CN111161959B

CN111161959B - ZnS nanowire/Cu7S4Nano particle/reduced graphene oxide composite material and preparation method and application thereof

Info

Publication number: CN111161959B
Application number: CN201811316136.8A
Authority: CN
Inventors: 曹健; 冯博; 李盺
Original assignee: Jilin Normal University
Current assignee: Jilin Normal University
Priority date: 2018-11-07
Filing date: 2018-11-07
Publication date: 2021-09-03
Anticipated expiration: 2038-11-07
Also published as: CN111161959A

Abstract

_The invention discloses a ZnS nanowire/ _Cu7S4 nanoparticle/reduced graphene oxide composite material and a preparation method thereof, belonging to the field of multifunctional composite materials, and is a composite material with both supercapacitor and photocatalytic applications. Although the composite material composed of ZnS and Cu ₇ S ₄ can have both supercapacitor and photocatalytic applications, the material has the problem of low stability. In the present invention, two-dimensional graphene is introduced into the nanocomposite material, and graphene is used as the substrate of the nanocomposite material, which can not only avoid the volume change of ZnS/Cu ₇ S ₄ during charging and discharging, but also provide a large electrode/electrolyte interface to facilitate better ion diffusion. At the same time, ZnS/Cu ₇ S ₄ can also prevent graphene from agglomerating and increase its surface area, enabling the material to have both good electrical properties and photocatalytic performance.

Description

ZnS nanowire/Cu7S4Nano particle/reduced graphene oxide composite material and preparation method and application thereof

Technical Field

The invention belongs to the field of multifunctional composite materials, and particularly relates to a composite material with both a supercapacitor and photocatalytic applications.

Background

Supercapacitors (SC) have attracted considerable attention because of their advantages of higher power density, longer lifetime, lower cost, etc. The properties of which depend mainly on the electrochemical properties of the electrode material. Carbon-based nanomaterials (graphene, carbon nanotubes, etc.) have high specific surface area and high conductivity, but their capacitance mainly results from electrostatic charge adsorption, and thus energy density and power density are low. Transition metal oxides/sulfides or their composites are based on rapid reversible faradaic reactions (redox reactions) for charge storage on the electrode surface and thus have high specific capacitance and energy density. Wherein the transition metal sulfide has lower cost and more abundant oxygen than the metal oxideReduction valence and higher conductivity. Copper sulfide (Cu)_xS, x ═ 1-2) as an important p-type semiconductor, having a band gap of 1.2-2.4eV and a high theoretical capacitance (561mA · h · g)^-1)。Cu₇S₄Is Cu_xThe most stable structure in the S system, and therefore, the S system has good stability. Zinc sulfide (ZnS) is an important wide band gap semiconductor, has a band gap of 3.6eV, has good electrical conductivity, and is widely used as an electrode material of a supercapacitor and a photocatalyst. ZnS and Cu, in contrast to single-component sulfides₇S₄The composite material has higher specific capacity, better electrochemical performance, wider solar energy absorption range and higher photocatalytic efficiency. However, the stability of the sulfides is still low.

Disclosure of Invention

To solve ZnS and Cu₇S₄The invention introduces two-dimensional graphene into the nano composite material, uses the graphene as the substrate of the nano composite material, and can avoid ZnS/Cu₇S₄The volume change during charging and discharging may also provide a large electrode/electrolyte interface to promote better ion diffusion. At the same time, ZnS/Cu₇S₄The graphene can be prevented from being aggregated, the surface area of the graphene can be increased, and the material has good electrical properties and photocatalytic performance.

In addition, the ZnS nanowire/Cu with excellent capacitance and photocatalytic performance is synthesized by a simple one-step hydrothermal method for the first time₇S₄A nanoparticle/reduced graphene oxide nanocomposite. Cu deposition on ZnS nanowire surface by hydrothermal method₇S₄The nano particles form a line-point type nano composite material, the diameter of the ZnS nano line is 8-18 nm, the length of the ZnS nano line is 100-200 nm, and the Cu is₇S₄The diameter of the nanoparticles is 4-8 nm. After the graphene oxide is added in the reaction, the line-point type nano composite material is deposited on the surface of the two-dimensional reduced graphene oxide to form a target product.

Adding 1.6-2.0 mmol of Zn (NO)₃)₂And 1.6 to 2.0mmol of Cu (NO)₃)₂Dispersing in 10mL of deionized water (solution A), dispersing 6.0-6.2 mmol of thiourea in 10mL of ethylenediamine (solution B), dispersing 0.01-0.015 g of graphene oxide in a mixed solution of 10mL of deionized water and 10mL of absolute ethyl alcohol (solution C), ultrasonically dispersing A, B, C solution for 1h, dropwise adding the solution A into the solution C within 30min, continuously stirring for 30min, dropwise adding the solution B into the solution C within 30min, continuously stirring for 30min, transferring the solution B into a 50mL reaction kettle, reacting for 12h at 180 ℃, washing the obtained product with deionized water and absolute ethyl alcohol for 3 times respectively, and drying at 60 ℃ for 6h to obtain the target product.

The preparation method of the graphene oxide comprises the following steps:

1) preparing pre-oxidized graphene: respectively mixing 4.8-5g K₂S₂O₈And 4.8-5g P₂O₅Adding the mixture into a 50mL conical flask, adding 25mL concentrated sulfuric acid, magnetically stirring until the concentrated sulfuric acid is fully dissolved, adding 5.8-6g of graphite powder, putting the graphite powder into a water bath at 80 ℃ for stirring, refluxing for 4.5h, cooling to room temperature, taking out, adding deionized water, pouring into a 1000mL beaker (repeating for many times until no residue exists in the conical flask), filling the 1000mL beaker with the deionized water, pouring the liquid into a 250mL beaker for suction filtration to obtain 4 filter cakes, putting the filter cakes into a culture dish, drying at room temperature, collecting the filter cakes by using the 250mL beaker, and stirring for later use.

2) Preparation of Graphene Oxide (GO): adding 40mL of phosphoric acid, 360mL of sulfuric acid and 2.8-3g of pre-oxidized graphene into a 500mL conical flask, magnetically stirring for 1h, adjusting the temperature of the device to 5 ℃, slowly adding 18-20 g of potassium permanganate within 30 minutes, continuously stirring for 1.5h, adjusting the temperature of the device to 50 ℃, stirring for 12h, stirring for 5 days at room temperature, freezing for later use, slowly pouring 50mL of distilled water into the ice water mixture, releasing heat in the process, dissolving ice, continuously stirring for 30min, pouring 18-20mL of 30% hydrogen peroxide solution, continuously stirring for 2-5h, settling for 12h at room temperature, pumping out supernatant, pouring distilled water, settling for 12h again, and only taking out the supernatant for centrifugal washing. And respectively washing with sulfuric acid, hydrochloric acid and deionized water for multiple times, and freeze-drying to obtain the graphene oxide.

The invention has the beneficial effects that:

1) the invention adopts a one-step hydrothermal method to prepare ZnS nanowires and Cu₇S₄The nano particles and the reduced graphene oxide are compounded together to prepare the nano powder with both electrochemical and photocatalytic applications.

2) The method of the invention separates the graphene sheet layers by ultrasonic treatment, obviously improves ZnS nanowire and Cu₇S₄The binding rate of the nanoparticles on the graphene sheets.

3) The method has the advantages of simple operation, clear steps, environmental protection, economy, convenience, simple operation and the like, and is easy to realize large-scale production.

Drawings

FIG. 1 shows ZnS nanowire/Cu as the target product of the present invention₇S₄A process flow chart of a preparation method of the nano particles/reduced graphene oxide.

FIG. 2 shows ZnS nanowire/Cu as the target product of the present invention₇S₄Nanoparticle/reduced graphene oxide scan.

FIG. 3 shows ZnS nanowire/Cu as the target product of the present invention₇S₄Nanoparticle/reduced graphene oxide X-ray diffraction patterns.

FIG. 4 shows ZnS nanowire/Cu as the target product of the present invention₇S₄Nanoparticle/reduced graphene oxide photocatalytic diagrams.

FIGS. 5-8 show ZnS nanowire/Cu as target products of the present invention₇S₄Nanoparticle/reduced graphene oxide electrochemical property diagrams.

Detailed Description

The raw materials used in this example were as follows:

zinc nitrate (Zn (NO)₃)₂·6H₂O, chemical reagents of national drug group, Ltd.) as an analytical grade;

copper nitrate (Cu (NO)₃)₂·3H₂O, chemical reagents of national drug group, Ltd.) as an analytical grade;

thiourea (H)₂NCSNH₂National pharmaceutical group chemical reagent limited) as analytical grade;

ethylene diamine (H)₂NCH₂CH₂NH₂National pharmaceutical group chemical reagent limited) as analytical grade;

potassium peroxodisulfate (K)₂S₂O₈National pharmaceutical group chemical reagent limited) as analytical grade;

phosphorus pentoxide (P)₂O₅West longa chemical corporation) as analytical grade;

the graphite powder (C, an Aladdin reagent) is analytically pure;

sulfuric acid (H)₂SO₄95% -98%, Beijing chemical plant) is analytically pure;

phosphoric acid (H)₃PO₄Beijing chemical plant) for analytical purification;

potassium permanganate (KMnO)₄Beijing reagent) as analytical grade;

30% hydrogen peroxide (H)₂O₂National pharmaceutical group chemical reagent limited) as analytical grade.

As shown in FIG. 1, the target product ZnS nanowire/Cu₇S₄The preparation method of the nano particle/reduced graphene oxide nano composite material comprises the following steps: 0.611g of Zn (NO)₃)₂·6H₂O and 0.385g Cu (NO)₃)₂·3H₂Dispersing O in 10mL of deionized water (solution A), dispersing 0.469g of thiourea in 10mL of ethylenediamine (solution B), dispersing 0.01g of graphene oxide in a mixed solution of 10mL of deionized water and 10mL of absolute ethyl alcohol (solution C), ultrasonically dispersing A, B, C solution for 1h, dropwise adding the solution A into the solution C within 30min, continuously stirring for 30min, dropwise adding the solution B into the solution C within 30min, continuously stirring for 30min, transferring the solution into a 50mL reaction kettle, reacting for 12h at 180 ℃, washing the obtained product with the deionized water and the absolute ethyl alcohol for 3 times respectively, and drying at 60 ℃ for 6h to obtain the target product.

Performing scanning electron microscope characterization on the target product, as shown in fig. 2, the bottommost wrinkled material is reduced graphene oxide, and ZnS nanowire/Cu is arranged on the material₇S₄Nanoparticles. Cu₇S₄The nano particles are coated on the surface of the ZnS nano wire to ensure that the surface of the nano wire is roughIs rough, thereby increasing the active sites on the surface. At the same time, ZnS nanowire/Cu₇S₄The nanoparticles can avoid the agglomeration of graphene.

FIG. 3 shows ZnS nanowire/Cu as the target product of the present invention₇S₄X-ray diffraction pattern of nanoparticle/reduced graphene oxide nanocomposite. As can be seen from the figure, the target product contains ZnS nanowires and Cu at the same time₇S₄Diffraction peaks of the nanoparticles, and thus the target product, were successfully synthesized. Due to the fact that the amount of the graphene oxide is small, diffraction peaks related to graphene in a target product are not obvious.

FIG. 4 shows ZnS nanowire/Cu as the target product of the present invention₇S₄The photocatalytic degradation diagram of the nanoparticle/reduced graphene oxide nanocomposite shows that the catalytic effect is good no matter the catalytic degradation is carried out under the irradiation of visible light or ultraviolet light. Under uv light, MB can be degraded within 1 hour, and under visible light, MB can be degraded within 2 hours.

FIG. 5 shows ZnS nanowire/Cu as the target product of the present invention₇S₄The electrical properties of the nanoparticle/reduced graphene oxide nanocomposite can be seen from the figure, the target product has a high capacitance value of 1114F/g, after 2000 times of cyclic use, the capacitance retention rate is 91.3%, and the charge transfer resistance is only 0.011 omega.

Claims

1. a ZnS nanowire/ _Cu7S4 nanoparticle/reduced graphene oxide composite material, is characterized in that, _ZnS nanowire surface deposition _Cu7S4 nanoparticle forms line _- dot type nanocomposite structure, and this nanocomposite structure ZnS nanowires/Cu ₇ S ₄ nanoparticles/reduced graphene oxide composites were deposited on the surface of two-dimensional reduced graphene oxide. The diameter of the ZnS nanowires was 8-18 nm and the length was 100-200 nm; Cu ₇ S ₄ The diameter of the nanoparticles is 4–8 nm.

2. a preparation method of ZnS nanowire/ _Cu7S4 nanoparticle/reduced graphene oxide composite material as claimed in claim ₁ , concrete steps are as follows:

Disperse 1.6~2.0 mmol Zn(NO ₃ ) ₂ and 1.6~2.0 mmol Cu(NO ₃ ) ₂ in 10 mL deionized water to obtain solution A, and disperse 6.0~6.2 mmol thiourea in 10 mL ethylenediamine to obtain solution B. Disperse 0.01~0.015 g graphene oxide in a mixed solution of 10 mL deionized water and 10 mL absolute ethanol to obtain solution C, ultrasonically disperse solution A, solution B, and solution C for 1 h, and place solution A at 30 Add dropwise to solution C within 30 min, continue to stir for 30 min, add solution B dropwise to solution C within 30 min, continue to stir for 30 min, transfer it to a 50 mL reaction kettle, and react at 180 °C for 12 h, the product obtained by the reaction was washed with deionized water and absolute ethanol respectively and dried to obtain the target product.

3. the preparation method of ZnS nanowire/Cu ₇ S ₄ nanoparticle/reduced graphene oxide composite material according to claim 2, is characterized in that, the preparation step of described graphene oxide is as follows:

1) Preparation of pre-oxidized graphene: 4.8~5 g K ₂ S ₂ O ₈ and 4.8~5 g P ₂ O ₅ were respectively added to a 50 mL conical flask, 25 mL concentrated sulfuric acid was added, and magnetic stirring was performed until fully dissolved. Add 5.8~6 g graphite powder, put it into a water bath at 80 °C and stir, reflux for 4.5 h, cool it to room temperature, take it out, add deionized water, then pour it into a 1000 mL beaker, repeat several times, until the conical flask There is no residue in it, and the 1000 mL beaker is filled with deionized water, and the liquid is poured into a 250 mL beaker for suction filtration to obtain 4 filter cakes, which are placed in a petri dish, dried at room temperature, and 250 mL Collect in a beaker, crush it for use;

2) Preparation of graphene oxide: 40 mL of phosphoric acid, 360 mL of sulfuric acid and 2.8–3 g of pre-oxidized graphene oxide were added to a 500 mL conical flask, magnetically stirred for 1 h, and the temperature of the device was adjusted to 5 °C for 30 min. Slowly add 18-20 g of potassium permanganate into it, continue to stir for 1.5 h, then adjust the temperature of the device to 50 °C and stir for 12 h, stir at room temperature for 5 days, freeze for use, slowly pour 50 mL of distilled water into the ice-water mixture, This process exothermic, after the ice is dissolved, continue stirring for 30 min, pour 18~20mL of 30wt% hydrogen peroxide solution, the solution turns bright yellow at this time, continue to stir for 2-5 h, settle at room temperature for 12 h, put the upper layer The clear liquid was pumped out, poured into distilled water, and settled again for 12 h. At this time, only the upper layer solution was taken for centrifugal washing; washed with sulfuric acid, hydrochloric acid and deionized water for several times, respectively, and freeze-dried to obtain graphene oxide.

_4. A use of the ZnS nanowire/ _Cu7S4 nanoparticle/reduced graphene oxide composite material as claimed in claim 1 for supercapacitors and photocatalysis.