PtRhTe ternary alloy nanofiber material as well as preparation method and application thereof

Abstract

The invention discloses a PtRhTe ternary alloy nanofiber material and a preparation method and application thereof, the preparation method comprises the following steps: 1) taking Na2TeO3 as a raw material, hydrazine hydrate as a reducing agent and PVP as a dispersion stabilizer, adopting a hydrothermal method, then washing, centrifuging and dissolving in water to obtain a Te nanowire precursor solution; 2) centrifuging and washing the Te nanowire precursor to obtain a black precursor, and dissolving the black precursor in water to obtain a precursor solution; and 3) taking the precursor solution, taking ethylene glycol as a solvent, adding a rhodium chloride solution, carrying out a high-temperature oil bath reaction, then adding a chloroplatinic acid solution, carrying out a reaction for 1 h, and washing and drying the precipitate to obtain the PtRhTe ternary alloy nanofiber material. According to the method, a self-sacrifice template strategy is adopted, the prepared nanofiber material has a unique one-dimensional linear structure, and compared with a traditional method for preparing a hydrogen evolution electrocatalyst material, the method is simple in process step, easy to operate and capable of achieving large-scale production.

Description

Technical Field

[0001] The invention belongs to the technical field of electrocatalytic hydrogen evolution reaction catalysts, and specifically relates to a PtRhTe ternary alloy nanofiber material and a preparation method and application thereof. Background Art

[0002] With the development of human society, the three traditional energy sources (coal, oil, and natural gas) can no longer meet people's needs, and traditional energy will also have irreversible impacts on the climate and environment. Therefore, the research and development of new energy has attracted widespread attention. Hydrogen is considered to be an ideal energy carrier because of its advantages such as high energy density, recyclability, and green environmental protection. Hydrogen production by water electrolysis has the advantages of high product purity, simple process, and environmental friendliness, and has attracted much attention. In order to achieve efficient and stable hydrogen production by water electrolysis, excellent and stable hydrogen evolution catalysts are essential. In actual hydrogen production processes, many catalysts based on precious metals have been widely used due to their excellent catalytic performance. At present, the commercialized Pt / C is recognized as a hydrogen evolution catalyst with excellent performance, but its high price and scarce reserves also limit its large-scale application.

[0003] One-dimensional nanocrystalline materials (such as nanorods, nanotubes, and nanowires) exhibit a series of special optical, electrical, magnetic, and catalytic properties, and these properties are closely related to the size and morphology of the nanocrystalline materials themselves. The currently reported synthesis methods for this type of material mainly include template-assisted synthesis, vapor deposition, and colloidal chemistry. Template-assisted synthesis is to select porous materials with pore sizes ranging from nanometers to micrometers as templates, and combine electrochemical deposition, sol-gel, and chemical vapor deposition techniques to allow material atoms or ions to enter the nanoscale pores of the template, thereby forming the desired nanostructure. However, its limitation is that the premise of using template-assisted synthesis to prepare one-dimensional nanowires is that there must be a high-quality nanoscale pore template. The length, diameter, and morphology of the prepared nanowires are strictly restricted by the scale and morphology of the template, and it is difficult to obtain a one-dimensional nanowire structure with an ideal aspect ratio. Therefore, the development of low-cost and high-efficiency electrolytic water catalysts has become a problem that needs to be solved urgently. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention aims to provide a PtRhTe ternary alloy nanofiber material and its preparation method and application. The preparation method of the present invention is simple and universal, low in cost, and the obtained PtRhTe ternary alloy nanofiber material exhibits excellent electrocatalytic activity and stability.

[0005] In order to solve the problems of the prior art, the technical solution adopted by the present invention is:

[0006] A method for preparing a PtRhTe ternary alloy nanofiber material comprises the following steps:

[0007] Step 1: Preparation of Te nanowire precursor solution using a one-pot hydrothermal method

[0008] Sodium tellurite and PVP were added into water, stirred, and then ammonia water was added to adjust the pH, and hydrazine hydrate was added for reduction, and a Te nanowire precursor solution was prepared by a hydrothermal method;

[0009] Step 2, centrifuging and washing the Te nanowire precursor to obtain a black precursor, and dissolving it in water to obtain a precursor solution;

[0010] Step 3, using ethylene glycol as a solvent, adding rhodium chloride solution to the black precursor solution, reacting under high temperature oil bath conditions for 1 hour, adding chloroplatinic acid solution to continue the reaction, centrifuging, and washing and drying the precipitate to obtain PtRhTe ternary alloy nanofiber material.

[0011] As an improvement, the temperature of the hydrothermal method is 180°C.

[0012] As an improvement, the molar ratio of the black precursor, rhodium chloride and chloroplatinic acid in step 3 is 1:6:3.

[0013] As an improvement, the temperature of the high temperature oil bath in step 3 is 190° C. and the reaction time is 2 h.

[0014] The PtRhTe ternary alloy nanofiber material prepared by any of the above preparation methods is a one-dimensional linear structure, and Pt and Rh nanoparticles are uniformly grown on the precursor Te nanowire, the nanowire diameter is 20nm, and the interplanar spacing is 0.226nm, corresponding to the 101 crystal plane of PtRh. Te nanowires are used as reducing agents to distribute and replace Pt and Rh, thereby exerting the synergistic effect of the alloy, and the ultra-thin size unit with a diameter of 20nm can improve the utilization rate of Pt and Rh and provide more active sites; the self-sacrificial template method strategy enhances the stability of the hydrogen evolution catalytic reaction of the structure; the unique hollow linear structure can enhance the transmission and diffusion efficiency of electrons.

[0015] The above-mentioned PtRhTe ternary alloy nanofiber material is used as a catalyst in the electrocatalytic hydrogen evolution reaction.

[0016] Beneficial effects:

[0017] Compared with the traditional preparation method, the present invention prepares the one-dimensional nanowire structure of the PtRhTe ternary alloy by the template method, the process is simple and easy, easy to operate, and conducive to large-scale production; the obtained alloy nanofiber has uniform morphology. Compared with the traditional hydrothermal method and other methods, this method is simple and fast to operate, and the prepared alloy nanofiber material has uniform structure and high purity, which can realize large-scale production.

[0018] In addition, the PtRhTe ternary alloy nanofiber material prepared by the method of the present invention has the advantages of uniform morphology, excellent electrocatalytic activity, good stability, etc., and shows excellent electrocatalytic activity for hydrogen evolution reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a low-magnification SEM image of the PtRhTe ternary alloy nanofiber material prepared in Example 1;

[0020] Figure 2 This is an enlarged SEM image of the PtRhTe ternary alloy nanofiber material prepared in Example 1;

[0021] Figure 3 This is an enlarged TEM spectrum of the PtRhTe ternary alloy nanofiber material prepared in Example 1;

[0022] Figure 4 The XRD spectrum of the PtRhTe ternary alloy nanofiber material prepared in Example 1;

[0023] Figure 5 This is the XPS spectrum of the PtRhTe ternary alloy nanofiber material prepared in Example 1;

[0024] Figure 6 This is the XPS spectrum of the PtRhTe ternary alloy nanofiber material prepared in Example 1;

[0025] Figure 7 This is a comparison diagram of hydrogen evolution LSV of PtRhTe ternary alloy nanofiber material, Pt / C, PtTe, and RhTe;

[0026] Figure 8 It is a comparison diagram of the hydrogen evolution Tafel curves of PtRhTe ternary alloy nanofiber material, Pt / C, PtTe, and RhTe;

[0027] Fig. 9 This is a test diagram of the electrochemical stability of the PtRhTe ternary alloy nanofiber material prepared by the method of Example 1. DETAILED DESCRIPTION

[0028] The present invention is described in detail below in conjunction with specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0029] The experimental methods described in the examples are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0030] Example 1

[0031] A method for preparing a PtRhTe ternary alloy nanofiber material comprises the following steps:

[0032] 1) Preparation of Te nanowire precursor:

[0033] Weigh 0.095 g of sodium tellurite and 0.5 g of PVP (molecular weight 58,000) in 25 mL of water, stir mechanically for 10 min at room temperature to mix evenly, and then drop 3.35 ml of NH 3 ·H 2 O to adjust the pH, add 1.65 ml of hydrazine hydrate (mass fraction 50%), and then perform hydrothermal reaction in an oven at 180 °C for 3.5 h to obtain a Te nanowire precursor solution;

[0034] 2) After the Te nanowire precursor solution is centrifuged, the precipitate is washed with acetone to obtain a black precursor, which is dispersed in 30 ml of water to obtain a black Te nanowire precursor solution;

[0035] 3) Preparation of PtRhTe ternary alloy nanofiber materials by high temperature oil bath method:

[0036] Take 3 ml of the black Te nanowire precursor solution prepared in step 2), dissolve and disperse it in 27 ml of ethylene glycol solution after centrifugation, transfer it to a three-necked flask, add 0.25 mmol of rhodium chloride solution, and react in a high-temperature oil bath at 190°C for 1 hour; use a syringe pump to dropwise add 0.125 mmol of chloroplatinic acid solution and continue to react for 1 hour, naturally cool to room temperature, centrifuge, and wash the precipitate with ethanol 3 times to obtain the PtRhTe ternary alloy nanofiber material.

[0037] Example 2

[0038] Except that rhodium chloride solution and chloroplatinic acid solution are changed to 0.292mmol and 0.083mmol, all the other are the same as in Example 1.

[0039] Example 3

[0040] Except that rhodium chloride solution and chloroplatinic acid solution are changed to 0.333mmol and 0.042mmol, all the other are the same as in Example 1.

[0041] Example 4

[0042] Except that the oil bath temperature was changed from 190°C to 180°C, the rest was the same as in Example 1.

[0043] Example 5

[0044] Except that the oil bath temperature was changed from 190°C to 170°C, the rest was the same as in Example 1.

[0045] Example 6

[0046] Except that the oil bath temperature was changed from 190°C to 160°C, the rest was the same as in Example 1.

[0047] Comparative Example 1

[0048] The only difference from Example 1 is that a single metal Pt is used as the metal source, and the other implementation conditions remain unchanged, and it is named PtTe.

[0049] Comparative Example 2

[0050] The only difference from Example 1 is that a single metal Rh is used as the metal source, and the other implementation conditions remain unchanged, and it is named RhTe.

[0051] Take 2 mg of the catalyst prepared in Example 1 and Comparative Examples 1-2 respectively, add 1 ml of water and 0.1 ml of Nafion solution to prepare a catalyst solution, and evenly apply the prepared catalyst on the electrode surface to form an electrode, and perform the LSV test of the hydrogen evolution reaction of the corresponding test on Pt / C. The test method refers to the three-electrode test system. The selection range of the LSV test potential interval is set to -0.05V to -0.8V. The Tadel slope is obtained by data processing of the curve obtained by the LSV test. Fig. 9 The electrochemical stability test potential was set to -0.3 V and the test time was 20 h.

[0052] in, Figure 7 This is a comparison chart of the LSV of hydrogen evolution of different materials. It can be seen from the figure that the electrocatalytic materials of PtTe and RhTe alloy nanofibers both show worse hydrogen evolution performance than PtRhTe ternary alloy nanofibers, and PtRhTe ternary alloy nanofibers have the best hydrogen evolution performance.

[0053] Figure 8 This is a comparison chart of the hydrogen evolution Tafel curves of PtRhTe ternary alloy nanofiber material, Pt / C, PtTe, and RhTe. It can be seen from the figure that PtRhTe ternary alloy nanofiber has the smallest Tafel slope, proving that it has the best hydrogen evolution catalytic reaction activity.

[0054] Fig. 9 This is the electrochemical stability test diagram of the PtRhTe ternary alloy nanofiber material. It can be seen from the figure that the PtRhTe ternary alloy nanofiber has good catalytic stability for hydrogen evolution reaction.

[0055] In summary, the present invention prepares an electrocatalyst with excellent HER performance through a simple, self-sacrificial method that can be mass-produced. The selected reactants are cheap and readily available, and the process is simple and easy to operate. The sample has a fibrous structure and excellent reaction kinetics. The catalyst has good electrocatalytic activity and strong stability, and is a very potential catalyst for hydrogen evolution reaction with good application prospects.

[0056] The above is only a preferred specific implementation manner of the present invention, and the protection scope of the present invention is not limited thereto. Any simple change or equivalent replacement of the technical solution that can be obviously obtained by any technician familiar with the technical field within the technical scope disclosed in the present invention falls within the protection scope of the present invention.

Claims

1. A method for preparing a PtRhTe ternary alloy nanofiber material, characterized in that: The following steps are involved: Step 1: Preparation of Te nanowire precursor solution using a one-pot hydrothermal method Sodium tellurite and PVP were added into water, stirred, and then ammonia water was added to adjust the pH, and hydrazine hydrate was added for reduction, and a Te nanowire precursor solution was prepared by a hydrothermal method; Step 2, centrifuging and washing the Te nanowire precursor to obtain a black precursor, and dissolving it in water to obtain a precursor solution; Step 3, using ethylene glycol as a solvent, adding a rhodium chloride solution to a precursor solution, reacting under high-temperature oil bath conditions, adding a chloroplatinic acid solution dropwise using a syringe pump to continue the reaction, centrifuging, and washing and drying the precipitate to obtain a PtRhTe ternary alloy nanofiber material, wherein the amount of the Te nanowire precursor solution used is 2-4 ml.

2. The method for preparing a PtRhTe ternary alloy nanofiber material according to claim 1, characterized in that: The temperature of the hydrothermal method is 180°C.

3. The method for preparing a PtRhTe ternary alloy nanofiber material according to claim 1, characterized in that: The molar ratio of the black precursor, rhodium chloride and chloroplatinic acid in step 3 is 1:6:

3.

4. The method for preparing a PtRhTe ternary alloy nanofiber material according to claim 1, characterized in that: In step 3, the temperature of the high temperature oil bath is 190° C., and the reaction time is 2 h.

5. The PtRhTe ternary alloy nanofiber material prepared by any one of the preparation methods of claims 1 to 4, characterized in that: The PtRhTe ternary alloy nanofiber material is a one-dimensional linear structure, and Pt and Rh nanoparticles are uniformly grown on the precursor Te nanowires, with a particle diameter of about 20 nm and a crystal plane spacing of 0.226 nm, corresponding to the 101 crystal plane of PtRh.

6. Use of the PtRhTe ternary alloy nanofiber material according to claim 5 as a catalyst in a hydrogen evolution reaction.

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