阅读说明：本技术 一种利用等离子体增强MoS2电催化和/或光电催化性能的方法 (MoS (MoS) enhanced by utilizing plasma2Method for electrocatalytic and/or photoelectrocatalytic properties ) 是由 曹阳 张梦如 张瑞华 于 2021-01-18 设计创作，主要内容包括：本发明公开了一种利用等离子体增强MoS-2电催化和/或光电催化性能的方法,其特征在于,包括如下步骤：(1)制备MoS-2电催化和/或光电催化剂作为前驱体；(2)制备接收MoS-2催化剂反应信号的电极；(3)利用含C和F的等离子体对已经修饰在电极上的MoS-2催化剂进行改性。本发明显著提升了MoS-2的电催化和/或光电催化性能。该实验方法不仅简便、清洁,而且具有一定的普适性,可以应用于掺杂改性锂离子插层MoS-2、水热合成MoS-2、机械剥离2D MoS-2、化学气相沉积2D MoS-2等多种MoS-2电催化剂和/或光电催化剂,并且均实现了电催化和/或光电催化性能的显著提升,对plasma增强HER、OER、ORR等电化学和/或光电化学反应催化性能具有重要意义。(The invention discloses a method for enhancing MoS by using plasma 2 Method of electrocatalytic and/or photoelectrocatalytic properties, characterized in that it comprises the following steps: (1) preparation of MoS 2 Electrocatalysts and/or photocatalysts are used as precursors; (2) preparation receiving MoS 2 An electrode for a catalyst reaction signal; (3) using plasma containing C and F to treat MoS modified on electrode 2 And (4) modifying the catalyst. The invention obviously improves MoS 2 Electrocatalytic and/or photoelectrocatalytic properties. The experimental method is simple, convenient and clean, has certain universality, and can be applied to doping modified lithium ion intercalation MoS 2 Hydrothermal synthesis of MoS 2 Mechanical stripping of 2D MoS 2 Chemical vapor deposition of 2D MoS 2 Various MoS 2 The electrocatalyst and/or the photoelectric catalyst realize the remarkable improvement of the electrocatalysis and/or the photoelectric catalytic performance, and have important significance for the enhancement of the catalytic performance of electrochemical and/or photoelectrochemical reactions such as HER, OER, ORR and the like by plasma.)

1. MoS (MoS) enhanced by utilizing plasma₂Method of electrocatalytic and/or photoelectrocatalytic properties, characterized in that it comprises the following steps:

(1) preparation of MoS₂Electrocatalysts and/or photocatalysts are used as precursors;

(2) preparation receiving MoS₂An electrode that reacts to a signal;

(3) using plasma containing C and F to treat MoS modified on electrode₂And (4) modifying the catalyst.

2. The plasma enhanced MoS of claim 1, wherein the MoS is a semiconductor device₂Method of electrocatalytic and/or photoelectrocatalytic properties, characterized in that: the C and F containing plasma includes CHF₃、CH₂F₂、CH₃F、CF₄、C₃F₈、C₄F₈At least one of (1).

3. The plasma enhanced MoS of claim 1, wherein the MoS is a semiconductor device₂Electrocatalytic and/or photoelectrocatalytic propertiesA method of energy, characterized by: the plasma etching time is 10-600 s.

4. The plasma enhanced MoS of claim 1, wherein the MoS is a semiconductor device₂Method of electrocatalytic and/or photoelectrocatalytic properties, characterized in that: the kind of the plasma device includes one of radio frequency plasma, glow plasma, corona plasma, microwave plasma, DBD plasma.

5. The plasma enhanced MoS of claim 1, wherein the MoS is a semiconductor device₂Method of electrocatalytic and/or photoelectrocatalytic properties, characterized in that: the power of the plasma upper polar plate is 5-100W; the power of the lower electrode plate of the plasma is 1-50W.

6. The plasma enhanced MoS of claim 1, wherein the MoS is a semiconductor device₂Method of electrocatalytic and/or photoelectrocatalytic properties, characterized in that: the plasma gas flow rate is 10-100 sccm.

7. The plasma enhanced MoS of claim 1, wherein the MoS is a semiconductor device₂Method of electrocatalytic and/or photoelectrocatalytic properties, characterized in that: the pressure of the cavity is 1-20Pa when the plasma works.

8. The plasma enhanced MoS of claim 1, wherein the MoS is a semiconductor device₂Method of electrocatalytic and/or photoelectrocatalytic properties, characterized in that: precursor MoS₂Intercalation MoS containing lithium ion₂Hydrothermal synthesis of MoS₂Mechanical stripping of 2D MoS₂Chemical vapor deposition of 2D MoS₂Internal MoS₂At least one of an electrocatalytic and/or a photo-catalytic.

9. The plasma enhanced MoS of claim 1, wherein the MoS is a semiconductor device₂Method of electrocatalytic and/or photoelectrocatalytic properties, characterized in that: receiving MoS₂The electrode for reaction signal comprises hydrophilic carbon cloth and O₂At least one of hydrophobic carbon cloth treated by plasma, foamed nickel, foamed copper, pure metal electrodes evaporated by electron beams or heat, ITO conductive transparent glass and FTO conductive transparent glass.

10. A plasma enhanced MoS according to any of claims 1 to 9₂Method of electrocatalytic and/or photoelectrocatalytic properties, characterized in that: further comprises the step (4) of plasma-MoS₂Electrocatalytic and/or photoelectrocatalytic tests including HER, OER were performed.

Technical Field

The invention relates to the field of electrocatalytic and/or photoelectrochemical catalytic materials, in particular to a method for preparing a composite material by usingPlasma enhanced MoS₂A method of electrocatalytic and/or photoelectrocatalytic properties.

Background

Energy is the driving force of industrial revolution and is an indispensable strategic resource. In a large family of renewable energy sources, hydrogen energy has a high heat of combustion value, the combustion product H₂And O can be recycled. The hydrogen production by electrolyzing water is one of the most promising effective ways for producing hydrogen at present, and can realize the simultaneous and separate production of H at the cathode₂The anode produces O₂. However, due to the high reaction energy barrier and reaction obstruction, the voltage required to be applied in an actual electrocatalysis test system is larger than the theoretical reaction voltage, so that the introduction of a catalyst with high catalytic activity, high stability, low price and wide sources can obviously reduce the reaction activation energy and improve the reaction efficiency, and is a key factor for realizing high-efficiency water electrolysis.

The Pt and Ru-based noble metal-based catalyst is the electrocatalytic Hydrogen Evolution (HER), Oxygen Evolution Reaction (OER) and oxygen reduction (ORR) catalyst with the best performance at present, but cannot be applied in large scale in industrial production due to high price and rare reserves.

In volcano, MoS₂Gibbs free energy of hydrogen adsorption Δ G in all non-noble metal-based catalysts_HMoS in non-noble metal catalysts, closest to 0, also to Pt-based catalysts₂Exchange current density is the largest and catalytic performance is the best, so that the Pt-based catalyst is expected to be replaced theoretically. And, MoS₂Is a semiconductor with special energy band structure, single-layer MoS₂Is a direct band gap semiconductor with a band gap of 1.8eV, non-single layer and bulk MoS₂An indirect bandgap semiconductor of 1.29eV when the photon energy of the incident light is higher than MoS₂At absorption threshold, MoS₂Valence electrons are transited from a valence band to a conduction band, so that holes and electrons are generated, the holes adsorb negative electricity central substances such as hydroxyl on the surface of the electrode, and then the photoelectrocatalytic OER reaction is generated.

However, in electrocatalytic HER and photoelectrocatalytic OER applications, MoS₂The edge active sites are limited, and the photon-generated carriers are easy to recombine, thereby greatly limiting the popularization of the methodAnd applications thereof.

Disclosure of Invention

The invention mainly aims to provide a plasma enhanced MoS₂The method for electrocatalysis and/or photoelectrocatalysis performance provides a clean, simple, convenient, rapid and controllable research strategy for the catalytic performance of the in-situ modified catalyst, avoids organic and inorganic solvent pollution caused by a chemical modification method in a liquid phase system, and further avoids the influence of the pollution on an electrode-electrolyte interface double electric layer and the electrocatalysis and/or photoelectrocatalysis performance.

In order to achieve the purpose, the invention adopts the following technical scheme:

MoS (MoS) enhanced by utilizing plasma₂A method of electrocatalytic and/or photoelectrocatalytic performance comprising the steps of:

(1) preparation of MoS₂Electrocatalysts and/or photocatalysts are used as precursors;

(2) preparation receiving MoS₂An electrode that reacts to a signal;

(3) using plasma containing C and F to treat MoS modified on electrode₂And (4) modifying the catalyst.

Preferably, the plasma etch time is 10-600 s. The plasma etching time is not suitable to be too long or too short, the catalyst can be seriously peeled off when the plasma processing time is more than 600s, and the doping degree of the catalyst is too low and the highest activity can not be achieved when the plasma processing time is less than 10 s.

In a preferred embodiment, the C and F containing plasma comprises CHF₃、CH₂F₂、CH₃F、CF₄、C₃F₈、C₄F₈At least one of (1).

In a preferred embodiment, the species of plasma device comprises radio frequency plasma, glow plasma, corona plasma, microwave plasma, DBD plasma.

In a preferred embodiment, the power of the plasma upper plate is 5-100W; the power of the lower electrode plate of the plasma is 1-50W.

In a preferred embodiment, the plasma gas flow rate is 10-100 sccm.

In a preferred embodiment, the chamber pressure during operation of the plasma is between 1 Pa and 20 Pa.

In a preferred embodiment, the precursor MoS₂Intercalation MoS containing lithium ion₂Hydrothermal synthesis of MoS₂Mechanical stripping of 2D MoS₂Chemical vapor deposition of 2D MoS₂Internal MoS₂At least one of an electrocatalytic and/or a photo-catalytic.

In a preferred embodiment, MoS is received₂The electrode for photocatalysis and/or electric reaction signal comprises hydrophilic carbon cloth and O₂Plasma treated hydrophobic carbon cloth, nickel foam, copper foam, pure metal electrodes electron beam or thermal evaporation, ITO transparent conductive glass, FTO transparent conductive glass, etc.

In a preferred embodiment, the method further comprises the step (4) of plasma-MoS₂Electrochemical and/or photoelectrochemical tests including HER, OER were performed.

The invention has the beneficial effects that:

the invention uses C and F containing plasmas to pair MoS which has been modified on an electrode₂Modification of electrocatalysts and/or photocatalysts, C-and F-containing plasmas such as CHF₃Widely used for Si substrate etching in the semiconductor industry, but no one has proposed it for modifying MoS₂Catalysts, CHF therefor₃The process of using a gas-inclusive C and F containing plasma as a plasma gas source is very novel.

Plasma modified MoS containing C and F₂The advantages of the electrocatalyst and/or the photocatalyst are: CHF₃The gas can increase MoS by etching₂High catalytic activity edge site number, and MoS can be doped by F element₂The catalytic performance is improved, and the catalyst can also be applied to MoS through C element₂The outer layer forms a carbon layer to enhance stability. Thus, the MoS obtained by the process of the invention₂The catalyst has excellent electrocatalytic and/or photoelectrocatalytic activity and stability.

The invention utilizes the presence of C and F in a plasmaActive substances such as atoms, ions, active free radicals and the like in an excited state react with the surface of the material to dope and functionalize the material so as to realize the promotion of electrocatalytic and/or photoelectrocatalytic activity. Comparative intrinsic MoS₂The method is used for modifying various types of MoS by utilizing plasma technology₂Electrocatalysts and/or photocatalysts, plasma-MoS obtained₂Exhibit higher current densities; plasma-MoS₂The method has a smaller Tafel curve slope, and the reaction kinetics are obviously improved; plasma-MoS₂The overpotential of the reaction is successfully reduced, and the potential barrier to be overcome by the reaction is greatly reduced.

The method has the advantages of simple and easy operation, high controllability and repeatability, and capability of simply, conveniently and efficiently directly utilizing gas-phase active substances such as excited ions, atoms, free radicals and the like to realize MoS₂Surface modification of (2). Compared with other chemical methods for modifying the surface of a material, the plasma method not only has the advantages of simplicity, cleanness and high selectivity, but also can change reaction conditions very easily and efficiently by changing parameters such as gas types, pressure, ICP power, RF power, time and the like. In addition, the method has certain universality, and is applied to various forms of MoS such as a lithium ion intercalation method, a hydrothermal synthesis method, a mechanical stripping method, a chemical vapor deposition method and the like₂The surface modification of the electrocatalyst and/or the photoelectric catalyst realizes the obvious improvement of the performance.

Drawings

The invention is further illustrated by the following figures and examples.

FIG. 1: example 1(a-b) original MoS₂(ii) a (c-d) plasma-MoS₂SEM image of

FIG. 2: example 1 original MoS₂With plasma-MoS₂Comparison of LSV test results

FIG. 3: example 1 original MoS₂With plasma-MoS₂Of 10mA/cm²Over potential contrast of

FIG. 4: example 1 original MoS₂With plasma-MoS₂Tafel plot comparison of (1);

FIG. 5: example 1 original MoS₂With plasma-MoS₂EIS AC impedance Spectrum (-0.3V vs RHE test)

Detailed Description

While the present invention will be described with respect to particular embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but is intended to cover by the appended claims the scope of the invention, and that certain changes in the embodiments of the invention will be suggested to those skilled in the art, which, in light of the foregoing description, are intended to be covered by the appended claims.

Example 1: MoS method for modifying lithium ion intercalation by using plasma₂HER catalytic performance of

First step, preparation of MoS₂Electrocatalyst dispersion: 3mL of 2mg/mL MoS₂Adding 1800 μ L of absolute ethyl alcohol and 200 μ L of Nafion into the water solution, and performing ultrasonic dispersion for 30 min. Second, preparation of MoS-loaded₂Working electrode of catalyst: cutting the hydrophilic carbon cloth into 1cm by 2cm, washing with water, IPA and absolute ethyl alcohol in sequence, and drying for later use. 100uL of the dispersion liquid is uniformly dripped on carbon cloth, and the solution is dried at 60 ℃ and repeated once. Heating for 3h to enhance the bonding of the catalyst and the substrate and reduce the falling off of the catalyst during the plasma treatment process, wherein the loading is 0.05mg/cm². Thirdly, using plasma technology to treat MoS₂Surface treatment of HER catalyst: fixing carbon cloth on a Cu foil adhered with heat-conducting silica gel, wherein the Cu foil is used as a carrier to assist the carbon cloth to stand in a plasma cavity to realize vertical etching of plasma, so that the phenomenon that a catalyst falls off due to the fact that the catalyst is bombarded by the plasma in the horizontal direction is avoided, the power of an upper polar plate ICP is 100W, the power of a lower polar plate RF is 50W, the pressure of the cavity is 10Pa, and gaseous CHF (CHF)₃The flow is 80sccm, the etching time is 30s, the plasma etching time is not too long or too short, the catalyst is seriously peeled off due to too long plasma treatment time, and the doping degree of the catalyst is too low and the highest activity cannot be achieved due to too short plasma treatment time.

Fourth, plasma-MoS₂HER test was performed: by classical three-electrode electrochemicalThe chemical system uses Pt electrode clamp to fix carbon cloth as working electrode, carbon rod as counter electrode, Ag/AgCl electrode as reference electrode to perform HER test, and electrolyte is 0.5M H₂SO₄。

The results of this example are shown in fig. 1 to 5.

Example 2: MoS (metallothionein) synthesis method by utilizing plasma modification hydrothermal method₂HER catalytic performance of

Step one, MoS is uniformly grown on carbon cloth by a hydrothermal method₂Micron sheet: 0.3g of ammonium molybdate tetrahydrate and 0.3g of thiourea are respectively used as a Mo source and an S source, are uniformly dispersed in 20mL of ultrapure water, and are subjected to ultrasonic dispersion for 10 min. Second step, O₂Plasma treatment of the growth substrate to prepare a MoS-loaded substrate₂Working electrode of catalyst: cutting the hydrophilic carbon cloth into 1cm by 2cm, washing with water, IPA and absolute ethyl alcohol in sequence, and drying for later use. By using O₂Plasma treatment of the front and back surfaces of the carbon cloth, on the one hand, oxygen-containing functional groups are introduced to further enhance the hydrophilicity of the carbon cloth, and on the other hand, negatively charged oxygen-containing functional groups are beneficial to adsorption of relatively positively charged thiourea central carbon atoms, so that MoS is achieved₂The growth is more uniform. O is₂The plasma power is 50W, the time is 60s, the cavity pressure is 100Pa, and after treatment, the carbon cloth is quickly put into the solution in the first step and is subjected to ultrasonic treatment for 30-60 min. Then the mixture is put into a 100mL reaction kettle inner container and reacted for 18h at 180 ℃. Thus obtaining the molybdenum disulfide micron sheet evenly coated on the carbon cloth fiber. Thirdly, using plasma technology to treat MoS₂Surface treatment of HER catalyst: fixing carbon cloth on a Cu foil adhered with heat-conducting silica gel, wherein the Cu foil is used as a carrier to assist the carbon cloth to stand in a plasma cavity to realize vertical etching of plasma, so that the phenomenon that a catalyst falls off due to the fact that the catalyst is bombarded by the plasma in the horizontal direction is avoided, the power of an upper polar plate ICP is 100W, the power of a lower polar plate RF is 50W, the pressure of the cavity is 10Pa, and gaseous CHF (CHF)₃The flow rate was 80sccm and the etching time was 30 s. Fourth, plasma-MoS₂HER test was performed: a classical three-electrode electrochemical system is adopted, a Pt electrode clamp is used for fixing carbon cloth as a working electrode, a carbon rod is used as a counter electrode, an Ag/AgCl electrode is used as a reference electrode for HER test,electrolyte solution of 0.5M H₂SO₄. Similar to example 1, this example also passed CHF_3-Plasma to MoS₂The catalytic performance of HER is obviously improved, and the current density is improved by 2 times.

Example 3: 2D MoS using plasma modified mechanical stripping₂HER catalytic performance of

First, the Scotch tape is applied to SiO₂Peeling off the substrate to obtain a 2D MoS with a length and a width of about 50 micrometers and 50 micrometers respectively₂. Second, 2D MoS₂Connected with a metal electrode as a receiving 2D MoS₂Electrochemical reaction signal of HER catalyst. Thirdly, the 2D MoS is processed by utilizing the plasma technology₂Surface treatment of HER catalyst: 2D MoS₂-SiO₂Horizontally placing into a plasma cavity, wherein the power of an upper plasma plate ICP is 100W, the power of a lower plasma plate RF is 50W, the pressure of the cavity is 10Pa, and the gas CHF₃The flow rate was 80sccm and the etching time was 30 s. Fourth, plasma-MoS₂HER test was performed: adopting a three-electrode electrochemical system to connect with 2D MoS₂The metal electrode is used as a working electrode, the Pt wire is used as a counter electrode, the Ag/AgCl electrode is used as a reference electrode for HER test, and the electrolyte is 0.5M H₂SO₄. Similar to examples 1 and 2, this example also passed CHF₃Plasma enabled 2D MoS₂The catalytic performance of HER is obviously improved, and the current density is improved by 4.5 times.

Example 4: 2D MoS using plasma modified chemical vapor deposition₂HER catalytic performance of

Firstly, Mo foil and S are used as raw materials to obtain large-area 2D MoS through chemical vapor deposition growth₂. Second, 2D MoS₂Connected with a metal electrode as a receiving 2D MoS₂Electrochemical reaction signal of HER catalyst. Thirdly, the 2D MoS is processed by utilizing the plasma technology₂Surface treatment of HER catalyst: 2D MoS₂-SiO₂Horizontally placing into a plasma cavity, wherein the power of an upper plasma plate ICP is 100W, the power of a lower plasma plate RF is 50W, and the cavity pressure isForce of 10Pa, gaseous CHF₃The flow rate was 80sccm and the etching time was 30 s. Fourth, plasma-MoS₂HER test was performed: adopting a three-electrode electrochemical system to connect with 2D MoS₂The metal electrode is used as a working electrode, the Pt wire is used as a counter electrode, the Ag/AgCl electrode is used as a reference electrode for HER test, and the electrolyte is 0.5M H₂SO₄. Similar to examples 1, 2 and 3, this example also passed through CHF₃Plasma enabled 2D MoS₂The catalytic performance of HER is obviously improved, and the current density is improved by 3 times.

Example 5: hydro-thermal synthesis MoS by utilizing plasma modification₂OER photoelectrocatalytic performance of

First step, synthesis of MoS by hydrothermal method₂Micron sheet: 0.3g of ammonium molybdate tetrahydrate and 0.3g of thiourea are respectively used as a Mo source and an S source, are uniformly dispersed in 20mL of ultrapure water, and are subjected to ultrasonic dispersion for 10 min. Then the mixture is put into a 100mL reaction kettle inner container and reacted for 18h at 180 ℃. The MoS with uniform size distribution can be obtained₂And (4) micro-spheres. Then 10mg/mL MoS is prepared₂Catalyst dispersion to which 20mg MoS was added₂Catalyst, 1mL deionized water, 1800 mu L absolute ethyl alcohol and 200 mu L Nafion, and ultrasonically dispersing for 30 min. Second step, O₂Plasma treatment of FTO conductive transparent glass to prepare MoS-loaded articles₂Transparent working electrode of catalyst: cutting the FTO conductive transparent glass into 1cm by 2cm by using a diamond cutting tool, cleaning by using water, IPA and absolute ethyl alcohol in sequence, and drying for later use. By using O₂Plasma treatment of the surface of the FTO conductive transparent glass standing vertically, on the one hand, introduction of oxygen-containing functional groups further enhances the hydrophilic properties of the FTO conductive glass, and on the other hand, facilitates the close contact between the catalyst dispersion and the FTO, reduces the interface contact resistance and MoS in the subsequent plasma treatment process₂The catalyst is dropped off. O is₂Plasma power 50W, time 60s, chamber pressure 100 Pa. Dispensing 50 mu LMoS₂And heating the catalyst dispersion liquid on the surface of the FTO conductive glass at 60 ℃ for 5 hours to volatilize the solvent and enhance the contact. Thirdly, using plasma technology to treat MoS₂Carrying out surface treatment on the OER photoelectric catalyst: fixing and standing FTO conductive transparent glass in a plasma chamberThe vertical etching of plasma is realized in the body, the phenomenon that the catalyst falls off due to the fact that the catalyst is bombarded by the plasma too strongly in the horizontal direction is avoided, the power of an upper polar plate ICP is 20W, the power of a lower polar plate RF is 5W, the pressure of a cavity is 10Pa, and the gas CHF₃The flow rate was 35sccm and the etching time was 30 s. Fourth, plasma-MoS₂OER photoelectrocatalytic testing was performed: adopting a classical three-electrode electrochemical system, fixing FTO conductive transparent glass as a working electrode by a Pt electrode clamp, taking a Pt sheet counter electrode as well as an HgO electrode as a reference electrode, and carrying out an OER (optical electronic Equipment) photoelectrocatalysis test in a specially-made photoelectrocatalysis reaction tank to ensure that simulated sunlight vertically irradiates on the FTO conductive transparent glass, wherein the power of the simulated sunlight is 100mW cm^-2The electrolyte was 0.1M NaOH. Similar to examples 1, 2, 3, 4, this example also passed through CHF₃Plasma to MoS₂The OER photoelectrocatalysis performance is obviously improved, and the open photocurrent is increased by 12.3 times.