CN114636740A - Working electrode for alcohol electrochemical sensor and preparation method thereof - Google Patents

Working electrode for alcohol electrochemical sensor and preparation method thereof Download PDF

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CN114636740A
CN114636740A CN202210179935.5A CN202210179935A CN114636740A CN 114636740 A CN114636740 A CN 114636740A CN 202210179935 A CN202210179935 A CN 202210179935A CN 114636740 A CN114636740 A CN 114636740A
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徐迎庆
杨佳伟
路奇
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Tsinghua University
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Abstract

The invention relates to an electrochemical sensor, in particular to a working electrode for an alcohol electrochemical sensor and a preparation method thereof. The working electrode for the alcohol electrochemical sensor is prepared by performing electrostatic spinning on a heterogeneous phase Au @ Pd core-shell nanorod and conductive carbon paper; the heterogeneous phase Au @ Pd core-shell nanorod comprises a core and a shell; the core is heterogeneous phase ABA type Au, and the stacking sequence is ABA; the shell is heterogeneous phase ABA type Pd, and the stacking sequence is ABA; a represents face centered cubic and B represents hexagonal close packing. The invention is used for the working electrode of the alcohol electrochemical sensor, shows excellent electrocatalytic ethanol oxidation performance, and also has good durability and very high structural stability.

Description

Working electrode for alcohol electrochemical sensor and preparation method thereof
Technical Field
The invention relates to an electrochemical sensor, in particular to a working electrode for an alcohol electrochemical sensor and a preparation method thereof.
Background
The crystalline phase heterostructure of the noble metal nano material has wide application prospect in the fields of electrochemical sensing, plasma, catalysis and the like. However, the synthesis of a specific crystalline phase of noble metals remains a huge challenge, which makes it difficult to build heterogeneous noble metal nanostructures.
Palladium-based nanostructured particles have been recognized as one of the most promising anode catalysts for direct ethanol fuel cells (DAFCs) under alkaline conditions, and the preparation of high-performance Pd-based anode catalysts is of great significance not only for the practical application of DAFCs, but also for the development of working electrodes of alcohol electrochemical sensors.
Disclosure of Invention
The present invention is directed to solving at least one of the above problems.
The inventor synthesizes heterogeneous ABA type Au nanorods (A: face-centered cubic (fcc); B: hexagonal close-packed (2H) with the packing order of 'ABA') with precise structure by one-pot wet chemistry method under mild conditions. Meanwhile, the Au @ Pd bimetallic nanorod with a clearly defined heterogeneous phase nano core-shell structure is synthesized by using the Au nanorod as a core through a low-temperature photoreduction epitaxial growth method, and is used as a sensing material, a working electrode is prepared through an electrostatic spinning technology, and electrochemical sensing tests are carried out on ethanol, methanol, ethylene glycol and glycerol under an alkaline condition, so that the performance of the Au @ Pd bimetallic nanorod is superior to that of a commercial Pd/C material. The method lays a practical foundation for preparing the alcohol electrochemical sensor.
The invention firstly provides a heterogeneous phase Au @ Pd core-shell nanorod, which comprises a core and a shell; the core is heterogeneous phase ABA type Au (gold), and the stacking sequence is ABA; the shell is heterogeneous phase ABA type Pd (palladium), and the stacking sequence is ABA; a represents face centered cubic (fcc), and B represents hexagonal close packing (2H).
According to the embodiment of the invention, the deposition amount and the deposition position of the shell Pd of the heterogeneous phase Au @ Pd core-shell nanorod can be adjusted by controlling the reduction condition.
According to the embodiment of the invention, in the preparation process of the heterogeneous phase Au @ Pd core-shell nanorod, the heterogeneous phase ABA type Pd is preferentially deposited at the grain boundary of the heterogeneous phase ABA type Au, and the reduced Pd covers the whole heterogeneous phase Au core with the increase of the concentration of Pd precursor salt and the enhancement of the reduction condition, so that a complete core-shell structure is formed.
The invention also provides a preparation method of the heterogeneous phase Au @ Pd core-shell nanorod, which comprises the step of preparing the heterogeneous phase ABA type Au nanorod by using a low-temperature photoreduction epitaxial growth method by using the heterogeneous phase ABA type Au nanorod as a raw material, namely depositing Pd on the heterogeneous phase ABA type Au nanorod by using a low-temperature photochemical reduction method.
According to the embodiment of the invention, the heterogeneous phase ABA type Au nanorod can be prepared by adopting the existing method.
According to the embodiment of the invention, the preparation method of the heterogeneous phase ABA type Au nanorod comprises the following steps: n-dodecylamine (0.1g) and oleylamine (1mL) were first dissolved in a glass vial to form a homogeneous solution, denoted as solution A; then adding a certain mass of HAuCl4Into a glass bottle containing solution A, and then oxygen was bubbled into the solution. After sealing the glass vial, the mixture was sonicated. The resulting solution was then heated overnight in a 65 ℃ oil bath for 18 hours to effect reaction. And after the reaction is finished, washing the colloid sample by using an organic solvent to obtain the heterogeneous phase ABA type Au nanorod. The method comprises the following steps: a certain amount of a mixture of cyclohexane and ethanol (v/v-5/1) was added to the resulting solution, and the colloidal product was collected by centrifugation after sonication. After repeating the above washing process several times, the thoroughly washed colloidal sample was redispersed in cyclohexane for further use.
According to the embodiment of the invention, the preparation method of the heterogeneous phase Au @ Pd core-shell nanorod comprises the following steps:
1) providing heterogeneous phase ABA type Au nanorods (same as above);
2) preparing heterogeneous phase Au @ Pd core-shell nanorod:
mixing the colloidal solution of the heterogeneous phase ABA type Au nanorod, a palladium acetylacetonate solution and a potassium halide solution to prepare a mixed solution; cooling and solidifying; reducing under the irradiation of light.
In some examples, the colloidal solution of heterogeneous ABA type Au nanorods has a concentration of 10-50 mM.
In some examples, the palladium acetylacetonate solution has a concentration of 10 to 50 mM.
In some examples, the potassium halide solution is at a concentration of 0.1 to 1 mM.
In some examples, the molar ratio of Au to Pd in the mixed solution of the colloidal solution of the heterogeneous ABA type Au nanorods, the palladium acetylacetonate solution and the potassium halide solution is in the range of 5:1 to 1: 1; and/or the molar ratio of potassium halide to Pd is in the range of 10:1 to 1: 1. The research shows that the Pd can be directionally deposited on the heterogeneous phase ABA type Au nanorod by adjusting the concentration of the Pd precursor salt in the mixed solution or further adjusting the concentration of the potassium halide guiding agent.
In some examples, the potassium halide may be KI or KBr. The potassium halide acts primarily as a directing agent with the aim of directing the deposition of Pd.
In some examples, after the colloidal solution of the heterogeneous phase ABA type Au nanorods, the palladium acetylacetonate solution and the potassium halide solution are mixed, the mixture is sufficiently stirred at room temperature, for example, for 12 to 18 hours, to prepare a mixed solution.
In some examples, the mixture is placed in a cold trap containing liquid nitrogen and rapidly cooled to solidify.
In some examples, the power of the light irradiation is between 100 and 1000W. The Xe lamp, high pressure mercury lamp, or tungsten lamp may be used. Research shows that if the irradiation power is lower than 100W, the reduction speed of Pd is slower; above 1000W, Pd alone may nucleate and the particle size may become larger.
In some examples, the reduction temperature under light irradiation ranges from-20 ℃ to room temperature to control the reduction rate of Pd.
In some examples, a step of washing with cyclohexane after reduction under light irradiation is further included. The thoroughly washed sample can be re-dissolved in cyclohexane and stored for use.
In some examples, a method of preparing a heterogeneous phase Au @ Pd core-shell nanorod comprises: mixing a colloidal solution of a heterogeneous phase ABA type Au nanorod, a palladium acetylacetonate solution and a potassium halide solution to prepare a mixed solution; then placing the mixture in a cold trap filled with liquid nitrogen, and quickly cooling and solidifying the mixture; the solidified frozen substance is put under the irradiation of light for photoreduction (at-20 ℃ to room temperature) until the ice blocks are completely melted (stirring is continued for 1 hour); after centrifugation, the mixture was washed with cyclohexane.
The inventor researches and discovers that Pd atoms can be uniformly deposited on the surface of the heterogeneous Au nanorod by a low-temperature photochemical reduction epitaxial growth method. By increasing or decreasing the irradiation power of the Xe lamp and controlling the concentration of the Pd precursor salt, the Pd/Au atomic ratio in the heterogeneous phase Au @ Pd core-shell nanorod and the dispersion state of Pd on the Au surface can be adjusted. Within the above condition range, the heterogeneous phase Au @ Pd core-shell nanorod can remarkably improve the activity of catalyzing alcohol oxidation, and the durability and the structural stability of the nanorod can be further improved.
According to the embodiment of the invention, in the preparation method of the heterogeneous phase Au @ Pd core-shell nanorod, the concentration of Pd precursor salt is reduced, the reduction strength is modulated, Pd reduction can be preferentially deposited at the grain boundary of the heterogeneous phase under the conditions of lower Pd precursor salt concentration and milder reduction, and the reduced Pd can cover the whole heterogeneous phase Au core with the increase of the Pd precursor salt concentration and the enhancement of the reduction conditions, so that a complete core-shell structure is formed.
The invention also provides the heterogeneous phase Au @ Pd core-shell nanorod prepared by the method.
The invention also provides a working electrode for the alcohol electrochemical sensor, which comprises conductive carbon paper and the heterogeneous phase Au @ Pd core-shell nanorod loaded on the conductive carbon paper.
In the working electrode, the heterogeneous phase Au @ Pd core-shell nanorod is used as a catalyst, and the conductive carbon paper is used as a working electrode substrate and a nanorod carrier.
According to the embodiment of the invention, the heterogeneous phase Au @ Pd core-shell nanorod is loaded on conductive carbon paper by an electrostatic spinning method to prepare the conductive carbon paper.
According to the embodiment of the invention, the heterogeneous phase Au @ Pd core-shell structure nanorod used in the working electrode of the alcohol electrochemical sensor has adjustable weight on the working electrode (conductive carbon paper) per unit area, for example, the mass range of an active metal component Pd is 0.1-2 mu g mm-2. It was found that in this ratio range, the operating voltage was set to 0.74V (vs. rhe) in the alkaline electrolyte solution, and the response current of this working electrode to ethanol of 1000ppm was 4.4 times, 12.6 times and 11.6 times that of the fcc-Pd working electrode, the 2H-Pd working electrode and the commercial Pd/C working electrode.
According to the embodiment of the invention, the working electrode for the alcohol electrochemical sensor further comprises a conductive adhesive, such as a nature solution, an ionic gel, a polymer ionic liquid and the like. The conductive adhesive has the main function of assisting in loading the heterogeneous phase Au @ Pd core-shell nanorod on conductive carbon paper. In addition, the conductive adhesive has a certain conductive function and is beneficial to the adsorption of the conductive carbon paper on the nano-rods.
In some embodiments, the Nafion solution is available from dow chemical, usa, model D2021.
In some embodiments, the conductive carbon paper is available from Toray corporation of Japan, model TGP-H-90).
The invention also provides a preparation method of the working electrode for the alcohol electrochemical sensor, which comprises the following steps: providing a heterogeneous phase Au @ Pd core-shell nanorod (same as above); mixing the heterogeneous phase Au @ Pd core-shell nanorod, conductive adhesive (such as Nafion solution) and isopropanol to prepare a mixture; and (4) carrying out electrostatic spinning to prepare the working electrode of the electrochemical sensor.
According to the embodiment of the invention, in the preparation method, the concentration range of the heterogeneous phase Au @ Pd core-shell nanorod in an isopropanol aqueous solution with the volume ratio of (1:4) is 2-40mg/mL, and the volume ratio of a Nation solution to the isopropanol aqueous solution in which the heterogeneous phase Au @ Pd core-shell nanorod is dissolved is 0.5: 1-3: 1. The voltage range of the electrostatic spinning machine is 10-20kV, and the advancing speed of an injector of the electrostatic spinning machine is 0.05mm/min to 0.5 mm/min.
In some embodiments, the heterogeneous phase Au @ Pd core-shell nanorods, Nafion solution, and isopropanol were mixed under sonication conditions to make a mixture.
The invention also discloses a working electrode for the alcohol electrochemical sensor prepared by the method.
The invention also comprises the application of the working electrode for the alcohol electrochemical sensor in catalyzing alcohol oxidation.
The invention also provides an alcohol fuel cell, which comprises the working electrode for the alcohol electrochemical sensor.
In some embodiments, the alcohols include methanol, ethanol, ethylene glycol, and glycerol.
The electrochemical response current intensity of the electrochemical response electrode for the alcohol is 4.4 times, 12.6 times and 11.6 times of that of the fcc-Pd working electrode, the 2H-Pd working electrode and the commercial Pd/C working electrode respectively. In addition, the electrode can also be used as a working electrode of a methanol, glycol and glycerol electrochemical sensor. The invention is used for the working electrode of the alcohol electrochemical sensor, and also has good durability and very high structural stability. The preparation method of the invention opens up a way for developing high-performance alcohol electrochemical sensors for future practical application.
Drawings
FIG. 1: the embodiment of the invention has the synthesis and structural characterization of fcc-2H-fcc heterogeneous phase Au @ Pd core-shell nanorod.
FIG. 2: the response curve of each electrochemical sensor working electrode to different concentrations of ethanol at 0.74V (vs. rhe).
FIG. 3: the response curve of each electrochemical sensor working electrode to different concentrations of methanol at 0.68V (vs. rhe).
FIG. 4 is a schematic view of: the response curve of each electrochemical sensor working electrode to different concentrations of ethylene glycol at 0.72V (vs. rhe).
FIG. 5: the response curve of each electrochemical sensor working electrode to different concentrations of glycerol at 0.69V (vs. rhe).
Detailed Description
The following examples are intended to illustrate the invention, but are not intended to limit the scope of the invention. The examples do not show the specific techniques or conditions, according to the technical or conditions described in the literature in the field, or according to the product specifications. The reagents or instruments used are conventional products available from regular distributors, not indicated by the manufacturer.
Example 1
Synthesizing a heterogeneous phase ABA type Au nanorod by a one-pot method: first 0.1g of n-dodecylamine and 1mL of oleylamine were dissolved in a glass bottle to form a homogeneous solution, denoted as solution A. Then 3mg of HAuCl4Into a glass bottle containing solution A, and then oxygen was bubbled into the solution. After sealing the glass vial, the mixture was sonicated. The resulting solution was then heated overnight in a 65 ℃ oil bath for 18 hours to effect reaction. And after the reaction is finished, washing the colloid sample by using an organic solvent to obtain the heterogeneous phase ABA type Au nanorod. The method comprises the following steps: a certain amount of a mixture of cyclohexane and ethanol (v/v-5/1) was added to the resulting solution, and the colloidal product was collected by centrifugation after sonication. After repeating the above washing process several times, the thoroughly washed colloidal sample was redispersed in cyclohexane for further use.
Example 2
Synthesis of heterogeneous phase Au @ Pd core-shell nanorod: the Au @ Pd nanorod with the heterogeneous core-shell structure is prepared by adopting a low-temperature photoreduction epitaxial growth method. The heterogeneous Au colloidal solution (concentration: 10mM) obtained in example 1 and a palladium acetylacetonate solution (Pd molar concentration: 10mM) were mixed in a round-bottomed flask with a KI solution (concentration: 0.1mM), and the mixture was stirred at room temperature for 12 hours to prepare a mixture (wherein the molar ratio of Au to Pd was 1:1 and the molar ratio of KI to Pd was 4: 1). The round-bottomed flask was then placed in a cold trap containing liquid nitrogen and the solution was allowed to solidify by rapid cooling. The flask containing the solidified ice was placed under a 300W Xe lamp at room temperature for photoreduction until the ice was completely melted and stirring was continued for 1 hour. And centrifuging, washing with cyclohexane, repeating the process for 5 times, dissolving the completely washed sample in cyclohexane, and storing for later use to obtain the heterogeneous Au @ Pd core-shell nanorod.
The synthesis process and the structure of the heterogeneous Au @ Pd core-shell nanorod in the embodiment are schematically shown in FIG. 1.
In FIG. 1, a is a schematic diagram of the synthesis of a hetero-phase Au @ Pd nanorod by growing Pd on the hetero-phase Au nanorod in an epitaxial distribution manner; b typical spherical aberration corrected HAADF-STEM plots of Au @ Pd nanorods of different ratios (Pd/Au atomic ratio from left to right, 0, 0.2, 0.5), with 2H/fcc phase boundaries marked with white dashed lines; c typical EDS element map of Au @ Pd nanorods of different ratios (Pd/Au atomic ratio from left to right, 0, 0.2, 0.5).
As shown in fig. 1, the heterogeneous phase Au @ Pd core-shell nanorod comprises a core and a shell; the core is heterogeneous phase ABA type Au (gold), and the stacking sequence is ABA; the shell is heterogeneous phase ABA type Pd (palladium), and the stacking sequence is ABA; a represents face centered cubic (fcc), and B represents hexagonal close packing (2H). By controlling the reduction condition, the deposition amount and the deposition position of the shell Pd of the heterogeneous phase Au @ Pd core-shell nanorod can be adjusted. In the preparation process of the heterogeneous phase Au @ Pd core-shell nanorod, the heterogeneous phase ABA type Pd is preferentially deposited at the grain boundary of the heterogeneous phase ABA type Au, and the reduced Pd covers the whole heterogeneous phase Au core with the increase of the concentration of Pd precursor salt and the enhancement of the reduction condition, so that a complete core-shell structure is formed.
From the pictures characterized by the high-resolution transmission electron microscope and the energy spectrum analysis of the sample (b and c in fig. 1), the inventors have succeeded in preparing heterogeneous Au nanorods whose structural phase is arranged in the order face-centered cubic-hexagonal close-packed-face-centered cubic. The Pd precursor salt successfully grows on the surface of the Au nano rod after low-temperature photochemical reduction, a special core-shell structure is formed, and the initial structure of the heterogeneous Au nano rod is not damaged.
Example 3
Preparing a working electrode of the electrochemical sensor:
100mg heterogeneous phase Au @ Pd core-shell nanorod (Pd mass fraction is 50 wt%, example 2) sample, 20mL isopropanol water solution with volume ratio (1:4) is added, 20mL Nation solution is added, and ultrasonic mixing is carried out for 3 hours. Transferred to the needle syringe of the electrospinning machine.
The high voltage electrical connector is connected to the syringe needle. The high voltage is 15kV, and the conductive carbon paper is wrapped on the cylindrical receiver. And (3) turning on a power supply of the spinning machine, and adjusting the proper propelling speed of the injector and the distance between the injector and the receiving plate to ensure that the liquid in the injector is uniformly sprayed on the conductive carbon paper. After the spraying is finished, the carbon paper is taken down, and the carbon paper is cut by a ceramic knife, wherein the typical size of the carbon paper is 2cm multiplied by 2cm, and the carbon paper is used as a working electrode of the electrochemical sensor. The content of an active metal component Pd on the conductive carbon paper is 1 mu g mm-2。
Comparative example 1
The preparation of face-centered cubic Au nanoparticles (fcc-Au) by a seed growth method comprises the steps of firstly preparing Au seeds. In general, a certain amount of HAuCl4(10mM，H2O) was mixed with an amount of CTAB (100mM) to form a homogeneous solution, called solution B. Then, under vigorous stirring, a quantity of freshly prepared ice-cold NaBH is added4(10mM，H2O) is added to the solution B. The resulting seed solution was stirred continuously at room temperature for 20 minutes until use. These Au species were then used to grow Au nanorods as follows: a certain amount of HAuCl4(10mM，H2O) with an amount of CTAB (100mM, H)2O) to form a homogeneous solution, referred to as solution C. Then a certain amount of hydrochloric acid (1M, H)2O), a certain amount of L-ascorbic acid (100mM, H)2O) and a quantity of freshly prepared Au seed solution were added successively to solution C and the resulting growth solution was held at 30 ℃ for 2 hours. After the reaction was completed, the reaction mixture was centrifuged for 5 minutes, and a colloidal sample was collected. After thorough washing with water, the sample was redispersed in water.
Comparative example 2
Synthesis of hexagonal close-packed Au nanoparticles (2H-Au): a certain amount of HAuCl is continuously added into a glass bottle4An amount of oleylamine and an amount of hexane. The vial was then sealed and gently shaken after sealing to allow HAuCl4Dissolved in a mixture of n-hexane and oleylamine. The growth solution produced in the glass bottle was heated at 50 ℃ for 16 hours, and after completion of the reaction, it was centrifuged for 5 minutes, and a colloidal sample was collected. The sample was thoroughly washed with n-hexane and then redispersed in cyclohexane.
Comparative example 3
Synthesis of face-centered cubic Pd nanoparticles (fcc-Pd): similar to the synthesis method of the face-centered cubic Au nanoparticles of comparative example 1, the precursor salt was changed to palladium acetylacetonate.
Comparative example 4
Synthesis of hexagonal close-packed Pd nanoparticles (2H-Pd): and (3) reprocessing the Pd nanoparticles prepared in the step (4) by adopting a phase transfer method: under magnetic stirring, an amount of face centered cubic Pd nanoparticles and an amount of oleylamine were mixed, added to a 50mL Schlenk tube, stirred at room temperature for a while, and after evacuating the tube for 10 minutes, then sealed to maintain a high vacuum. Subsequently, the Schlenk tube was placed in an oil bath at 180 ℃ for 24 hours, and then naturally cooled to room temperature. Adding a certain amount of ethanol into the solution after reaction, centrifuging for 10 minutes, and collecting the product. After thorough washing, the sample was redispersed in toluene.
Comparative example 5
According to the method of example 3, heterogeneous phase Au @ Pd core-shell nanorods are respectively replaced by face-centered cubic Au nanorods of comparative example 1, hexagonal close-packed Au nanoparticles of comparative example 2, face-centered cubic Pd nanoparticles of comparative example 3, and hexagonal close-packed Pd nanoparticles of comparative example 4, and corresponding electrodes are prepared, and are respectively numbered as working electrodes of comparative examples 1-4.
The mass of the conductive carbon paper and all the active metal component Pd sprayed on the conductive carbon paper was the same as in example 3.
Experiment 1
The following commercial Pd/C was purchased from Mingchuang, Germany with a Pd mass fraction of 10 wt%.
Electrochemical sensing characteristics of the working electrodes of example 3 and comparative examples 1-4 to various alcohols were tested in alkaline electrolytes based on Alcohol Oxidation Reactions (AORs).
The working electrode test was carried out under alkaline electrolyte conditions (1M NaOH solution), the reference electrode was a Reversible Hydrogen Electrode (RHE), the counter electrode was Pt wire, and the sweep rate of the cyclic voltammogram was 50mV S-1。
The EOR (ethanol electro-oxidation) performance was compared under the same experimental conditions.
First, a three-electrode experimental test system was assembled. Typically, aThe 2cm × 2cm square conductive carbon paper loaded with noble metal catalyst prepared in example 3 and comparative examples 1 to 4 were used as working electrodes, and were fixed by clips and connected to the working electrode interface of the electrochemical workstation. The counter electrode is Pt wire, the reference electrode is reversible hydrogen electrode, and the counter electrode and the reference electrode are respectively connected with the corresponding interfaces of the electrochemical workstation. The three electrodes were placed in a 500mL beaker containing alkaline electrolyte, 1M NaOH. The beaker for electrochemical test is placed in a constant temperature water bath at 25 ℃, and the test is started after the power supply of the instrument is switched on. By using cyclic voltammetry (scan voltage range is 0.1V to 1.5V, scan speed is 50mV S)-1) In N containing 1.0M ethanol and 1.0M NaOH2The EOR performance of the working electrodes is tested in a saturated aqueous solution, each working electrode provides the maximum EOR current density in the potential range of 0.6-0.9V (and RHE, reversible hydrogen electrode), but the original heterogeneous Au nanorod has no obvious catalytic action on electrochemical EOR. The electrochemical sensing response current of each working electrode to different concentrations of ethanol in alkaline solution at 0.74V (vs. rhe) working voltage is shown in fig. 2.
The heterogeneous Au @ Pd nanorod working electrode (example 3) showed 4.4 times, 12.6 times and 11.6 times higher intensities of electrochemical response current to 1M ethanol than the fcc-Pd working electrode (comparative example 3), the 2H-Pd working electrode (comparative example 4) and the commercial Pd/C working electrode, respectively.
In addition, working electrode stability is another important measure of electrochemical sensor performance. For heterogeneous Au @ Pd working electrode (example 3) at 0.74V (vs. RHE) working voltage, N of 1.0M ethanol and 1.0M NaOH2Under the experimental conditions of saturated aqueous solution, a cyclic pulse experiment was performed. After 500 times, the corresponding current of the heterogeneous phase Au @ Pd working electrode is not obviously changed, and the appearance and heterogeneous phase of the heterogeneous phase Au @ Pd nanorod are not changed. These results reveal that the heterogeneous phase bimetallic nanorod working electrode synthesized by the inventors has good durability and very high structural stability. In addition, the heterogeneous phase bimetal nanorod working electrode still shows better sensing performance than a commercial Pd/C working electrode in a sensing test based on Methanol (MOR), Ethylene Glycol (EGOR) and Glycerol (GOR) electrooxidation reaction, such asFig. 3, 4 and 5.
Based on the results, the heterogeneous phase bimetal nanorod working electrode can be used for preparing alcohol electrochemical sensors and is superior to a commercial Pd/C material.
Although the invention has been described in detail with respect to the general description and the specific embodiments thereof, it will be apparent to those skilled in the art that modifications and improvements can be made based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.

Claims (10)

1. A heterogeneous phase Au @ Pd core-shell nanorod is characterized by comprising a core and a shell; the core is heterogeneous phase ABA type Au, and the stacking sequence is ABA; the shell is heterogeneous phase ABA type Pd, and the stacking sequence is ABA; wherein A represents face centered cubic (fcc), and B represents hexagonal close packing (2H).
2. The heterogeneous phase Au @ Pd core-shell nanorod according to claim 1, wherein the deposition amount and the deposition position of the shell Pd of the heterogeneous phase Au @ Pd core-shell nanorod are adjustable by controlling the reduction conditions; and/or the presence of a gas in the atmosphere,
in the preparation process of the heterogeneous phase Au @ Pd core-shell nanorod, the heterogeneous phase ABA type Pd is preferentially deposited at the grain boundary of the heterogeneous phase ABA type Au, and the reduced Pd covers the whole heterogeneous phase Au core with the increase of the concentration of Pd precursor salt and the enhancement of the reduction condition, so that a complete core-shell structure is formed.
3. The preparation method of the heterogeneous phase Au @ Pd core-shell nanorod as claimed in claim 1 or 2, characterized in that the heterogeneous phase ABA type Au nanorod is used as a raw material, and Pd is deposited on the heterogeneous phase ABA type Au nanorod by using a low-temperature photochemical reduction method.
4. The preparation method of the heterogeneous phase Au @ Pd core-shell nanorod as claimed in claim 1 or 2, is characterized by comprising the following steps:
1) providing a heterogeneous phase ABA type Au nanorod;
2) preparing heterogeneous phase Au @ Pd core-shell nanorod: mixing the colloidal solution of the heterogeneous phase ABA type Au nanorod, a palladium acetylacetonate solution and a potassium halide solution to prepare a mixed solution; cooling and solidifying; reducing under the irradiation of light.
5. The method according to claim 4, wherein the mixed solution contains Au and Pd at a molar ratio of 5:1 to 1: 1; and/or the presence of a gas in the atmosphere,
in the mixed solution, the molar ratio of the potassium halide to the Pd is in the range of 10:1 to 1: 1; and/or the presence of a gas in the gas,
the potassium halide is KI or KBr; and/or the presence of a gas in the gas,
the power of the light irradiation is between 100 and 1000W; and/or the presence of a gas in the gas,
the temperature range of reduction under light irradiation is-20 ℃ to room temperature.
6. The preparation method according to claim 4 or 5, comprising mixing a colloidal solution of heterogeneous phase ABA type Au nanorods, a palladium acetylacetonate solution and a potassium halide solution to prepare a mixed solution; then placing the mixture in a cold trap filled with liquid nitrogen, and quickly cooling and solidifying the mixture; placing the solidified frozen substance under light irradiation for photoreduction until the ice blocks are completely melted; after centrifugation, the mixture was washed with cyclohexane.
7. A working electrode for an alcohol electrochemical sensor is characterized by comprising conductive carbon paper and the heterogeneous phase Au @ Pd core-shell nanorod loaded on the conductive carbon paper, wherein the heterogeneous phase Au @ Pd core-shell nanorod is loaded on the conductive carbon paper;
optionally, the heterogeneous phase Au @ Pd core-shell nanorod is loaded on conductive carbon paper by an electrostatic spinning method to prepare the conductive carbon paper; and/or the presence of a gas in the gas,
optionally, the mass range of an active metal component Pd in the heterogeneous phase Au @ Pd core-shell structure nanorod in the working electrode is 0.1-2 μ g mm-2。
8. The method of claim 7, comprising: providing a heterogeneous phase Au @ Pd core-shell nanorod; mixing the heterogeneous phase Au @ Pd core-shell nanorod, conductive adhesive and isopropanol to prepare a mixture; carrying out electrostatic spinning to prepare a working electrode of the electrochemical sensor;
optionally, the conductive adhesive is a Nafion solution; and/or the presence of a gas in the gas,
optionally, the heterogeneous phase Au @ Pd core-shell nanorod has a concentration range of 2-40mg/mL in an isopropanol aqueous solution with a volume ratio of (1: 4); and/or the presence of a gas in the atmosphere,
optionally, the volume ratio of the Nation solution to the isopropanol aqueous solution in which the heterogeneous phase Au @ Pd core-shell nanorod is dissolved is in the range of 0.5:1 to 3: 1; and/or the presence of a gas in the gas,
optionally, the voltage range of the electrospinning machine is 10-20kV, and the injector propulsion speed of the electrospinning machine is 0.05mm/min to 0.5 mm/min.
9. The use of the working electrode for alcohol electrochemical sensor according to claim 7 or the working electrode for alcohol electrochemical sensor prepared by the method according to claim 8 for catalyzing alcohol oxidation.
10. An alcohol fuel cell comprising the working electrode for alcohol electrochemical sensor according to claim 7 or the working electrode for alcohol electrochemical sensor prepared by the method according to claim 8; optionally, the alcohols include methanol, ethanol, ethylene glycol, and glycerol.
CN202210179935.5A 2022-02-25 2022-02-25 Working electrode for alcohol electrochemical sensor and preparation method thereof Pending CN114636740A (en)

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JP2011200748A (en) * 2010-03-24 2011-10-13 National Institute Of Advanced Industrial Science & Technology Catalyst for electrochemical oxidation of alcohol
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US20080314755A1 (en) * 2003-10-10 2008-12-25 Ohio University Layered electrocatalyst for oxidation of ammonia and ethanol
US20100099012A1 (en) * 2008-10-17 2010-04-22 Brookhaven Science Associates, Llc Electrocatalyst Synthesized by Depositing a Contiguous Metal Adlayer on Transition Metal Nanostructures
JP2011200748A (en) * 2010-03-24 2011-10-13 National Institute Of Advanced Industrial Science & Technology Catalyst for electrochemical oxidation of alcohol
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