A Co-S / Ni x Se y / C@TiO2 electrode and its preparation method and application

Abstract

The present invention belongs to the technical fields of electrode material preparation and electrochemical testing. In order to solve the problem of low electro-oxidation performance of H2O2, a Co-S / Ni x Se y / C@TiO2 electrode and its preparation method and application are provided. A layer of C@TiO2 nanoarray is grown on the Ti surface by chemical vapor deposition, and Ni x Se y nanoclusters and Co-S thin films are successively grown on the support by two-step electrodeposition to prepare a Co-S / Ni x Se y / C@TiO2 electrode. By rotating the static electrode plate, the problems of concentration polarization and bubbles occupying the active sites of the electrode are solved, thereby improving the electrode catalytic performance. The electrode prepared by the present invention is simple to operate and does not require a binder. The electrode has good electro-oxidation performance for catalyzing H2O2, excellent corrosion resistance and mechanical stability, and has broad application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical fields of electrode material preparation and electrochemical testing, and particularly relates to a Co-S / Ni x Se y / C@TiO2 electrode and its preparation method and application. The Co-S / Ni x Se y / C@TiO2 electrode is used for the electrocatalytic oxidation of H2O2 in a rotating cylinder three-electrode device, solving the problem of low electrooxidation performance of H2O2. Background Art

[0002] The energy problem has always been the key restricting human development. However, the earth's reserves of traditional fossil fuels are limited and there are environmental pollution problems. Therefore, people have been looking for new clean energy sources that can replace fossil fuels. Fuel cells can directly convert the chemical energy in oxidants and fuels into electrical energy and are not affected by the Carnot cycle. The advantages of high power generation efficiency and low environmental pollution of fuel cells make them an important device to replace traditional fossil fuels.

[0003] The oxygen element in H2O2 is in the -1 valence state. Therefore, in fuel cells, in addition to being an oxidant, fuel is also an important use. Compared with carbon-containing compounds (such as methanol and ethanol), H2O2 is a carbon-free compound composed of O and H. Therefore, greenhouse gases such as CO2 are not produced during the oxidation reaction, and at the same time, the phenomenon of catalyst CO poisoning is fundamentally solved. Moreover, compared with hydrogen, its storage and transportation are more convenient and safer. Therefore, direct hydrogen peroxide fuel cells have certain development prospects.

[0004] Ni and Co-based catalysts have the inherent advantage of low price and are potential materials for fuel cell anode catalysts, which have also attracted the attention of scholars in recent years. Compared with Ni or Co single-metal catalysts, due to the interaction between the two, the catalytic performance of bimetallic composite catalysts has been greatly improved compared with single-metal catalysts. However, due to the corrosion and oxidation of Ni and Co, the electrochemical performance is not satisfactory, and there is still a certain gap in its catalytic performance compared with noble metal catalysts such as Pt.

[0005] Transition metal chalcogenides have attracted more attention in the electrochemistry field due to their excellent electronic and optical properties. Moreover, compared with transition metal hydroxides or oxides, transition metal chalcogenides (mainly S and Se compounds) have higher electrical conductivity, and doping S-group elements into Ni and Co catalysts is an important way to improve their catalytic performance. In 2019, Jia et al. (Jia, J.; Zhao, L.; Chang, Y.; Jia, M.; Wen, Z. Understanding the growth of NiSe nanoparticles on reduced graphene oxide as efficient electrocatalysts for methanol oxidation reaction. Ceramics International 2020, 46 , 10023-10028.) prepared the NiSe / RGO catalyst, and due to the increase in the active sites of the Ni-based catalyst after selenization, NiSe / RGO has significant catalytic performance for methanol electrooxidation. In the study of Xu et al. (Xu, X.; Song, F.; Hu, X. A nickel iron diselenide-derived efficient oxygen-evolution catalyst. Nat Commun 2016, 7, 12324.), it was found that although the active substance would still transform into Ni oxides or hydroxides during the catalytic process, the catalytic activity was better when using Ni selenide as the precursor, and it has great application potential in the electrocatalysis field. In the work of Min et al. (Min, K.; Kim, S.; Lee, E.; Yoo, G.; Ham, H. C.; Shim, S. E.; Lim, D.; Baeck, S.-H. A hierarchical Co3O4 / CoS microbox heterostructure as a highly efficient bifunctional electrocatalyst for rechargeable Zn–air batteries. Journal of Materials Chemistry A 2021, 9, 17344-17352.), the Co3O4 / CoS catalyst was prepared. Compared with Co3O4, the Co3O4 / CoS catalyst after loading CoS has a higher double-layer capacitance, and in the electrochemical impedance spectroscopy measurement, the Rct of the Co3O4 / CoS catalyst is lower, the charge transfer between the electrode and the electrolyte is faster, and the electrocatalytic kinetic performance is more excellent.

[0006] However, the O2 generated by the oxidation of H2O2 and the gas generated by its decomposition will adhere to the surface of the electrode in the form of bubbles and are not easily detached with the flow of the reaction solution. The attached bubbles occupy the active sites of the catalyst and affect the catalytic effect of the catalyst on the electro-oxidation of H2O2. On the other hand, during the battery reaction process, the problem of reduced electrode performance caused by concentration polarization has always troubled fuel cell researchers.

[0007] As a means to enhance mass transfer and micro-mixing of liquids, the high gravity technology can promote gas evolution and mass transfer, and has received attention from researchers in recent years. In 1999, Mahito Atobe et al. first reported that the high gravity environment has a significant impact on the formation rate and performance of electrodeposited polyaniline films. In 2010, Liu Youzhi et al. from North University of China invented a multi-stage concentric cylinder-rotating bed type high gravity electrochemical reaction device that can be continuously operated in view of the problem that the existing high gravity electrochemical reaction devices are only limited to small-batch intermittent operations. The advantage of this device is that it can be continuously operated, is suitable for industrial application, and at the same time, the high gravity environment is conducive to the detachment of bubbles from the electrode surface and accelerates the mass transfer of substances in the reaction solution (CN201010033393.8). In 2012, Gao Jing et al. (Gao J, Liu YZ, Chang LF. Treatment ofPhenol Wastewater Using High Gravity Electrochemical Reactor with Multi-concentric Cylindrical Electrodes. China Pet. Process. Pe 2012, 14, 71-75.) used a multi-stage concentric cylinder-rotating bed type high gravity electrochemical reaction device to treat simulated phenol-containing wastewater with a concentration of 1000 mg·dm -3 -3, and the results showed that the electrolysis time in this reaction process was shortened by 55% compared with that in the conventional high gravity field, the phenol removal effect was improved by 50%, and the cost was reduced by 9.1%.

[0008] It can be seen that the high gravity environment has a good promoting effect on the electrolysis process. It is of great significance to combine the high gravity environment with the traditional three-electrolysis system to solve the problems of bubble attachment on the electrode surface and concentration polarization. Summary of the Invention

[0009] In order to solve the problem of low electro-oxidation performance of H2O2, the present invention provides a Co-S / Ni x Se y / C@TiO2 electrode and its preparation method and application. The Co-S / Ni x Se yThe / C@TiO2 electrode is used in a rotating cylinder three - electrode device for the electrocatalytic oxidation of H2O2.

[0010] The present invention is realized by the following technical solutions: A Co - S / Ni x Se y / C@TiO2 electrode. A layer of C@TiO2 nanorod array is grown on the Ti surface by chemical vapor deposition, and Ni x Se y nanoclusters and Co - S thin films are successively grown on the support by two - step electrodeposition to prepare the Co - S / Ni x Se y / C@TiO2 electrode.

[0011] The method for preparing the Co - S / Ni x Se y / C@TiO2 electrode is as follows:

[0012] (1) The Ti cylinder is ultrasonically treated in acetone, isopropanol, and ethanol for 15 min in sequence to remove the surface oil stain; then it is ultrasonically treated in a mixed acid of H2O:HNO3:HF = 5:4:1 until bubbles appear on the surface to remove the surface oxide layer;

[0013] (2) The pretreated Ti is placed in a tubular furnace, and N2 is introduced. Before entering the tubular furnace, N2 passes through ethanol liquid so that the N2 gas flow entering the tubular furnace carries ethanol. The electrode support C@TiO2 is prepared by chemical vapor deposition. The specific method is: Using N2 as the protective gas, the tubular furnace is heated to 850 °C at a rate of 5 °C / min, then ethanol / N2 is introduced at a gas flow rate of 100 ml / min and kept at 850 °C for 90 min. Finally, N2 is introduced and it is naturally cooled to room temperature to obtain the electrode support C@TiO2;

[0014] (3) Using the support C@TiO2 as the working electrode, a carbon rod as the counter electrode, and a silver / silver chloride electrode as the reference electrode, in a mixed electrodeposition solution of NiCl2·6H2O, SeO2, and LiCl, a traditional three - electrode system is adopted, and electrodeposition is carried out using a constant potential deposition method, controlling the sweep rate at 10 mV·s -1 , the deposition voltage is - 0.6~ - 1.0 V to prepare Ni x Se y / C@TiO2; Among them, in the mixed electrodeposition solution, the concentration of NiCl2·6H2O is 10~40 mmol·dm -3 , the concentration of SeO2 is 10~40 mmol·dm -3 , and the concentration of LiCl is 0.05~0.5 mol·dm -3 ;

[0015] (4) Using Ni x Se y / C@TiO2 as the working electrode, a carbon rod as the counter electrode, and a silver / silver chloride electrode as the reference electrode. In a mixed electrodeposition solution of Co(NO3)2·6H2O and CH4N2S, a traditional three-electrode system is used, and cyclic voltammetry is employed for electrodeposition. The scan rate is controlled at 10 mV·s -1 , the scanning range is -1.2 - 0 V, and it is scanned for 1 - 5 cycles to prepare the target electrode Co-S / Ni x Se y / C@TiO2; among them, in the electrodeposition solution, the concentration of Co(NO3)2·6H2O is 10 - 100 mmol·dm -3 , and the concentration of CH4N2S is 0.1 - 1 mol·dm -3 .

[0016] A rotating cylinder three-electrode device for testing electrode performance, comprising a sealed outer shell, a working electrode, a reference electrode, and a counter electrode. The working electrode uses the Co-S / Ni x Se y / C@TiO2 electrode or the prepared Co-S / Ni x Se y / C@TiO2 electrode. The working electrode is a rotating cylinder electrode, and the working electrode is fixed on a rotating disk arranged inside the sealed outer shell. The bottom of the rotating disk is connected to a motor arranged at the bottom outside the sealed outer shell. The motor is externally connected to a frequency converter, and the frequency converter controls the rotation speed of the motor, thereby controlling the rotation speed of the rotating disk and the working electrode;

[0017] The counter electrode is arranged at the center of the top of the sealed outer shell. The counter electrode is externally connected to a computer through an electrochemical workstation. A reference electrode is arranged on one side of the counter electrode at the top of the sealed outer shell, and a liquid inlet is arranged on the other side of the counter electrode;

[0018] A liquid outlet is opened at the bottom of the sealed outer shell corresponding to the side of the liquid inlet. The liquid inlet and the liquid outlet are connected by a liquid pump;

[0019] The counter electrode, the reference electrode, and the motor are respectively externally connected to a computer through an electrochemical workstation.

[0020] The motor and the rotating disk are connected by a carbon brush.

[0021] The working electrode is a cylinder with a diameter of 5 - 25 mm and a height of 10 - 100 mm. The sealed outer shell is made of insulating material.

[0022] The application of using the device for electrocatalytic oxidation of H2O2, the specific method is: the scanning range of cyclic voltammetry is -0.2 - 0.6 V, and the scanning speed is 10 mV·s-1 , the test solution is 0.1 - 3 mol·dm -3 NaOH and 0.1 - 3 mol·dm - 3 H2O2. The rotation speed of the working electrode is adjusted to 33 - 47 r / min through a frequency converter and a liquid pump -1 , and the circulating flow rate of the reaction solution is 0 - 800 ml / min -1 .

[0023] In the present invention, the preparation method of the electrode is simple, and it has excellent electrocatalytic activity, corrosion resistance, and mechanical stability; the rotating cylinder three - electrode test device is easy to operate, and can effectively solve the problem of the decrease in the electrode catalytic performance caused by the attachment of bubbles on the electrode surface and the concentration polarization of the reaction solution, and has a broad application prospect.

[0024] The present invention uses S - group elements to dope Ni and Co metals to achieve the synergistic effect between metals and non - metals to improve the electrode catalytic performance. C@TiO2 is used as the electrode support, which has good electrical conductivity; the Co - S / Ni x Se y active substance loaded on its surface has good catalytic performance for H2O2; at the same time, the rotating cylinder three - electrode device can remove the bubbles attached to the electrode surface, reduce the concentration polarization phenomenon of the reaction solution, and improve the catalytic performance of the electrode.

[0025] The present invention rotates the static electrode plate to solve the problems of concentration polarization and the occupation of the active sites of the electrode by bubbles, thereby improving the electrode catalytic performance. The electrode prepared by the present invention is simple to operate and does not require a binder. The electrode has good electro - oxidation performance for catalyzing H2O2, excellent corrosion resistance and mechanical stability, and has a broad application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is the process flow chart of the rotating cylinder three - electrode device;

[0027] In the figure: 1 - counter electrode; 2 - reference electrode; 3 - working electrode; 4 - rotating disk; 5 - motor; 6 - liquid outlet; 7 - liquid pump; 8 - liquid inlet; 9 - electrochemical workstation; 10 - computer; 11 - sealed housing, 12 - frequency converter;

[0028] Figure 2 is the cyclic voltammetry curve comparison diagram of the Co - S / Ni x Se y / C@TiO2 electrode prepared in Example 1 and other electrodes; Ni / C@TiO2, Ni x Se y / C@TiO2, Co - S / Ni x Se y / C@TiO2, Co-S / C@TiO2, Co-S / Ni x Se y The cyclic voltammograms of the / Ti electrode in 1 mol·dm -3 NaOH + 0.2 mol·dm -3 H2O2, scan rate = 10 mV·s -1 ;

[0029] Figure 3 is Co-S / Ni prepared in Example 2 x Se y The chronoamperometry curve of the / C@TiO2 electrode;

[0030] Figure 4 is Co-S / Ni prepared in Example 2 x Se y The chronoamperometry curves of the / C@TiO2 electrode at rest, electrode rotation speed of 37 r / min, and reaction solution circulation flow rate of 400 ml / min;

[0031] Figure 5 is Co-S / Ni in the rotating cylinder three-electrode device of Example 3 x Se y The comparison diagram of the electrode catalytic performance of the / C@TiO2 electrode with respect to rotation speed and reaction solution circulation flow rate; the reaction solution is 1 mol·dm -3 NaOH + 0.01 mol·dm -3 H2O2, sweep rate is 10 mV·s -1 . Detailed implementation manners

[0032] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which this invention belongs. All materials cited herein and their cited materials will be incorporated by reference.

[0034] Equivalent technologies of the specific implementation manners described that can be understood by those skilled in the art through routine experiments will be included in this application.

[0035] In the following examples, the experimental methods are conventional methods unless otherwise specified. The instruments and equipment used in the following examples are all conventional laboratory instruments and equipment unless otherwise specified; the experimental materials used in the following examples are all obtained from conventional biochemical reagent stores unless otherwise specified.

[0036] Example 1: Co-S / Ni x Se y / C@TiO2 electrode, a layer of C@TiO2 nanorod array was grown on the Ti surface by chemical vapor deposition method, and Ni x Se y nanoclusters and Co-S thin films were grown on the support in sequence by two-step electrodeposition method to prepare Co-S / Ni x Se y / C@TiO2 electrode.

[0037] The specific method is as follows:

[0038] The Ti sheet was cut into 10 mm×10 mm size, and the C@TiO2 support was prepared by chemical vapor deposition method. The Ti cylinder was pretreated by ultrasonic for 15 min in acetone, isopropanol and ethanol in sequence to remove the surface oil; then it was ultrasonicated in the mixed acid of H2O:HNO3:HF = 5:4:1 until bubbles appeared on the surface to remove the surface oxide layer.

[0039] The pretreated Ti was placed in a tube furnace, and ethanol / N2 mixed gas was introduced. The electrode support C@TiO2 was prepared by chemical vapor deposition method. The specific method is: using N2 as the protective gas, heating the tube furnace to 850 °C at a rate of 5 °C / min, then introducing ethanol / N2 at a gas flow rate of 100 ml / min and keeping it at 850 °C for 90 min, and finally introducing N2 and naturally cooling to room temperature to obtain the electrode support C@TiO2;

[0040] At room temperature (25±2 °C), with a carbon rod as the counter electrode, Ag / AgCl as the reference electrode, and the support C@TiO2 as the working electrode, the electrode was prepared. Ni x Se y / C@TiO2 electrode was prepared by potentiostatic deposition method to load Ni x Se y composite on 10 mm×10 mm C@TiO2. When the deposition solution composition was 20 mmol·dm -3 NiCl2·6H2O + 20 m mol·dm - 3 SeO2 + 0.1mol·dm -3In the electrolyte of LiCl, Ni was deposited on the C@TiO2 support by constant voltage deposition at a deposition potential of -0.8 V for 600 s. x Se y / C@TiO2.

[0041] Continue to use cyclic voltammetry to deposit Co-S on the Ni x Se y / C@TO2 electrode to prepare Co-S / Ni x Se y / C@TiO2 electrode. The deposition solution composition is 40 mmol·dm -3 Co(NO3)2·6H2O and 0.4 mol·dm -3 CH4N2S, and cyclic scanning is carried out 2 cycles between -1.2 - 0 V at a scan rate of 10 mV s -1 to deposit Co-S / Ni on the Ni x Se y / C@TiO2 electrode. x Se y / C@TiO2.

[0042] Using the Co-S / Ni x Se y / C@TiO2 electrode as the working electrode, a carbon rod as the counter electrode, and a silver / silver chloride electrode as the reference electrode, the electrocatalytic performance of H2O2 electrooxidation was tested by cyclic voltammetry.

[0043] The rotating cylinder three-electrode device for electrode performance testing is as Figure 1 shown, including a sealed outer shell 11, a working electrode 3, a reference electrode 2, and a counter electrode 1. The working electrode 3 uses the Co-S / Ni x Se y / C@TiO2 electrode prepared above. The working electrode 3 is a rotating cylinder electrode. The working electrode 3 is fixed on a rotating disk 4 arranged inside the sealed outer shell 11. The bottom of the rotating disk 4 is connected to a motor 5 arranged at the bottom outside the sealed outer shell 11. The motor 5 is externally connected to a frequency converter 12. The frequency converter 12 controls the rotation speed of the motor 5, and thus controls the rotation speed of the rotating disk 4 and the working electrode 3;

[0044] The counter electrode 1 is arranged at the center of the top of the sealed outer shell 11. The counter electrode 1 is externally connected to a computer 10 through an electrochemical workstation 9. A reference electrode 2 is arranged on one side of the counter electrode 1 at the top of the sealed outer shell 11, and a liquid inlet 8 is arranged on the other side of the counter electrode 1;

[0045] A liquid outlet 6 is opened at the bottom of the sealed outer shell 11 corresponding to one side of the liquid inlet 8. The liquid inlet 8 and the liquid outlet 6 are connected through a liquid pump 7;

[0046] The counter electrode 1, reference electrode 2, and motor 5 are respectively connected to an external computer 10 through an electrochemical workstation 9.

[0047] The motor 5 is connected to the rotating disk 4 through a carbon brush.

[0048] The test results of the electro-oxidation performance of the catalyst for H2O2 are as Figure 2 shown. In a 1.0 mol·dm -3 NaOH and 0.2 mol·dm -3 H2O2 solution, when the scanning rate is 10 mV·s -1 , and the potential is 0.6 V, the oxidation current density reaches 229.1 mA·cm -2 . Compared with Ni / C@TiO2, NiSe / C@TiO2, Co-S / C@TiO2, Co-S / Ni x Se y / Ti, the catalytic performance of the Co-S / Ni x Se y / C@TiO2 electrode is greatly improved, which is mainly due to the addition of Se and S elements and the special three-dimensional structure of the C@TiO2 substrate.

[0049] Example 2: A Co-S / Ni x Se y / C@TiO2 electrode was prepared in the same manner as in Example 1. The Co-S / Ni x Se y / C@TiO2 electrode was used as the working electrode, a carbon rod as the counter electrode, and a silver / silver chloride electrode as the reference electrode. The chronoamperometry method was used to test the catalytic stability of the electrode. The experimental results are as Figure 3 , Figure 4 shown. In a 2.0 mol·dm -3 NaOH and 0.4 mol·dm -3 H2O2 solution, when the scanning rate is 10 mV·s -1 , and the potential is 0.1 - 0.5 V, the chronoamperometric curve of the electrode is stable, indicating that the electrode has good corrosion resistance; as Figure 4 shown, in a 1.0 mol·dm -3 NaOH and 0.01 mol·dm -3 H2O2 solution, when the scanning rate is 10 mV·s -1 , and the potential is 0.1 - 0.5 V, the electrode catalytic performance is stable under the rotation speed and the reaction solution circulation flow rate, indicating that the electrode has good mechanical stability.

[0050] Example 3: Ti was cut and bent into a cylinder with a height of 20 mm and a diameter of 60 mm. The other electrode preparation steps were the same as those in Example 1. The prepared cylinder electrode was placed in a rotating cylinder three-electrode device in 1.0 mol·dm -3 NaOH and 0.01 mol·dm -3 H2O2 solution with a scanning rate of 10 mV·s -1 . The effects of different rotation speeds of the counter electrode and the circulation flow rate of the reaction solution on the catalytic performance of the electrode were compared, as shown in Figure 5 . When the rotation speed of the cylinder electrode was 37 r·min -1 , the oxidation current reached 554 mA. Compared with the static state, the catalytic current intensity of the electrode increased by 85%. It can be seen that adding a rotating effect to the counter electrode can effectively improve the catalytic performance of the electrode.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A Co-S / Ni x Se y / C@TiO2 electrode, characterized in that: A layer of C@TiO2 nanorod arrays was grown on the Ti surface by chemical vapor deposition, and Ni x Se y nanoclusters and Co-S thin films were successively grown on the support by two-step electrodeposition to prepare a Co-S / Ni x Se y / C@TiO2 electrode; The specific steps of the preparation method of the electrode are as follows: (1) The Ti cylinder is ultrasonically pretreated in acetone, isopropanol, and ethanol for 15 min in sequence to remove the oil stains on the surface; then it is ultrasonically treated in a mixed acid of H2O:HNO3:HF = 5:4:1 until bubbles appear on the surface to remove the surface oxide layer; (2) The pretreated Ti is placed in a tubular furnace, and N2 is introduced. Before entering the tubular furnace, N2 passes through ethanol liquid, so that the N2 gas flow entering the tubular furnace brings in ethanol. The electrode support C@TiO2 is prepared by chemical vapor deposition. The specific method is: using N2 as the protective gas, heating the tubular furnace to 850 °C at a rate of 5 °C / min, then introducing ethanol / N2 at a gas flow rate of 100 ml / min, and keeping it at 850 °C for 90 min. Finally, N2 is introduced and it is naturally cooled to room temperature to obtain the electrode support C@TiO2; (3) Using the support C@TiO2 as the working electrode, a carbon rod as the counter electrode, and a silver / silver chloride electrode as the reference electrode, in a mixed electrodeposition solution of NiCl2·6H2O, SeO2, and LiCl, a traditional three-electrode system was adopted, and potentiostatic electrodeposition was used for electrodeposition, controlling the scan rate at 10 mV·s -1 , with the deposition voltage ranging from -0.6 to -1.0 V, to prepare Ni x Se y / C@TiO2; among them, in the mixed electrodeposition solution, the concentration of NiCl2·6H2O was 10 - 40 mmol·dm -3 , the concentration of SeO2 was 10 - 40 mmol·dm -3 , and the concentration of LiCl was 0.05 - 0.5 mol·dm -3 ; (4) Use Ni x Se y / C@TiO2 as the working electrode, a carbon rod as the counter electrode, and a silver / silver chloride electrode as the reference electrode. In a mixed electrodeposition solution of Co(NO3)2·6H2O and CH4N2S, using the traditional three-electrode system, cyclic voltammetry is used for electrodeposition, controlling the scan rate at 10 mV·s -1 , the scanning range is -1.2 - 0 V, and scan 1 - 5 cycles to prepare the target electrode Co-S / Ni x Se y / C@TiO2; among them, in the electrodeposition solution, the concentration of Co(NO3)2·6H2O is 10 - 100 mmol·dm -3 , and the concentration of CH4N2S is 0.1 - 1 mol·dm -3 .

2. A rotating cylinder three - electrode device for electrode performance testing, comprising a sealed outer shell (11), a working electrode (3), a reference electrode (2) and a counter electrode (1), wherein the working electrode (3) uses the Co - S / Ni x Se y / C@TiO2 electrode, and is characterized in that: The working electrode (3) is a rotating cylinder electrode. The working electrode (3) is fixed on a rotating disk (4) arranged inside the sealed housing (11). The bottom of the rotating disk (4) is connected to a motor (5) arranged at the bottom outside the sealed housing (11). The motor (5) is externally connected to a frequency converter (12). The frequency converter (12) controls the rotation speed of the motor (5), and thus controls the rotation speeds of the rotating disk (4) and the working electrode (3); The counter electrode (1) is arranged at the center of the top of the sealed housing (11). The counter electrode (1) is externally connected to a computer (10) through an electrochemical workstation (9). A reference electrode (2) is arranged on one side of the counter electrode (1) at the top of the sealed housing (11), and a liquid inlet (8) is arranged on the other side of the counter electrode (1); A liquid outlet (6) is opened at the bottom of the sealed housing (11) on the side corresponding to the liquid inlet (8). The liquid inlet (8) is connected to the liquid outlet (6) through a liquid pump (7); The counter electrode (1), the reference electrode (2), and the motor (5) are respectively externally connected to a computer (10) through an electrochemical workstation (9).

3. The rotating cylinder three-electrode device for electrode performance testing according to claim 2, wherein: The motor (5) is connected to the rotating disk (4) through a carbon brush.

4. A rotating cylinder three-electrode device for electrode performance testing according to claim 2, characterized in that: The working electrode (3) is a cylinder with a diameter of 5 - 25 mm and a height of 10 - 100 mm.

5. The rotating cylinder three - electrode device for electrode performance testing according to claim 2, characterized in that: The sealed housing (11) is made of insulating material.

6. Application of the device according to claim 2 for electrocatalytic oxidation of H2O2, characterized in that: The specific method is as follows: The scanning range of cyclic voltammetry is -0.2~0.6 V, and the scanning speed is 10 mV·s -1 , and the test solution is 0.1~3 mol·dm -3 NaOH and 0.1~3 mol·dm -3 H2O2. The rotation speed of the working electrode is adjusted to 33 - 47 rmin through a frequency converter and a liquid pump -1 , and the circulation flow rate of the reaction solution is 0 - 800 mlmin -1 .

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