrothermal reaction, washing, settling and drying a reactant, and calcining in an oxygen atmosphere to obtain manganese oxide;

2) mixing manganese oxide and a sodium hydroxide aqueous solution for a second hydrothermal reaction, and washing and drying a reactant to obtain a manganese oxide nanowire;

3) respectively putting the manganese oxide nano-wire and the sublimed sulfur into two porcelain boats, calcining in a tube furnace under the nitrogen atmosphere to obtain the one-dimensional nano-wire Na_0.7MnO₂@Na_0.91MnO₂@ MnOS composite material.

Step 1) manganese carbonate is obtained through oxidation reduction under hydrothermal conditions, and a manganese oxide black solid is obtained after calcination.

And 2) obtaining the nanowire material through a series of changes of the shape under the hydrothermal condition, wherein the nanowire material is easy to synthesize, high in reaction yield, large in length-diameter ratio, and easy to disperse in an aqueous medium under the auxiliary condition of tidal generation to form a stable colloidal solution.

And 3) reacting the sublimed sulfur gas with the nanowire composite material through nitrogen flow, and performing a series of reactions with the material to obtain the composite material due to certain reducibility of sulfur.

The invention adopts a hydrothermal method and a low-temperature calcination method, so that the crystallinity is high and the particle size is uniform; and the method has the advantages of simple process, low reaction temperature and short time, and is suitable for batch production.

Further, to reduce waste and obtain samples required for high yield, the KMnO of the present invention₄The feeding mass ratio of the glucose to the raw materials is 1: 1.

In order to further widen the flexibility of the reaction and obtain the required material in a controllable range, the temperature of the first hydrothermal reaction is 150-160 ℃, and the reaction time is 10 hours.

In the step 1), the drying condition is 100 ℃ and the time is 12 hours. The condition can meet the requirement that the required dry material can be obtained in a short time in the practical application process so as to be better applied to the next reaction.

During the calcination in the step 1), the temperature is increased to 500-600 ℃ at the heating rate of 5 ℃/min, and then the calcination is carried out for 6 h. The condition can obtain the product required by design under the condition of higher efficiency.

In order to obtain the material required by the design, the second hydrothermal reaction temperature is 200-210 ℃, and the reaction time is 84-120 hours.

In order to obtain the required manganese oxide nano wire, the feeding molar mass ratio of the manganese oxide to the sodium hydroxide in the sodium hydroxide aqueous solution is 1: 100.

And 3) introducing nitrogen from one end of the tubular furnace, discharging the nitrogen from the other end of the tubular furnace, placing the ceramic boat containing the sublimed sulfur at the upstream of the flow direction of the nitrogen, and placing the ceramic boat containing the manganese oxide nanowires at the downstream of the flow direction of the nitrogen. This arrangement is advantageous for better reaction of the sublimed sulphur with the material along with the nitrogen flow.

In the step 3), the temperature in the tube furnace is increased to 350-500 ℃ at the heating rate of 2 ℃/min, and then the heat preservation and calcination are carried out for 3 h. The setting program can obtain the composite material required by design on the basis of maintaining the original appearance.

The feeding mass ratio of the manganese oxide nanowires to the sublimed sulfur is 1: 1. The setting program can obtain the substances required by the design under the condition of meeting the safety requirement.

Drawings

Fig. 1 is an SEM image of a one-dimensional manganese oxide nanowire material before sulfidation.

FIG. 2 shows one-dimensional nano-wire Na vulcanized at 350 deg.C_0.7MnO₂@Na_0.91MnO₂@ MnOS SEM image of composite material.

FIG. 3 shows the one-dimensional nano-wire Na vulcanized under the condition of 400 DEG C_0.7MnO₂@Na_0.91MnO₂@ MnOS SEM image of composite material.

FIG. 4 shows the one-dimensional nano-wire Na vulcanized under the condition of 500 DEG C_0.7MnO₂@Na_0.91MnO₂@ MnOS SEM image of composite material.

FIG. 5 shows the one-dimensional nano-wire Na vulcanized under the condition of 350 DEG C_0.7MnO₂@Na_0.91MnO₂The XPS full spectrum of the @ MnOS composite material.

FIG. 6 shows the one-dimensional nano-wire Na vulcanized under the condition of 400 DEG C_0.7MnO₂@Na_0.91MnO₂The XPS full spectrum of the @ MnOS composite material.

FIG. 7 shows the one-dimensional nano-wire Na vulcanized under the condition of 500 DEG C_0.7MnO₂@Na_0.91MnO₂The XPS full spectrum of the @ MnOS composite material.

FIG. 8 shows one-dimensional nanowires Na synthesized by sulfurization at 350 deg.C and 500 deg.C_0.7MnO₂@Na_0.91MnO₂The XRD pattern of @ MnOS composite.

Detailed Description

Firstly, preparing one-dimensional nano-wire Na_0.7MnO₂@Na_0.91MnO₂@ MnOS composite Material:

(1) 78.9 mg of KMnO₄And 2 g of glucose are put into 15-30 ml of deionized water, after ultrasonic dispersion, the mixture is transferred into a reaction kettle, hydrothermal reaction is carried out for 10 hours at the temperature of 150-160 ℃, then deionized water and ethanol are adopted for repeated cleaning for 3 times, and drying is carried out for 12 hours at the temperature of 100 ℃ to obtain the manganese carbonate.

(2) Manganese carbonate with random mass is put into a porcelain boat (the mass of a sample calcined in the step is based on that a thin layer is fully paved on the whole porcelain boat), the temperature is increased to 500-600 ℃ at the temperature rising rate of 5 ℃/min under the air condition, and then the temperature is preserved for 6 hours to obtain Mn₂O₃Black powder.

(3) 0.0789 g Mn₂O₃Adding black powder into 10 ml of 5 mol/L sodium hydroxide aqueous solution, and allowing Mn to react under ultrasonic condition₂O₃Completely dispersing black powder in a sodium hydroxide aqueous solution, then placing the mixed system in a reaction kettle at 200-210 DEG CCarrying out hydrothermal reaction for 84-120 hours under the condition, then respectively washing for 3 times by adopting water and ethanol, and then carrying out freeze drying to obtain the manganese oxide nanowire.

(4) Placing a ceramic boat containing 20 mg of sublimed sulfur at the upstream of gas and a ceramic boat containing 20 mg of manganese oxide nanowires at the downstream of the gas in a tube furnace, raising the temperature in the tube furnace to 350-500 ℃ at the initial temperature of 20 ℃ at the temperature rise rate of 2 ℃/min under the condition of introducing nitrogen, and then keeping the temperature for calcining for 3 hours to obtain the one-dimensional nanowires Na_0.7MnO₂@Na_0.91MnO₂@ MnOS composite material.

Secondly, the composite material is detected by a Scanning Electron Microscope (SEM), and the result is as follows:

fig. 1, 2, 3 and 4 show that the one-dimensional manganese oxide nanowire material before vulcanization, the composite material obtained by vulcanization at 350 ℃, 400 ℃ and 500 ℃ are nanowire morphologies, dense small particles are generated on the surface at a lower temperature, no particles are generated on the surface of the nanowire at 400 ℃ and a small amount of large particles are generated on the surface of the nanowire at 500 ℃.

This also indicates that the lower the temperature the better, and that there is no better morphology retention above 500 ℃.

Thirdly, carrying out XPS full spectrum on the composite material, and obtaining the following results:

FIGS. 5, 6 and 7 show that the composite materials obtained by calcination under different temperature conditions all have three elements of Mn, O, S and the like, which illustrates the successful incorporation of the element S.

Fourthly, carrying out X-ray diffraction (XRD) detection on the composite material, wherein the result is as follows:

FIG. 8 shows almost no hetero-peaks, indicating that one-dimensional nanowires Na are produced_0.7MnO₂@Na_0.91MnO₂The @ MnOS composite material has high crystal crystallinity and purity. And the same material is produced both at lower temperature and higher temperature.

The one-dimensional nano-wire Na prepared by the invention_0.7MnO₂@Na_0.91MnO₂@ MnOS complexThe size, the shape, the microstructure and the like of the composite material are analyzed by a Scanning Electron Microscope (SEM).

The one-dimensional nano-wire Na prepared by the invention_0.7MnO₂@Na_0.91MnO₂The @ MnOS composite material adopts a surface scanning method to analyze the distribution state of surface elements and the like.

The one-dimensional nano-wire Na prepared by the invention_0.7MnO₂@Na_0.91MnO₂@MnOS_xThe phase, crystallinity, etc. of the composite material were analyzed by X-ray diffraction (XRD).

The method for calcining manganese oxide at low temperature under the nitrogen condition efficiently and controllably synthesizes the one-dimensional nanowire Na with high crystallinity and uniform appearance_0.7MnO₂@Na_0.91MnO₂@ MnOS composite material. One-dimensional nanowires Na benefiting from ultrasonic synthesis_0.7MnO₂@Na_0.91MnO₂The @ MnOS composite material has high crystallinity and uniform appearance; and the method has the advantages of simple process, low reaction temperature and short time, and is suitable for batch production.