Method for chemical vapor deposition of oxygen-containing cobalt sulfide cathode and application

Abstract

The invention relates to the application fields of catalyst preparation, performance detection and sterilization and pollutant degradation, and particularly discloses a method for chemical vapor deposition of an oxygen-containing cobalt sulfide cathode, which comprises the following steps: introducing a mixed carrier gas of a shielding gas and a reducing gas into a tubular furnace, and carrying out programmed heating to a preset high temperature to enable CoCl2 to react with S, vapor deposition is performed on a clean conductive substrate. After the reaction is finished, cutting off the reducing gas, and temporarily introducing air to slightly oxidize the sample, so as to directly obtain an electrochemical catalytic reaction cathode of the CoSOX / conductive substrate; the CoSOX / conductive substrate overcomes the defects that CoS is poor in stability, easy to oxidize and weak in adsorption capacity and CoO is weak in catalytic capacity and poor in conductivity, a large amount of < 1 > O2 can be stably and efficiently generated to kill harmful pathogenic bacteria in a water body in a broad-spectrum mode and effectively degrade organic pollutants such as rhodamine B, methyl orange and methylene blue, and the electrocatalytic sterilization system has extremely high practical application value.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of catalyst preparation and performance detection and sterilization and pollutant degradation applications, in particular to a method for chemical vapor deposition of cobalt oxysulfide cathode and application, the above-mentioned cathode electrode can be used as a cobalt oxysulfide polyhedral electrochemical catalyst, which can stably and efficiently generate 1 O2 under the condition of power supply, achieving the purpose of sterilization and pollutant degradation. BACKGROUND

[0002] With the acceleration of global urbanization and the continuous growth of population, water resource shortage and water pollution problems are becoming increasingly serious, and the incidence of water-borne diseases remains high. This not only poses a serious threat to human health, but also has a negative impact on social and economic development. Therefore, it is particularly urgent to develop efficient, environmentally friendly and sustainable water treatment sterilization technology. Traditional sterilization methods, such as chlorination disinfection, face the problems of the emergence of chlorine-resistant pathogens and the generation of disinfection by-products. Ozone disinfection has the challenges of short disinfection time, unsafe transportation, high operating costs and possible generation of harmful by-products. Therefore, finding a new sterilization technology that can efficiently inactivate pathogens in water without generating secondary pollution is of great significance for ensuring the safety of drinking water, protecting the ecological environment and promoting sustainable development.

[0003] Among the many sterilization mechanisms, 1 O2 is considered one of the most promising sterilization mechanisms due to its unique physical and chemical properties and high sterilization capacity. 1 O2 has high reactivity, long lifetime and low by-product generation characteristics, and can quickly react with biological macromolecules in microbial cells, destroying the physiological structure and metabolic function of cells, thereby achieving efficient inactivation of bacteria, viruses and fungi and other microorganisms. Compared with other active oxygen free radicals, 1 O2 has higher selectivity for microorganisms and less impact on the environment, and can maintain stable sterilization effect in a wide pH range. In addition, 1 The generation process of O2 is relatively green and sustainable, which can be directly generated from oxygen by electrocatalysis and other methods without adding additional chemical reagents, reducing the risk of secondary pollution to the environment. Therefore, the sterilization mechanism based on O2 is considered one of the best choices in the current water treatment field. 1

[0004] Cobalt-based (Co) catalysts are the key to realizing the activation of oxygen to generate 1 ​One of the most potential metals of O2, due to its unique electronic structure and multivalent state characteristics, exhibits high efficient catalytic performance in electrocatalytic production of active oxygen, effectively promotes the activation and conversion of oxygen molecules by reducing the reaction overpotential and providing active sites, and provides important technical support for environmental governance and energy conversion fields. Among them, the most widely studied are CoS and CoS, however, due to their respective defects, their further development is limited. CoS has good conductivity and catalytic performance, but its stability is poor, the surface is easy to be oxidized, and the activity will decrease with time. CoO has good stability and adsorption capacity, but poor conductivity and low catalytic efficiency. SUMMARY

[0005] In view of the problems of poor stability and easy oxidation of the surface of CoS catalyst and poor conductivity and low catalytic efficiency of CoO catalyst in cobalt-based catalysts, the present application provides a method for chemical vapor deposition of cobalt oxysulfide cathode, and the above-mentioned cathode electrode can be used as a cobalt oxysulfide polyhedral electrochemical catalyst. In the present application, high-ordered pyrolytic graphite (HOPG) as a substrate has high crystallinity and surface flatness, excellent conductivity and thermal conductivity, good chemical stability, easy handling and cleaning, and can be reused. One-step vapor deposition is directly carried out on the surface of HOPG, and the obtained cobalt oxysulfide / high-ordered pyrolytic graphite (CoSO X / HOPG) can be directly used as an electrode for electrocatalysis. At the same time, CoSO X / HOPG overcomes the defects of CoS and CoO, and can efficiently and stably produce O2 for water disinfection or degradation of wastewater pollutants. 1

[0006] In order to achieve the above-mentioned purpose, the present application comprises the following technical solutions:

[0007] A method for chemical vapor deposition of cobalt oxysulfide cathode, comprising the following steps:

[0008] (1) Clean the surface of the conductive substrate to be free of impurities, and the conductive substrate is selected from one of HOPG, sapphire, mica sheet or nickel foil.

[0009] Preferably, first, the upper and lower surfaces of the substrate are peeled off with adhesive tape, and the substrate is placed under a metallographic microscope to ensure that the upper and lower surfaces are free of impurities and pollutants;

[0010] (2) Place the substrate at the center of the downstream 1-3 cm of the constant temperature zone of the tube furnace, place CoCl2 and sulfur powder in corundum boats respectively, and place them at the center of the upstream 1-3 cm of the constant temperature zone, and the sulfur powder boat is tightly attached to the wall of the furnace and is controlled by an independent heating belt.

[0011] ​Preferably, the substrate is placed 1-3 cm downstream from the center point of the constant temperature zone of the tube furnace, 2 g of CoCl2 and sufficient amount of sulfur powder (to ensure sufficient sulfur source) are placed in corundum boats 1-3 cm upstream from the center point of the constant temperature zone, the corundum boat containing the sulfur powder is placed outside the tube furnace hearth next to the furnace wall, and the heating time and temperature of the sulfur powder are controlled by a separate heating belt.

[0012] (3) After vacuumizing for a certain time, the tube is purged with Ar multiple times to remove air in the tube;

[0013] Preferably, before the reaction formally starts, the air in the tube needs to be removed. First, the tube furnace is vacuumized to the limit pressure and maintained for more than 10 min, then backfilled with Ar to the ambient pressure. This cleaning cycle is repeated 3 times to ensure that the air in the tube furnace is completely removed.

[0014] (4) The mixed carrier gas containing the reducing component is introduced, and when the pressure reaches 5000-20000 Pa, the sulfur powder is heated to complete melting and maintained for ≥10 min;

[0015] Preferably, the mixed gas with a ratio of Ar to H2 of about 5:1 is used as the carrier gas during growth, and when the pressure reaches 5000-20000 Pa, the sulfur powder is heated to complete melting and maintained for 10 min, and the sulfur vapor is introduced into the growth area in advance before heating CoCl2;

[0016] (5) The temperature is programmed to 800-850℃ and maintained for deposition of cobalt sulfide containing oxygen;

[0017] Preferably, the temperature is programmed to raise the tube furnace to 800-850℃ within 35 min, and maintained at this temperature for 5 min for deposition of CoSO X .

[0018] (6) Stop supplying reducing gas and sulfur, and introduce inert gas to remove impurities;

[0019] Preferably, after the reaction is completed, H2 is immediately turned off, the heating jacket is turned off to stop the supply of sulfur, the Ar flow is increased to remove impurities in the furnace, and the sample is protected from damage

[0020] (7) Introduce oxygen-containing gas for oxidation treatment, and obtain the cathode electrode after cooling.

[0021] Preferably, the vacuum pump and vacuum valve are turned off, the gas inlet device is disassembled, air is introduced, the material is oxidized at 750-800℃ for 10-15 min, then the heating system is turned off to wait for the end of cooling, and the sample is taken out. When HOPG is used as the raw material conductive substrate, the product is named CoSO X / HOPG, which can be directly used as a cathode electrode.

[0022] This invention also discloses an electrochemically activated O2 cathode electrode, prepared by any of the above methods, and having the following characteristics:

[0023] Cobalt oxide (CoSO₄) X The particles are distributed on the substrate surface in a regular polyhedral structure with a particle size of 1-2 μm.

[0024] The composite structure contains an amorphous CoO layer formed by in-situ oxidation.

[0025] Furthermore, the aforementioned cathode electrode can efficiently and stably generate singlet oxygen at a potential of -0.8V (vs. Ag / AgCl). 1 O2).

[0026] The present invention also discloses an electrochemical catalytic system, comprising:

[0027] Double-chamber H-type electrolytic cell;

[0028] The anode chamber contains 0.1 mol / L sodium sulfate electrolyte;

[0029] The cathode chamber contains the solution to be treated and is purged with oxygen;

[0030] The cathode uses the cathode electrode described above;

[0031] The reference electrode is Ag / AgCl, and the counter electrode is a platinum sheet;

[0032] The applied potential is -0.8V (vs. Ag / AgCl).

[0033] The present invention also discloses the application of the above-mentioned cathode electrode in sterilization or degradation of organic pollutants, wherein the organic pollutants are one or more of Rhodamine B, methyl orange or methylene blue.

[0034] The present invention also discloses a water treatment method, which uses the above-mentioned electrochemical catalytic system and operates at a potential of -0.8V for 10-35 minutes.

[0035] Compared with the prior art, the present invention has the following outstanding advantages:

[0036] 1. The cathode electrode (CoSO₄) involved in this invention X / HOPG) efficiently activates oxygen through cobalt and sulfur active sites to generate superoxide anions (·O2). - Reactive oxygen species such as hydrogen peroxide (H2O2) further react to generate (… 1 O2).

[0037] 2. The cathode electrode (CoSO₄) involved in this invention XCoO on the surface of / HOPG has excellent stability and adsorption capacity, ensuring its long-term high-efficiency performance in complex chemical and physical environments, and its excellent adsorption capacity can quickly capture and concentrate bacterial and dye pollutants, significantly improving the sterilization and degradation efficiency.

[0038] 3、The present application successfully prepared CoSO X / HOPG polyhedral electrochemical catalyst (cathode electrode) has significant advantages in electrochemical sterilization and dye pollutant degradation. CoSO X The unique structure of / HOPG enables it to stably and efficiently activate oxygen during electrocatalysis (principle as shown in Figure 1 ), generating highly selective 1 O2, thereby achieving rapid inactivation of E. coli and S. aureus and efficient degradation of dye pollutants such as rhodamine B, methyl orange, and methylene blue. The catalyst exhibits excellent performance in electrochemical sterilization, capable of completely inactivating high-concentration bacteria within 15 min, and the effectiveness of its sterilization mechanism is further confirmed by protein leakage and DNA degradation experimental results. CoSO X / HOPG also exhibits high efficiency and stability in dye pollutant degradation, with degradation rates remaining at a high level even after multiple cycles. This indicates that the CoSO X / HOPG catalyst (cathode electrode) developed by the present application has broad application prospects in the field of water treatment. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 CoSO X / HOPG electrochemical catalyst for electrochemical sterilization and dye pollutant degradation;

[0040] Figure 2 CoSO X / HOPG electrochemical catalyst prepared in Example 1 of the present application;

[0041] Figure 3 CoSO X / HOPG electrochemical catalyst prepared in Example 1 of the present application;

[0042] Figure 4 CoSO X / HOPG electrochemical catalyst prepared in Example 1 of the present application;

[0043] Figure 5 For the embodiments 2 CoSO X EPR spectra of different active oxygen species of / HOPG electrochemical catalysts;

[0044] Figure 6 For the embodiments 2 CoSO X Electrochemical production of / HOPG electrochemical catalysts 1 Mechanism study of O2. (A) EPR spectra of O2 and Ar conditions; 1 EPR spectra of O2; (B) EPR spectra under different scavenger conditions;

[0045] Figure 7 For the embodiments 3 CoSO X Colony inactivation of E. coli and S. aureus cultures under / HOPG electrochemical catalyst system (samples were taken at different reaction intervals);

[0046] Figure 8 For the embodiments 3 CoSO X (A) Polyhedral CoSO X Inactivation rate of E. coli in / HOPG catalyst system; (B) Polyhedral CoSO X Inactivation rate of E. coli in / HOPG catalyst system. Polyhedral CoSO X Effect of E. coli inactivation rate in / HOPG catalyst system, (C) Histidine masking 1 O2, (D) Catalase masking H2O2, (E) Methanol masking ·OH, (F) Superoxide dismutase masking ·O2 - ;

[0047] Figure 9 For the embodiments 3 CoSO X Electrochemical sterilization of E. coli in / HOPG electrochemical catalyst system. (A) Protein leakage, (B) DNA degradation, (C) Live and dead bacteria under different treatment times detected by flow cytometry;

[0048] Figure 10 For the embodiments 3 CoSO X Colony inactivation test of real hospital wastewater cultures in / HOPG electrochemical catalyst system (samples were taken at different reaction intervals);

[0049] Figure 11 For the embodiments 4 CoSO XThe feasibility of dye pollutant degradation under the HOPG electrochemical catalyst system is explored. The spectrograms of different concentrations of (A) RhB, (B) MO and (C) MB, the standard curves of the concentration and absorbance of (D) RhB, (E) MO and (F) MB, and the UV-visible absorption spectra of the solution during the degradation process of (G) 2 mg / L RhB, (H) 2 mg / L Mo and (I) 2 mg / L MB are shown in the drawings.

[0050] Figure 12 For the embodiments of the present application, CoSO X The degradation performance of dye pollutants under the HOPG electrochemical catalyst system is explored. The degradation efficiency of three different dyes, the kinetic fitting and the removal efficiency are shown in (A), (B) and (C), respectively. Taking RhB as an example, the degradation efficiency and the removal efficiency of the dye added with different quenching agents are shown in (D) and (E), respectively. The polyhedral CoSO X The inactivation efficiency of E. coli in the HOPG catalyst under different cycles. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0052] Name Explanation: In order to facilitate the understanding of the present application and maintain the consistency of the text, it is hereby explained that in the entire text of the present application (including the claims, the specification and the embodiments), the following terms have the same meaning:

[0053] "Cathode electrode", "cathode electrode for electrochemically activating O2" refers to the composite electrode prepared by any method of claims 1-5, taking an electrically conductive substrate (such as HOPG, sapphire, mica sheet, nickel foil) as the base, and the surface is deposited with cobalt oxysulfide (CoSO x ) containing oxygen.

[0054] "CoSOX / HOPG" specifically refers to the cathode electrode prepared by the method of the present application when taking highly oriented pyrolytic graphite (HOPG) as the electrically conductive substrate. It is a preferred and typical specific embodiment of the cathode electrode, and its name reflects the specific substrate material (HOPG) and the active material (cobalt oxysulfide containing oxygen, represented by the chemical formula CoSO x , which may be written as CoSOX in this document according to the layout or expression habit, where X represents the number of oxygen atoms, indicating that it is a non-stoichiometric oxygen-containing compound).

[0055] "Oxygen-containing cobalt sulfide polyhedral electrochemical catalyst" and "CoSO₄-X-polyhedral electrochemical catalyst" refer to oxygen-containing cobalt sulfide (CoSO₄) deposited on the surface of a conductive substrate, exhibiting a regular polyhedral morphology. x The material serves as the core active component of the cathode electrode.

[0056] "Oxygen-containing cobalt sulfide", "CoSO4" x "All refer to those with the general formula CoS" m O n Non-stoichiometric cobalt-sulfur-oxygen ternary compounds, whose structures contain characteristic or composite phases of cobalt sulfide (CoS) and cobalt oxide (CoO), are key materials for the electrocatalytic function of the cathode electrode of this invention.

[0057] Table 1 Raw Material List

[0058]

[0059]

[0060] Table 2 Instruments and Equipment

[0061]

[0062]

[0063] Example 1

[0064] This embodiment involves CoSO X Methods for preparing the substrate (cathode electrode), such as Figure 2 As shown, the tube furnace mentioned in this method is a low-pressure tube furnace, model Thermo HTF55322C, manufactured by Thermo Fisher Scientific, Inc., USA. The specific process steps include:

[0065] (1) First, clean the upper and lower surfaces of the substrate (including HOPG (1.2cm×1.2cm×0.1cm), sapphire (Φ5cm×0.43mm), mica sheet (1cm×1cm×0.02cm), and nickel foil (5cm×5cm×0.05cm), and observe it under a metallographic microscope to ensure that there are no impurities or contaminants on the upper and lower surfaces;

[0066] (2) In the order of placement, place the substrate 1-3 cm downstream of the center of the constant temperature zone of the tube furnace, place 2 g CoCl2 and 10 g sulfur powder in the corundum boat respectively, place it 1-3 cm upstream of the center of the constant temperature zone, place the corundum boat containing sulfur powder on the outside of the furnace chamber of the tube furnace, close to the furnace wall, and use a separate heating belt to control the heating time and temperature of the sulfur powder.

[0067] (3) Before the reaction formally begins, the air in the tube needs to be removed first. First, the tube furnace is pumped to the limit pressure and maintained for more than 10 min, then backfilled with Ar to ambient pressure. This cleaning cycle is repeated 3 times to ensure that the air in the tube furnace is completely removed;

[0068] (4) The mixed gas of Ar and H2 with a ratio of about 5:1 is injected into the system as the carrier gas during growth. When the pressure reaches 5000-20000 Pa, the sulfur powder is heated to completely melt and maintained for 10 min, so that the sulfur vapor is introduced into the growth area before heating CoCl2;

[0069] (5) The programmed temperature is raised, the tube furnace is heated to 850℃ within 35 min, and maintained at 850℃ for 5 min for CoSO X deposition;

[0070] (6) After the reaction, H2 is immediately turned off, the heating jacket is turned off to stop the supply of sulfur, the Ar flow is increased to remove impurities in the furnace, which protects the sample from damage;

[0071] (7) The vacuum pump and vacuum valve are turned off, the gas inlet device is removed, air is introduced, and the material is oxidized at 750-800℃ for 10-15 min. Then the heating system is turned off to wait for the cooling to end, and the sample can be taken out.

[0072] The materials grown on the four substrates were characterized by optical microscopy (OM). It can be seen from Figure 3 that the CoSO X material presents an ordered three-dimensional structure, the polygonal CoSO X particles have uniform size, uniform and regular geometric morphology, and are dispersed in space without obvious agglomeration or adhesion. It shows that the same process parameters (deposition temperature, oxidation step) can be used to obtain CoSO x polyhedrons with the same structure and performance on different substrates.

[0073] HOPG was used as the substrate for the following characterization and performance test. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Raman spectroscopy (Raman) were used to characterize the CoSO X on the HOPG substrate, and the results are shown in Figure 4 . Figure 4 A shows that the grown polygonal CoSO X has a polyhedral structure, and the particle size distribution is in the range of 1-2 μm. According to the calculation, there are about 4.6×10 6 CoSO X particles on a 1.2×1.2 cm HOPG substrate.Figure 4 EDS elemental analysis in B confirmed that Co and S atoms were well synthesized on HOPG, and CoSO X was uniformly distributed on the polygon. Figure 4 XPS analysis in C-4D showed that CoSO X had obvious signals of C, N, O, S and Co elements in the full spectrum, and the Co 2p spectrum could be divided into four peaks, corresponding to Co 2+ and Co 3+ , indicating that the synthesized polyhedral CoSO X had multiple valence states; in addition to the conventional 2p 2 / 3 and 2p 1 / 2 peaks, there was also an SO X peak, which was speculated to be formed by the sample contacting oxygen in the air during the transfer process. Figure 4 XRD measurement results in E showed that the synthesized polyhedral CoSO X / HOPG catalyst was not a single component, and its constituent components might be HOPG, Co3S4, Co9S4 and CoS2 stacked together in different forms. Figure 4 Raman spectrum analysis results in F-I showed that when the laser intensity was 1% and 10%, the Raman characteristic peaks of polyhedral CoSOX were very weak and almost not observed; when the laser intensity increased to 50%, obvious Co-S characteristic peaks appeared, corresponding to the Eg and Ag vibration modes of Co-S bond; when the laser intensity increased to 100%, the existence of C-O bond was also found, indicating that the sample was partially oxidized.

[0074] Example 2

[0075] This example relates to the study of the electrochemical performance of CoSO X / HOPG and the mechanism of electrochemical production of O2. The CoSO 1 / HOPG prepared in Example 1 was subjected to performance testing and mechanism study of O2 production under power supply conditions. First, the electrochemical performance of O2 production was studied, and the electron paramagnetic resonance (EPR) technique was used to detect the active oxygen species produced by the electrocatalytic reaction of the CoSO 1 / HOPG catalyst system at different times. 2,2,6,6-tetramethyl-4-piperidinol (TEMP) was used as the O2 trapping agent, and 5,5-dimethyl-1-pyrrole-N-oxide (DMPO) was used as the ·O2 X trapping agent. 1 1 1 X 1 - ​​​​​Catalase was used as a scavenger for H2O2, and methanol was used as a scavenger for ·OH. Their characteristic signals were detected by EPR technology.

[0076] Figure 5 The EPR results show that in CoSO X When performing electrocatalytic reactions in the / HOPG catalyst system, TEMP was detected as a trapping agent. 1 The characteristic signal of O2 (peak ratio of 1:1:1:1) indicates that CoSO X / HOPG catalyst can efficiently produce 1 O2. Meanwhile, when DMPO was used as a trapping agent, ·O2 was detected. - The characteristic peak was six times that of the target; when using Catalase and methanol as scavengers, characteristic peaks of H2O2 and ·OH were also detected, indicating that during the electrocatalytic process, H2O2, ·OH, and ·O2... - It is generated 1 Important precursors or intermediates of O2.

[0077] Then there's the electrochemical product. 1 The mechanism of O2 was studied, and the effects of O2 and Ar on CoSO were investigated. X EPR was measured in the / HOPG catalyst system to study the effect of O2 on... 1 The effect of O2 production. Superoxide dismutase (SOD) was added separately, along with O2... - (scavengers), L-histidine (L-His, 1 The study investigated the effects of O2 scavengers, methanol (a ·OH scavenger), and catalase (a H2O2 scavenger) on [the following substances / processes]. 1 The effect of O2 signal intensity was measured. CoSO₄ was determined under different pH conditions. X / HOPG catalyst production 1 O2 capacity, tested by adjusting pH value. 1 Changes in the O2 signal.

[0078] Figure 6 The results in A show 1 The signal generated by O2 can only be detected in an O2 atmosphere, but not in an Ar atmosphere, indicating that O2 is the generator. 1 The origin of O2. SOD, L-His, methanol, and Catalase have varying degrees of influence on the 1O2 signal intensity, with L-His acting as a scavenger. 1 The O2 signal could not be detected, indicating that 1 O2 plays a major role in this system; while the quenching of ·OH has a significant effect. 1The production of O2 was minimally affected, with only a slight change in the signal, suggesting that ·OH underwent a rapid kinetic transformation during the electrocatalytic production of 1O2. Figure 6 As shown in Figure B, with the increase of pH value... 1 The O2 signal increases accordingly, and the CoSO signal increases. X The catalyst exhibits broad pH tolerance, producing efficiently under both acidic and alkaline conditions. 1 O2. (This is a deduction / inference) 1 Possible pathways for O2 generation include the reduction of O2 to form O2. - , O2 - It reacts with H2O to produce ·OOH and ·OH, as well as ·OOH and ·O2. - The reaction produces HO4 - Ultimately transformed 1 O2.

[0079] Example 3

[0080] This embodiment involves CoSO X / HOPG (cathode electrode) in electrochemical production 1 An experiment was conducted to investigate the application of O2 in water disinfection. First, *E. coli* and *Staphylococcus aureus* were extracted from pure cultures of LB broth at -80°C and cultured separately overnight on LB agar plates. Then, single colonies were selected and inoculated into LB liquid medium, and cultured at 37°C and 190 rpm until the logarithmic growth phase. The bacterial solution was then diluted to the target concentration (1 × 10⁻⁶ for *E. coli*) using sterile electrolytes and a bacterial turbidimeter. 6 CFU / mL, Staphylococcus aureus 1×10 7 The original bacterial solution (CFU / mL) was diluted to the required concentration in a 60mL electrolytic cell system. The wastewater used in the test was taken from a hospital in Qingdao. Electrochemical sterilization experiments were then conducted in a two-chamber H-type electrolytic cell. 30mL of 0.1mol / L sodium sulfate solution was added to the anode chamber as the electrolyte, and 30mL of bacterial suspension was added to the cathode chamber while maintaining oxygenation. The applied potential was set to -0.8V vs. Ag / AgCl, and the treatment was carried out at room temperature (25±1℃). 0.5mL of the suspension was collected at different time points for plate colony counting. Furthermore, the treated bacteria were stained and analyzed. After treatment with propidium iodide (PI) and Syto 9 dye, the bacteria were collected, washed, and observed using flow cytometry. Simultaneously, logarithmic-phase *E. coli* were electrochemically sterilized. The supernatant was collected by centrifugation at 8000rpm for 5min, and protein leakage was determined using a BCA protein quantification kit. The bacterial precipitate was extracted using a TIANamp bacterial DNA kit to assess the degree of DNA degradation.

[0081] like Figure 7 As shown, CoSOX / HOPG catalyst exhibits excellent performance in electrochemical sterilization, and can completely inactivate 1×10⁻⁶ within 10 min. 6 CFU / mL of E. coli was completely inactivated within 15 min at a concentration of 1×10⁻⁶. 7 Staphylococcus aureus at CFU / mL. For example... Figure 8 As shown, the EPR masking agent experiment verified that... 1 The main role of O2 in electrochemical sterilization. When L-His (quencher) is added... 1 When H2O2 is added, the activity of E. coli is not affected by the electrochemical sterilization process; however, when catalase (quenching H2O2) and superoxide dismutase (quenching O2) are added, the activity of E. coli is not affected by the electrochemical sterilization process. - When ·OH is used as a free radical scavenger, bacterial inactivation is affected to varying degrees; however, when methanol (quenching ·OH) is added as a free radical scavenger, the bactericidal efficiency is almost unaffected, indicating that ·OH contributes little to the bactericidal process. Figure 9 As shown, with increasing electrochemical sterilization time, significant protein leakage occurred in E. coli cells. Figure 9 A) DNA degradation in damaged cells was assessed by gel electrophoresis. The DNA band intensity gradually decreased and disappeared with increasing treatment time. Figure 9 B). Figure 9 Flow cytometry results from C showed that the cell membranes of most bacteria were severely damaged within 15 minutes of sterilization, accompanied by significant protein leakage or DNA degradation. Figure 10 As shown, electrochemical sterilization treatment of actual hospital wastewater, although the bacterial inactivation effect is weakened due to the complexity of the wastewater components, still achieves a good electrochemical sterilization effect within 35 minutes.

[0082] Example 4

[0083] This embodiment involves CoSO X / HOPG (cathode electrode) in electrochemical production 1Experiments were conducted on the application of O2 in the degradation of dye pollutants. 20 mg L⁻¹ solutions of Rhodamine B (RhB), methyl orange (MO), and methylene blue (MB) dyes were prepared and diluted to a concentration of 2 mg / L. Electrocatalytic degradation tests were then performed in a dual-cell H-shaped electrolytic cell. 0.1 mol / L sodium sulfate was added to the electrolytic cell as the electrolyte, and the dye solution was placed in the cathode chamber, ensuring exposure to oxygen. All experiments were conducted at room temperature (25 ± 1 °C) with a potential set at -0.8 V vs. Ag / AgCl. During the degradation of dye pollutants, 300 μL of the treatment solution was taken from the dual-cell H-shaped electrolytic cell every 5 minutes within the time range of 0–30 min to prepare three parallel samples. The absorbance was measured using a microplate reader, and the dye concentration was determined based on the absorbance and a standard curve. The degradation rate of the dye at different time points was then calculated using a formula.

[0084] like Figure 11 As shown in AC, the spectrophotometers of RhB, MO, and MB at different concentrations indicate that these three dyes have maximum absorbance values ​​at their respective specific wavelengths: 553 nm for RhB, 464 nm for MO, and 663 nm for MB. Based on these maximum absorbance values ​​and their corresponding concentrations, standard curves for the different dyes were plotted. Figure 11 DF). For example Figure 11 As shown in GI, the polyhedron CoSO X During the degradation of RhB, MO, and MB by the / HOPG catalyst, the intensity of its characteristic adsorption peak gradually decreased over time, indicating that these three dyes were successfully degraded during the electrochemical oxidation process. Figure 12 As shown in AC, the polyhedron CoSO X The / HOPG catalyst achieved degradation efficiencies of 96%, 95%, and 98.3% for RhB, MO, and MB, respectively, and the degradation process followed a pseudo-first-order reaction kinetic model with reaction rate constants of 0.41 min⁻¹. -1 0.15min -1 0.12min -1 .like Figure 12 As shown in DE, the results were verified by EPR masking agent experiments. 1 The main role of O2 in the electrochemical degradation of dyes, when added 1 When O2 quencher L-His is used, the degradation efficiency of RhB is significantly reduced, while the removal efficiency is almost unaffected when ·OH quencher methanol is added. Figure 12 As shown in F, the polyhedron CoSO X The / HOPG catalyst exhibited good cyclicity and repeatability in repeated degradation experiments, with the degradation efficiency remaining at 96% after the 5th cycle.

[0085] In summary, through the systematic verification of the above embodiments, the oxygen-containing cobalt sulfide cathode electrode (especially CoSO₄) prepared by this invention has proven effective. X / HOPG) exhibits excellent comprehensive performance. Example 1 successfully obtained oxygen-containing cobalt sulfide materials with regular regular polyhedral morphology through one-step deposition on various conductive substrates. The materials exhibit uniform structure and good elemental distribution, confirming the universality and controllability of the preparation method. Example 2 further elucidates the core functional mechanism of this electrode, demonstrating its ability to efficiently and stably electroactivate oxygen at a mild potential (-0.8V), primarily generating highly selective singlet oxygen ( / HOPG) 1 The process involves the synergistic effect of multiple reactive oxygen species (O2) and exhibits good tolerance to changes in environmental pH. Example 3 verified the electrode's powerful bactericidal ability, which can completely inactivate high concentrations of standard strains of Escherichia coli and Staphylococcus aureus in a very short time (10-15 minutes) and effectively treat complex wastewater from actual hospitals; the bactericidal mechanism study confirmed... 1 O2 plays a dominant role, significantly disrupting bacterial cell structure and leading to protein leakage and DNA degradation. Example 4 further demonstrates the high efficiency and stability of this electrode in degrading typical organic dye pollutants (Rhodamine B, methyl orange, and methylene blue), achieving extremely high degradation rates (>95%) for all three dyes. The degradation process follows pseudo-first-order kinetics, and the electrode maintains excellent degradation performance even after multiple cycles. In summary, this cathode electrode combines high efficiency, stability, and broad applicability, demonstrating significant application potential in electrochemical water treatment sterilization and pollutant degradation.

[0086] The above are merely a few preferred embodiments of the present invention, described in a relatively specific and detailed manner, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A method of chemical vapor deposition of a cobalt oxysulfide cathode, characterized in that, The method comprises the following steps: (1) cleaning the surface of the conductive substrate to be free of impurities; (2) placing the substrate at 1-3 cm downstream of the center of the constant temperature zone of a tube furnace, placing CoCl2 and sulfur powder in corundum boats respectively, and placing the boats at 1-3 cm upstream of the center of the constant temperature zone, with the sulfur powder boat being tightly attached to the wall of the furnace and being controlled in temperature by an independent heating belt; (3) vacuumizing and keeping for a certain period of time, and then repeatedly replacing the air in the tube with Ar; (4) introducing a mixed carrier gas containing a reducing component, heating the sulfur powder to complete melting when the pressure reaches 5000-20000 Pa, and keeping for >10 min; (5) performing deposition of cobalt sulfide containing oxygen by programmed temperature rising to 800-850 ℃ and keeping; (6) stopping the supply of reducing gas and sulfur, and introducing an inert gas to remove impurities; (7) introducing an oxygen-containing gas to perform oxidation treatment, and the oxidation treatment is oxidation at 700-800 ℃ for 5-20 min, and the cathode electrode is obtained after cooling.

2. The method according to claim 1, wherein: in step (3), the air in the tube is removed by vacuumizing to an extreme pressure and keeping for >10 min, and then repeatedly backfilling with Ar to ambient pressure for at least 3 cycles.

3. The method according to claim 1, wherein: in step (4), the mixed carrier gas is a mixture of Ar and H2, and the volume ratio of Ar to H2 is (3-10):

1.

4. The method according to claim 1, wherein: in step (5), the programmed temperature rising is rising to 800-850 ℃ within 30-40 min, and the deposition time is 3-8 min.

5. The method according to claim 1, wherein: the conductive substrate is selected from one of HOPG, sapphire, mica sheet or nickel foil.

6. A cathode electrode for electrochemically activating O2, which is prepared by any one of the methods according to claims 1-5, and wherein: the composite structure contains an amorphous CoO layer formed in situ by oxidation.

7. The cathode electrode according to claim 6, comprising: a double-chamber H-type electrolytic cell; an anode chamber containing 0.1 mol / L sodium sulfate electrolyte; a cathode chamber containing a solution to be treated and being supplied with oxygen; Cobalt sulfide (CoSO x ) is distributed on the surface of the substrate in regular structure of regular polyhedron with particle size of 1-2 μm; the cathode electrode according to claim 6 or 7; a reference electrode being Ag / AgCl, and a counter electrode being a platinum sheet; The cathode electrode can efficiently and stably generate singlet oxygen at a potential of -0.8V (vs. Ag / AgCl). 1 O2).

8. An electrochemical catalysis system, characterized in that, an applied potential being -0.8 V (vs. Ag / AgCl). the organic pollutants are one or more of rhodamine B, methyl orange or methylene blue. the electrochemical catalytic system according to claim 8 is operated at a potential of -0.8 V for 10-35 min. ​ ​ ​ ​ 9. Use of the cathode electrode according to claim 6 or 7 for the disinfection or degradation of organic pollutants, characterized in that, ​ 10. A method of water treatment, characterized by, ​

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