CN110609069A

CN110609069A - Preparation of CuNi/reduced graphene non-enzymatic sulfite electrochemical sensor

Info

Publication number: CN110609069A
Application number: CN201910981103.3A
Authority: CN
Inventors: 罗士平; 朱仕超; 谢爱娟; 刘忠翔; 多晓晓; 袁波; 王飞; 张婉琦
Original assignee: Changzhou University
Current assignee: Changzhou University
Priority date: 2019-10-16
Filing date: 2019-10-16
Publication date: 2019-12-24

Abstract

The invention belongs to the field of electrochemical sensors, and relates to a preparation method of a CuNi/reduced graphene (rGO) non-enzymatic sulfite electrochemical sensor. According to the invention, a CuNi bimetal nano composite material is prepared by a hydrothermal method, Graphene Oxide (GO) is prepared from graphene by an improved Hummer method, the graphene oxide is ultrasonically dispersed and then added into a reaction kettle containing the CuNi bimetal nano composite material to prepare a CuNi/rGO non-enzymatic sulfite electrochemical sensor, and the prepared CuNi/rGO non-enzymatic sulfite electrochemical sensor_1:1/rGO_{1 wt%}The bimetal nano composite material has the characteristics of higher sensitivity, lower detection limit, better stability and reproducibility and better anti-interference capability.

Description

Preparation of CuNi/reduced graphene non-enzymatic sulfite electrochemical sensor

Technical Field

The invention belongs to the field of electrochemical sensors, and relates to a preparation method of a CuNi/reduced graphene (rGO) non-enzymatic sulfite electrochemical sensor.

Background

Over the past few years, there has been a constant thought of how to detect sulphites present in the food industry quickly and efficiently, and in a low cost way. Sulfite is frequently used in the food industry as a preservative for vegetables, fruits and beverages because it is effective in preventing oxidation, inhibiting bacterial growth and preserving sulfite, but it causes harm to the human body once the human body ingests an excessive amount of sulfite. Therefore, it is particularly important to accurately detect the content of sulfite. At present, most sulfite detection methods (such as fluorescence analysis, chemiluminescence, flow injection analysis and the like have the defects of complex sample pretreatment, reagent preparation and the like, and in consideration of the advantages of quick response, high efficiency, convenience, low cost, simplicity in operation and the like, people are greatly concerned about constructing electrochemical sensors for detecting sulfite.

The choice of electrode material will greatly improve the performance of the electrochemical sensor. At present, the performance of the electrochemical sensor is improved mainly by selecting nano materials and porous materials. Because of the large surface area, high charge transfer capability, chemical stability and biocompatibility of these materials, the selectivity and stability of electrochemical sensors can be improved. Conductive polymers, metal oxides, and carbon materials are generally selected as electrode materials because of their characteristics of improving electrochemical sensing performance.

In recent years, graphene attracts great attention due to its unique chemical and physical properties, and its application in electrochemical sensors is particularly extensive. However, since the simple graphene sheet is easily aggregated, the stability and conductivity of the graphene sheet are affected, and thus the application of graphene is limited. Therefore, various functionalized graphene nano materials are continuously synthesized, so that the graphene is protected, and special properties can be endowed to the graphene. Metal nanoparticles are often used to modify graphene with their good electrical conductivity and catalytic properties. Based on the method, the non-enzymatic electrochemical sensor based on the metal nanoparticles/graphene is constructed, and the selectivity and the sensitivity of detection can be greatly improved.

Disclosure of Invention

Based on the reasons, the invention provides a preparation method of a CuNi/rGO non-enzymatic sulfite electrochemical sensor. The preparation method comprises the following specific steps: firstly preparing CuNi bimetal by a hydrothermal method, then preparing Graphene Oxide (GO) by graphite by an improved Hummer method, ultrasonically dispersing the Graphene Oxide (GO) and adding the graphene oxide into a reaction kettle containing CuNi bimetal nano material to prepare the CuNi/rGO non-enzymatic sulfite electrochemical sensor.

(1) Preparing CuNi bimetal nano particles by a hydrothermal method, and adding a certain amount of CuCl₂•2H₂O and NiCl₂•6H₂Dissolving O in 60mL of 2mol/L NaOH solution, stirring for 40min, adding a proper amount of ethylenediamine, and continuing stirring for 5 min; adding a proper amount of sodium hypophosphite (about 0.01mol/L) into the mixed solution, stirring for 30 minutes, transferring the mixture into a high-pressure reaction kettle, reacting for 15 hours at the temperature of 140 ℃, naturally cooling to room temperature, collecting a CuNi product by adopting a centrifugal method, washing with absolute ethyl alcohol and distilled water for three times, and finally drying for 8 hours at the temperature of 60 ℃ to obtain CuNi bimetallic particles;

(2) preparing graphene oxide by using graphite by adopting an improved Hummer method, and adding the graphene oxide into distilled water for ultrasonic dispersion to prepare a reduced graphene dispersion liquid with the concentration of 0.2 g/L;

(3) preparing a CuNi/rGO nano composite material by a hydrothermal method; 30mg of CuNi bimetallic nanoparticles were added to a mixed solution containing 10mL of distilled water and 2mL of anhydrous ethanol. Dispersing a certain amount of 0.2g/L graphene oxide solution into the mixed solution, then carrying out ultrasonic treatment for 1 hour to obtain a uniform suspension, transferring the uniform suspension into a 25 mL-capacity autoclave, reacting for 4 hours at 120 ℃, and naturally cooling to room temperature after the reaction is finished. The CuNi/rGO product was collected by centrifugation and washed three times with absolute ethanol and distilled water. Finally dried at 60 ℃ for 8 hours.

Further, CuCl in the step (1)₂•2H₂O and NiCl₂•6H₂Total mole number of O is 1, its content is 0 ~ 1.0.0 mmol, addition of ethylenediamineThe amount of the catalyst added was 1.5 ~ 5 mL.

Further, the weight percent of rGO in the CuNi/rGO in the step (3) is 0.1 ~ 3 wt%.

The positive progress effects obtained by the invention are as follows: the method has the characteristics of high sensitivity, low detection limit, high stability and reproducibility and high anti-interference capability.

Drawings

The invention will be further explained with reference to the drawings

FIG. 1 is an XRD pattern of CuNi/rGO in example one.

FIG. 2 shows CuNi_1:1/rGO_1wt%And CuNi_3:7/rGO_{1 wt%}CV comparison of composites tested 20 mM sulfite in 0.20M PBS (pH = 7.0).

Detailed Description

The invention will now be further illustrated by reference to specific examples, which are intended to be illustrative of the invention and are not intended to be a further limitation of the invention.

The first embodiment is as follows:

(1) CuNi bimetal nano composite particles are prepared by a hydrothermal method. 0.2407g (0.001 mol/L) of CuCl₂•2H₂O and 0.1705g (0.001 mol/L) NiCl₂•6H₂O was dissolved in 60mL of a 2mol/L NaOH solution, stirred for 40min, 5mL of ethylenediamine was added and dispersed in the mixture, and stirring was continued for 5 minutes. Then, adding a proper amount of sodium hypophosphite (about 0.01mol/L,1.0599g) into the mixed solution, stirring for 30 minutes, then transferring the mixture into a reaction kettle, reacting for 15 hours at 140 ℃, naturally cooling to room temperature, then centrifugally collecting a product, washing with absolute ethyl alcohol and distilled water for three times, and finally drying for 8 hours at 60 ℃ to obtain CuNi bimetallic nanoparticles;

(2) preparing graphene oxide by using graphite by adopting an improved Hummer method, and adding the graphene oxide into distilled water for ultrasonic dispersion to form a brown dispersion to prepare a reduced graphene dispersion liquid with the concentration of 0.2 g/L;

(3) a hydrothermal method is adopted to prepare the CuNi/rGO bimetal nano composite material. Adding 30mg of CuNi bimetallic nanoparticles into the solution containingThere was a mixed solution of 10mL of distilled water and 2mL of absolute ethanol. 1.5mL of 0.2g/L graphene oxide solution was weighed and dispersed into the mixed solution so that the rGO content in the nanocomposite was 1 wt%. Then, carrying out ultrasonic treatment for 1 hour to obtain uniform suspension, transferring the suspension into a 25mL reaction kettle, reacting for 4 hours at 120 ℃, simultaneously reducing graphene oxide by using ethanol as an activating agent in the heating process, naturally cooling to room temperature after the reduction, and collecting CuNi by adopting a centrifugal method_1:1/rGO_1wt%The product was washed three times with absolute ethanol and distilled water and finally dried under vacuum at 40 ℃ for 6 hours.

FIG. 1 is an XRD pattern of CuNi/rGO. The characteristic peaks of Cu and Ni are obvious, and the compounding condition of CuNi and rGO is good.

Comparative example one:

(1) CuNi bimetal nano composite particles are prepared by a hydrothermal method. 0.0512g of CuCl₂•2H₂O and 0.1664g of NiCl₂•6H₂O was dissolved in 30mL of a 2mol/L NaOH solution and stirred for 40min, and then 5mL of ethylenediamine was added and dispersed in the mixture, and stirring was continued for 5 min. Then, an appropriate amount of sodium hypophosphite (about 5mmol) was added to the mixed solution and stirred for 30 minutes, and then the mixture was transferred to a reaction vessel, reacted at 140 ℃ for 15 hours, and then naturally cooled to room temperature. Collecting CuNi by centrifugation_3:7The product was washed three times with absolute ethanol and distilled water. Finally vacuum drying at 40 deg.C for 6 hr;

(3) preparing the CuNi/rGO nano composite material by a hydrothermal method. 30mg of CuNi bimetallic nanoparticles were added to a mixed solution containing 10mL of distilled water and 2mL of anhydrous ethanol. 1.5mL of 0.2g/L graphene oxide solution was weighed and dispersed into the mixed solution so that the rGO content in the nanocomposite was 1 wt%. Then, the suspension was sonicated for 1 hour to obtain a homogeneous suspension, which was transferred to a 25mL reaction vessel and reacted at 120 ℃ for 4 hours while heating with ethanol as an activating agentAnd naturally cooling the original graphene oxide to room temperature after the completion. Collecting CuNi by centrifugation_3:7/rGO_{1 wt%}The product was washed three times with absolute ethanol and distilled water. Finally dried under vacuum at 40 ℃ for 6 hours. FIG. 2 illustrates that CuNi_1:1/rGO_1wt%Compared with CuNi, the bimetal nano composite material_3:7/rGO_{1 wt%}Has high sensitivity.

Claims

1. A CuNi/reduced graphene (rGO) non-enzyme sulfite electrochemical sensor and a preparation method thereof are disclosed, wherein the preparation method comprises the following steps: firstly, CuNi bimetallic nanoparticles are prepared by a hydrothermal method, then Graphene Oxide (GO) is prepared from graphite by an improved Hummer method, the Graphene Oxide (GO) is added into a reaction kettle containing the CuNi bimetallic nanoparticles after being subjected to ultrasonic dispersion, and the CuNi/rGO non-enzymatic sulfite electrochemical sensor is prepared by the following specific steps:

(1) preparing CuNi bimetal nano particles by a hydrothermal method, and adding a certain amount of CuCl₂·2H₂O and NiCl₂·6H₂Dissolving O in 60mL of 2mol/L NaOH solution, stirring for 40min, adding a proper amount of ethylenediamine, and continuing stirring for 5 min; adding a proper amount of sodium hypophosphite (about 0.01mol/L) into the mixed solution, stirring for 30 minutes, transferring the mixture into a high-pressure reaction kettle, reacting for 15 hours at the temperature of 140 ℃, naturally cooling to room temperature, collecting a CuNi product by adopting a centrifugal method, washing with absolute ethyl alcohol and distilled water for three times, and finally drying for 8 hours at the temperature of 60 ℃ to obtain CuNi bimetallic nanoparticles;

(2) preparing graphene oxide by using graphite by adopting an improved Hummer method, and adding the graphene oxide into distilled water for ultrasonic dispersion to prepare a graphene oxide dispersion liquid with the concentration of 0.2 g/L;

(3) preparing a CuNi/rGO nano composite material by a hydrothermal method; adding 30mg of CuNi bimetallic nanoparticles into a mixed solution containing 10mL of distilled water and 2mL of absolute ethyl alcohol, dispersing a certain amount of 0.2g/L graphene oxide solution into the mixed solution, carrying out ultrasonic treatment for 1 hour to obtain a uniform suspension, transferring the uniform suspension into a 25 mL-capacity autoclave, reacting at 120 ℃ for 4 hours, naturally cooling to room temperature, collecting a CuNi/rGO product by a centrifugal method, washing with absolute ethyl alcohol and distilled water for three times, and finally drying at 60 ℃ for 8 hours.

2. The method of claim 1, wherein the CuNi/rGO non-enzymatic sulfite electrochemical sensor is prepared by CuCl in step (1)₂·2H₂O and NiCl₂·6H₂The total mole number of O is 1, the content is 0 ~ 1.0.0 mmol, and the adding quantity of the ethylenediamine is 1.5 ~ 5 mL.

3. The method of claim 1, wherein said ni/rGO non-enzymatic sulfite electrochemical sensor of step (3) comprises 0.1 ~ 3 wt% rGO.