Low-coordination platinum monatomic catalyst, synthesis method thereof and two-pole coupling electrochemical sterilization method based on low-coordination platinum monatomic catalyst

Abstract

The invention discloses a low-coordination platinum monatomic catalyst, a synthesis method thereof and a two-pole coupling electrochemical sterilization method based on the low-coordination platinum monatomic catalyst. The low-coordination platinum monatomic catalyst has a bifunctional electrocatalytic property and can be used for constructing an electrochemical sterilization system. The catalyst is prepared by loading platinum single atoms on carbon nanotubes, and the platinum single atom catalyst has good conductivity, shows a bifunctional electro-catalysis characteristic, can catalyze chloride ions to oxidize to generate chlorine (Cl2) and catalyze oxygen to reduce to generate hydrogen peroxide (H2O2) at the same time. The platinum monatomic catalyst is modified at the positive electrode and the negative electrode respectively, Cl2 and H2O2 are generated at the same time under the driving of external voltage, and Cl2 and H2O2 can further react in a solution to generate singlet oxygen with strong oxidizing property, so that a multi-active-substance synergistic sterilization system is constructed, and efficient electrochemical sterilization application is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of environmental engineering, and in particular relates to a low-coordination platinum single-atom catalyst, a synthesis method thereof, and a bipolar coupled electrochemical sterilization method based on the catalyst. Background Art

[0002] In recent years, the problem of microbial contamination in water bodies has become increasingly prominent, especially in the field of drinking water and public health, and the removal of pathogenic microorganisms in water has become a research hotspot. Pathogenic microorganisms in water bodies, including bacteria, viruses, fungi and algae, not only affect water quality, but may also cause health risks.

[0003] Among the existing water treatment technologies, the dosage of disinfectants in traditional chlorination disinfection is difficult to control accurately and is prone to produce harmful byproducts; ultraviolet disinfection is easily affected by the transparency of the water body; and ozone disinfection has technical problems such as high equipment investment and operating costs. In recent years, electrochemical sterilization technology has gradually become a potential technology that can replace traditional disinfection methods due to its high efficiency, wide adaptability and low energy consumption. Electrochemical sterilization technology produces oxidizing substances such as chlorine, hydrogen peroxide, and hydroxyl free radicals through electrolysis reactions, which can inactivate pathogenic microorganisms in water bodies.

[0004] Existing electrochemical sterilization methods mainly use precious metal electrodes or metal oxide electrodes to produce active oxygen and active chlorine substances through single electrode or monopolar electrolysis. However, these methods have problems such as low catalyst utilization, high cost, limited sterilization effect of single active substances, and difficulty in controlling the synergistic production of multiple active substances. In addition, existing electrochemical sterilization systems often require different catalysts to be used at the cathode and anode to achieve different electrochemical reactions, which not only increases the complexity of the system, but also increases the cost of preparation and use.

[0005] Therefore, developing a single catalyst with bifunctional electrocatalytic properties to achieve the synergistic bactericidal effect of multiple active substances has important theoretical value and application prospects. Summary of the invention

[0006] The purpose of the present invention is to provide a bipolar coupled electrochemical sterilization method based on a bifunctional low-coordinated platinum single-atom catalyst. The method achieves the synergistic production of chlorine and hydrogen peroxide by simultaneously modifying the low-coordinated platinum single-atom catalyst at both the cathode and cathode, thereby generating singlet oxygen ( 1 O2) to achieve efficient sterilization.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a low-coordination platinum single-atom catalyst.

[0009] The low-coordination platinum single-atom catalyst comprises a carbon-based carrier and metal platinum, wherein the metal platinum is loaded on the surface of the carbon-based carrier in the form of a single-atom site.

[0010] Furthermore, the carbon-based carrier includes but is not limited to carbon nanotubes, graphene, activated carbon, etc.

[0011] Furthermore, the loading amount of platinum on the low-coordinated platinum single-atom catalyst is 0.2 to 1.0 wt %;

[0012] In some embodiments of the present invention, the average diameter of the low-coordinated platinum single atom catalyst is 10 nm to 20 nm, and the thickness of the carbon nanotube is no greater than 20 nm. Thus, a single platinum atom can be loaded on the surface of the carbon nanotube.

[0013] In some embodiments of the present invention, the oxygen-carbon ratio of the low-coordinated platinum single-atom catalyst is not greater than 0.005, thereby achieving efficient electron transport and highly active electrocatalytic performance.

[0014] In some embodiments of the present invention, the nitrogen-carbon ratio of the low-coordinated platinum single-atom catalyst is not greater than 0.005, thereby achieving efficient electron transport and highly active electrocatalytic performance.

[0015] In a second aspect, the present invention provides a method for preparing the low-coordination platinum single-atom catalyst described in the first aspect.

[0016] The method for preparing the low-coordination platinum single-atom catalyst provided by the present invention comprises the following steps:

[0017] (1) adding a platinum complex (Pt-Salen) to an organic solution and stirring the solution sufficiently to obtain a dissolved transparent solution;

[0018] (2) adding the carbon-based carrier to the solution in step (1), and stirring for a certain period of time to obtain a mixed dispersion;

[0019] (3) centrifuging, washing, and drying the mixed dispersion in step (2) to obtain a solid powder;

[0020] (4) Under an argon atmosphere, the solid powder in step (3) is pyrolyzed at high temperature to obtain a low-coordinated platinum single atom catalyst.

[0021] In the above method, the organic solution is selected from at least one of the following: N,N-dimethylformamide, chloroform, n-hexane, tetrahydrofuran, etc.;

[0022] In the above method, the carbon-based carrier is carbon nanotubes, and the mass ratio of the carbon nanotubes to the platinum complex (Pt-Salen) is 100:(1-10), specifically 100:1; 100:2; 100:4; 100:8; 100:10, etc.

[0023] In the above method, the high temperature pyrolysis condition is to heat continuously for 2 hours at 600-800°C in an argon atmosphere.

[0024] In a third aspect, the present invention provides the application of the low-coordination platinum single-atom catalyst described in the first aspect in bipolar coupled electrochemical sterilization.

[0025] Through the above technical scheme, the low-coordinated platinum single-atom catalyst provided by the present invention includes a carbon-based material having a single platinum metal site loaded on a carbon nanotube, wherein the platinum single atom is uniformly loaded on the surface of the carbon nanotube. Due to the strong adsorption between the Pt-Salen complex and the carbon nanotube, the Pt-Salen complex can be uniformly distributed on the surface of the carbon nanotube, so that the metal active center of the catalyst can be uniformly dispersed on the surface of the carrier after pyrolysis.

[0026] The inventors have discovered that low-coordinated platinum single-atom catalysts can produce a certain concentration of hydrogen peroxide through electrochemical reduction in an electrolyte containing oxygen. At the same time, through research, it was found that low-coordinated platinum single-atom catalysts can generate chlorine through electrochemical oxidation in an electrolyte containing chloride ions. Therefore, low-coordinated platinum single-atom catalysts can be used as bifunctional cathode and anode catalysts to produce hydrogen peroxide and chlorine respectively. And the inventors further discovered that the two products can further generate highly active singlet oxygen. Therefore, low-coordinated platinum single-atom catalysts can be used as electrocatalysts for active species to achieve efficient sterilization by bipolar coupled electrochemistry.

[0027] In a fourth aspect, the present invention provides a method for bipolar coupled electrochemical sterilization based on the low-coordination platinum single atom catalyst described in the first aspect.

[0028] The bipolar coupled electrochemical sterilization method provided by the present invention comprises the following steps:

[0029] (1) mixing a buffered electrolyte solution and a bacterial culture medium solution and storing the mixture at a low temperature to obtain a buffered electrolyte-bacterial culture medium mixture;

[0030] (2) mixing the buffered electrolyte and bacterial culture medium mixture with sodium chloride and storing the mixture at low temperature to obtain a buffered electrolyte for sterilization;

[0031] (3) preparing a low-coordination platinum single-atom catalyst modified electrode by preparing the low-coordination platinum single-atom catalyst;

[0032] (4) inserting the low-coordination platinum single-atom catalyst modified electrode as the cathode and anode respectively into the sterilization buffer electrolyte described in step (2), and performing electrolysis for a specified time to obtain a sterilized buffer electrolyte.

[0033] Furthermore, the method further comprises:

[0034] (5) Incubate the bacteria in the sterilized buffered electrolyte on a solid culture medium to obtain the number of colonies after sterilization.

[0035] In some embodiments of the present invention, in step (1), the concentration of the bacteria in the buffered electrolyte-bacteria culture medium mixture is not less than 10^5 CFU / mL;

[0036] In some embodiments of the present invention, in step (1), the concentration of the bacteria in the buffered electrolyte-bacteria culture medium mixture is 10^6 CFU / mL to 10^9 CFU / mL;

[0037] In some embodiments of the present invention, in step (1), the buffered electrolyte-bacteria culture medium mixture comprises at least one of a phosphate buffered saline solution and a bicarbonate buffer solution;

[0038] In some embodiments of the present invention, in step (1), the volume ratio of the buffered electrolyte to the bacterial culture medium solution is no greater than 10:1;

[0039] In some embodiments of the present invention, in step (1), the cryopreservation temperature does not exceed 4°C.

[0040] In some embodiments of the present invention, in step (2), the sodium chloride in the sterilization buffer electrolyte is 0.12 mol / L to 1.0 mol / L.

[0041] In some embodiments of the present invention, in step (2), the cryopreservation temperature does not exceed 4°C.

[0042] In some embodiments of the present invention, in step (3), the total volume of the dispersion is between 0.5 mL and 1 mL;

[0043] In some embodiments of the present invention, in step (3), the concentration of the low-coordinated platinum single-atom catalyst in the dispersion is 0.5 mg / mL to 10 mg / mL;

[0044] In some embodiments of the present invention, in step (3), the solvent of the dispersion includes ethanol, deionized water, At least one of D-521 and isopropyl alcohol;

[0045] In some embodiments of the present invention, in step (3), the dispersion needs to be treated under ultrasonic conditions for 0.5 h to 2 h;

[0046] In some embodiments of the present invention, in step (3), the modification amount of the low-coordinated platinum single-atom catalyst on the modified electrode is 3 mg / cm 2 ~30mg / cm 2 ;

[0047] In some embodiments of the present invention, in step (3), the modified electrode is a glassy carbon electrode;

[0048] In some embodiments of the present invention, in step (3), the electrode diameter of the modified electrode is 3 mm to 5 mm;

[0049] In some embodiments of the present invention, in step (3), the number of the modified electrodes is not less than 2.

[0050] In some embodiments of the present invention, in step (4), the amount of the sterilization buffer electrolyte added is 2 mL to 10 mL;

[0051] In some embodiments of the present invention, in step (4), the voltage of the electrolysis is 1.0V to 1.8V;

[0052] In some embodiments of the present invention, in step (4), the time of the electrolysis is 0.05h to 1h.

[0053] In some embodiments of the present invention, in step (5), the inoculation amount of the sterilized buffered electrolyte on the solid culture medium is 1 μL to 20 μL;

[0054] In some embodiments of the present invention, in step (5), the solid culture medium may be a circular solid culture medium with a diameter of 10 cm and a thickness of 0.2 cm to 1 cm.

[0055] In some embodiments of the present invention, in step (5), the bacterial incubation temperature is 36°C;

[0056] In some embodiments of the present invention, in step (5), the bacterial incubation time is 6 h to 12 h;

[0057] In some embodiments of the present invention, in step (5), the solid culture medium comprises agar, sodium chloride, peptone, yeast extract and sodium hydroxide.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] The low-coordination platinum single-atom catalyst provided by the present invention has a bifunctional electrocatalytic performance. It can catalyze the oxidation of chloride ions to produce chlorine (Cl2), and at the same time catalyze the reduction of oxygen to produce hydrogen peroxide (H2O2). By modifying the platinum single-atom catalyst at the positive and negative poles respectively, Cl2 and H2O2 are simultaneously produced under the drive of an applied voltage. Cl2 and H2O2 can further react in the solution to produce highly oxidizing singlet oxygen, thereby constructing a sterilization system with multiple active substances in coordination, and realizing efficient electrochemical sterilization applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0061] Figure 1 This is a transmission electron microscope image of the low-coordinated single-atom catalyst obtained in Example 1 of the present invention;

[0062] Figure 2 This is a spherical aberration-corrected transmission electron micrograph of the low-coordinated single-atom catalyst obtained in Example 1 of the present invention;

[0063] Figure 3 This is a graph showing the electrochemical test results of using the low-coordinated single-atom catalyst of Example 2 of the present invention as a cathode material to produce hydrogen peroxide;

[0064] Figure 4 This is a graph showing the electrochemical test results of the low-coordinated single-atom catalyst used as an anode material to produce chlorine and a control group according to Example 2 of the present invention;

[0065] Figure 5 It is a test result diagram of singlet oxygen produced by the low-coordinated single-atom catalyst of Example 2 of the present invention as anode and cathode materials and Comparative Example 1, Comparative Example 2 and a control group;

[0066] Figure 6 is a scanning electron microscope image of Escherichia coli of Example 2 of the present invention;

[0067] Figure 7 is a scanning electron microscope image of the Escherichia coli of the control group of the present invention;

[0068] Figure 8 It is a statistical result diagram of the bactericidal effects of Example 2 of the present invention, Comparative Examples 1-2 and the control group. DETAILED DESCRIPTION

[0069] The embodiments of the present invention are described in detail below, which are intended to explain the present invention but should not be construed as limiting the present invention.

[0070] In one aspect of the present invention, a bipolar coupled electrochemical sterilization method based on a low-coordination platinum single atom catalyst is proposed.

[0071] The inventors have discovered that low-coordinated platinum single-atom catalysts have bifunctional electrocatalytic properties, including the ability to produce a certain concentration of hydrogen peroxide by electrochemical reduction in an electrolyte containing oxygen. It was also discovered that low-coordinated platinum single-atom catalysts can generate chlorine by electrochemical oxidation in an electrolyte containing chloride ions. Thus, low-coordinated platinum single-atom catalysts can be used as bifunctional cathode and anode catalysts to produce hydrogen peroxide and chlorine, respectively. And the two products can further generate highly active singlet oxygen. Therefore, low-coordinated platinum single-atom catalysts can be used as electrocatalysts for active species to achieve bipolar coupled electrochemical efficient sterilization applications.

[0072] According to an embodiment of the present invention, the average diameter of the low-coordinated platinum single-atom catalyst is 10nm to 20nm. The inventors found that when using carbon nanotubes of larger sizes, due to the adsorption of too much Pt-Salen complex, metal platinum is prone to agglomeration during preparation, affecting the electrocatalytic activity and the selectivity of hydrogen peroxide generation. Therefore, the present application uses carbon nanotubes with an average diameter of 10nm to 20nm as carriers to achieve the dual function of low-coordinated platinum single-atom catalysts to produce hydrogen peroxide and chlorine, and further generate singlet oxygen, thereby realizing the application of high-activity electrochemical sterilization.

[0073] According to an embodiment of the present invention, the oxygen-carbon ratio of a low-coordinated platinum single-atom catalyst is not greater than 0.005. The inventors have found that when a low-coordinated platinum single-atom catalyst with an oxygen-carbon ratio greater than 0.005 is used, the presence of too much oxygen will affect the electrocatalytic activity and the selectivity of hydrogen peroxide generation. Therefore, the present application uses a low-coordinated platinum single-atom catalyst with an oxygen-carbon ratio of no more than 0.005 to achieve the dual function of the low-coordinated platinum single-atom catalyst to produce hydrogen peroxide and chlorine, and further generate singlet oxygen, thereby realizing the application of high-activity electrochemical sterilization.

[0074] According to an embodiment of the present invention, the nitrogen-carbon ratio of the low-coordinated platinum single-atom catalyst is not greater than 0.005. The inventors have found that when a low-coordinated platinum single-atom catalyst with a nitrogen-carbon ratio greater than 0.005 is used, the presence of too much nitrogen will affect the electrocatalytic activity and the selectivity of hydrogen peroxide generation. Therefore, the present application uses a low-coordinated platinum single-atom catalyst with a nitrogen-carbon ratio of no more than 0.005 to achieve the dual function of the low-coordinated platinum single-atom catalyst to produce hydrogen peroxide and chlorine, and further generate singlet oxygen, thereby realizing the application of high-activity electrochemical sterilization.

[0075] According to an embodiment of the present invention, the method of using a low-coordinated platinum single-atom catalyst for bipolar coupled electrochemical sterilization includes:

[0076] S100: mixing the buffered electrolyte and the bacterial culture medium solution and storing them at low temperature to obtain a buffered electrolyte and bacterial culture medium mixed solution;

[0077] In this step, a buffered electrolyte having an oxygen concentration of not less than 9 mg / L and a phosphate concentration of not less than 0.01 moL / L is mixed with a culture solution having an Escherichia coli concentration of 2x10^6 CFU / mL to 2x10^9 CFU / mL, thereby obtaining a buffered electrolyte-bacteria culture medium mixture. Furthermore, the oxygen concentration in the buffered electrolyte-bacteria culture medium mixture is not less than 9 mg / L, so that the low-coordination platinum single-atom catalyst can electrocatalyze oxygen to generate hydrogen peroxide. The concentration of Escherichia coli is 10^6 CFU / mL to 10^9 CFU / mL. It should be noted that the Escherichia coli culture solution and the buffer solution are conventional reagents in the field, and those skilled in the art can select the concentration according to actual conditions. For example, the concentration of Escherichia coli can be 10^5 CFU / mL to 10^10 CFU / mL, and the concentration of the buffer solution can be 0.01 moL / L to 0.1 moL / L; the buffer solution includes at least one of a phosphate buffered saline solution and a bicarbonate buffer solution;

[0078] S200: mixing the buffered electrolyte and bacterial culture medium mixture with sodium chloride and storing the mixture at low temperature to obtain a buffered electrolyte for sterilization;

[0079] In this step, a certain amount of sodium chloride solid is added to the buffered electrolyte bacterial culture medium mixture obtained in S100, so that the chloride ion concentration in the buffered electrolyte bacterial culture medium mixture is 0.14 mol / L to 0.24 mol / L, so that the low-coordinated platinum single atom catalyst electrocatalyzes chloride ions to generate chlorine gas.

[0080] S300: preparing the low-coordination platinum single-atom catalyst into a catalyst dispersion to obtain a modified electrode of the low-coordination platinum single-atom catalyst;

[0081] In this step, 2 mg to 10 mg of low-coordinated platinum single-atom catalyst is dispersed in at least one solvent including ethanol, deionized water, nafion-521 and isopropanol to obtain a low-coordinated platinum single-atom catalyst dispersion. Further, the catalyst dispersion is ultrasonically treated for 0.5 h to 2 h to obtain a uniform dispersion of low-coordinated platinum single-atom catalyst with a total volume of 0.5 mL to 1 mL. Further, the dispersion is modified on the surface of a glassy carbon electrode with a diameter of 3 mm to 5 mm, and the mass of the low-coordinated platinum single-atom catalyst on the electrode is 0.02 mg to 0.1 mg, thereby obtaining a modified electrode of a low-coordinated platinum single-atom catalyst. It should be noted that the number of modified electrodes is not less than 2; the reagents in the dispersion are conventional reagents in the art, and those skilled in the art can select according to actual conditions, for example, the dispersion includes at least one of ethanol and isopropanol.

[0082] S400: inserting the modified electrode of the low-coordinated platinum single-atom catalyst as a cathode and an anode into the bactericidal buffer electrolyte, respectively, so as to conduct electrolysis for a certain period of time;

[0083] In this step, two modified electrodes of low-coordinated platinum single-atom catalyst obtained in S300 are inserted into 1 mL to 20 mL of sterilized buffered electrolyte obtained in S200, serving as cathode and anode, respectively. Furthermore, an electrolysis voltage of 1.0 V to 1.8 V is applied between the two electrodes, and the electrolysis time is 0.1 h to 1.0 h. After electrolysis, a sterilized buffered electrolyte is obtained.

[0084] S500: incubating bacteria with the sterilized buffered electrolyte on a solid culture medium to obtain the number of sterilized colonies;

[0085] In this step, 10 μL to 20 μL of the sterilized buffered electrolyte obtained in S400 is inoculated onto a solid culture medium for incubation, wherein the incubation time is 6 h to 12 h; and the incubation temperature is 36°C. Further, the colonies on the solid culture medium after incubation are counted and statistically analyzed. It should be noted that the solid culture medium includes agar, sodium chloride, peptone, yeast extract, beef extract, and sodium hydroxide, for example, includes at least one of beef extract and peptone;

[0086] Low-coordinated platinum single-atom catalysts can be used as bifunctional cathode and anode catalysts to produce hydrogen peroxide and chlorine respectively. And the two products can further generate highly active singlet oxygen. Therefore, low-coordinated platinum single-atom catalysts can be used as electrocatalysts of active species to achieve bipolar coupled electrochemical efficient sterilization applications.

[0087] The present invention is described below with reference to specific embodiments. It should be noted that these embodiments are merely illustrative and do not limit the present invention in any way.

[0088] Example 1

[0089] 10 mg of platinum complex (Pt-Salen) was added to 20 mL of N,N-dimethylformamide and stirred thoroughly to obtain a dissolved transparent solution; 100 mg of multi-walled carbon nanotubes with a diameter of 10-20 nm were added to the solution and stirred thoroughly for a certain period of time to obtain a mixed dispersion; further, the mixed dispersion was centrifuged, washed, and dried to obtain a solid powder; under argon protection, the solid powder was pyrolyzed at 700° C. for 2 h to obtain a low-coordinated platinum single-atom catalyst with a platinum loading of 0.61 wt% as measured by an inductively coupled plasma optical emission spectrometer (ICP-OES).

[0090] The low-coordination platinum single-atom catalyst prepared in this embodiment is as follows Figure 1 and Figure 2 As shown, from Figure 1 and Figure 2 It can be seen that the main carrier of the low-coordinated platinum single-atom catalyst is carbon nanotubes with a diameter of 10nm to 20nm, and the single-atom dispersion state of platinum can be observed through a spherical aberration electron microscope.

[0091] Example 2

[0092] (1) Mix 0.01 mol / L phosphate buffer solution with E. coli culture medium to prepare a mixed solution of buffered electrolyte and bacterial culture medium with an E. coli concentration in the range of 10^5 CFU / mL to 10^10 CFU / mL. Take 2 mL as the electrolyte, add 14 mg of sodium chloride, stir thoroughly to dissolve, and store at 4°C for later use.

[0093] (2) 10 mg of the low-coordinated platinum single atom catalyst prepared in Example 1 was dispersed in 1 mL of a mixed solution, wherein the mixed solution mainly included 720 μL of deionized water, 220 μL of isopropanol and 60 μL of D-521. Furthermore, a uniformly dispersed low-coordinated platinum single-atom catalyst dispersion was obtained by ultrasonication for 2 h. The dispersion obtained after ultrasonication was modified on two glassy carbon electrodes with a diameter of 3 mm, and the modification amount of the low-coordinated Pt single-atom catalyst was 15 mg / cm 2 Furthermore, a low-coordinated platinum single-atom catalyst modified electrode was obtained after drying.

[0094] (3) Insert the two low-coordinated platinum single-atom catalyst modified electrodes obtained in step (2) into the 2 mL electrolyte in step (1). Further, a voltage of 1.4 V is applied to the two low-coordinated platinum single-atom catalyst modified electrodes for 5 min. Finally, the electrolyte obtained after electrolysis is stored at 4°C.

[0095] (4) 10 μL of the electrolyzed solution obtained in step (3) was inoculated onto a circular solid culture medium with a diameter of 10 cm and a thickness of 0.2 cm to 1 cm and incubated for 12 h at a temperature of 36° C. Further, the colonies on the solid culture medium after incubation were counted.

[0096] Example 2 Step (3) Preparation of low-coordination platinum single-atom catalyst modified electrode with dual functional properties of producing hydrogen peroxide and chlorine Figure 3 and Figure 4 As shown, from Figure 3 It can be seen that the linear scan results of the electrochemical rotating ring disk electrode show that the oxygen in the electrolyte is electro-reduced by the low-coordinated platinum single atom catalyst to generate hydrogen peroxide. Figure 4 It can be seen that the low-coordinated platinum single atom catalyst can electro-oxidize chloride ions to produce chlorine gas.

[0097] Example 2 Step (3) Preparation of low-coordination platinum single-atom catalyst modified electrode During the production of hydrogen peroxide and chlorine, singlet oxygen is further generated. Figure 5 It can be seen that the free radical detection results show that hydrogen peroxide and chlorine can be produced through the electrolysis process in an electrolyte containing oxygen and chloride ions, which further generates singlet oxygen.

[0098] In step (3) of Example 2, almost all the Escherichia coli in the electrolyte after electrolysis were killed. Figure 6 It can be seen that the scanning electron microscopy results show that the structure of E. coli after electrolysis is severely damaged, the bacterial membrane collapses over a large area, and the bacterial morphology disappears.

[0099] Comparative Example 1

[0100] (1) Mix 0.01 mol / L phosphate buffer solution with E. coli culture medium to prepare a mixed solution of buffered electrolyte and bacterial culture medium with an E. coli concentration in the range of 10^6 CFU / mL to 10^9 CFU / mL. Take 2 mL as the electrolyte and store it at 4°C for later use.

[0101] (2) 10 mg of low-coordinated platinum single-atom catalyst was dispersed in 1 mL of a mixed solution, wherein the mixed solution mainly included 720 μL of deionized water, 220 μL of isopropanol and 60 μL of nafion-521. Further, ultrasonic treatment was performed for 2 h to obtain a uniformly dispersed dispersion of low-coordinated platinum single-atom catalyst. The dispersion obtained after ultrasonic treatment was modified on two glassy carbon electrodes with a diameter of 3 mm. Further, a low-coordinated platinum single-atom catalyst modified electrode was obtained by drying.

[0102] (3) Insert the two low-coordinated platinum single-atom catalyst modified electrodes obtained in step (2) into the 2 mL electrolyte in step (1). Further, a voltage of 1.4 V is applied to the two low-coordinated platinum single-atom catalyst modified electrodes for 5 min. Finally, the electrolyte obtained after electrolysis is stored at 4°C.

[0103] (4) 10 μL of the electrolyte obtained in step (3) was inoculated on a solid culture medium and incubated for 12 h at a temperature of 36° C. Further, the colonies on the solid culture medium after incubation were counted. Further, the statistical results are as follows: Figure 8 As shown, the reduction in colony number was less than 1 order of magnitude.

[0104] Comparative Example 2

[0105] (1) Mix 0.01 mol / L phosphate buffer solution with E. coli culture solution to prepare a mixed solution of buffered electrolyte and bacterial culture medium with an E. coli concentration in the range of 10^6 CFU / mL to 10^9 CFU / mL. Take 2 mL as the electrolyte, add 14 mg of sodium chloride, stir well to dissolve, and further, pass argon for 15 minutes to remove oxygen components in the electrolyte, and store at 4°C for use.

[0106] (2) 10 mg of low-coordinated platinum single atom catalyst was dispersed in 1 mL of a mixed solution, wherein the mixed solution mainly consisted of 720 μL of deionized water, 220 μL of isopropanol and 60 μL of D-521. Further, a uniformly dispersed low-coordinated platinum single atom catalyst dispersion was obtained by ultrasonication for 2 hours. The dispersion obtained after ultrasonication was modified on two glassy carbon electrodes with a diameter of 3 mm. Further, a low-coordinated platinum single atom catalyst modified electrode was obtained by drying.

[0107] (3) Insert the two low-coordinated platinum single-atom catalyst modified electrodes obtained in step (2) into the 2 mL electrolyte in step (1). Further, a voltage of 1.4 V is applied to the two low-coordinated platinum single-atom catalyst modified electrodes for 5 min. Finally, the electrolyte obtained after electrolysis is stored at 4°C.

[0108] (4) 10 μL of the electrolyte obtained in step (3) was inoculated on a solid culture medium and incubated for 12 h at a temperature of 36° C. Further, the colonies on the solid culture medium after incubation were counted. Further, the statistical results are as follows: Figure 8 As shown, the reduction in colony number was less than 4 orders of magnitude.

[0109] Control group

[0110] (1) 0.01 mol / L phosphate buffer solution was mixed with E. coli culture solution to prepare a mixed solution of buffered electrolyte and bacterial culture medium with an E. coli concentration in the range of 10^6 CFU / mL to 10^9 CFU / mL. Further, argon gas was introduced for 15 min to remove the oxygen component in the electrolyte, 2 mL was taken as the electrolyte, stirred and dissolved thoroughly, and stored at 4°C for later use.

[0111] (2) 10 mg of low-coordinated platinum single atom catalyst was dispersed in 1 mL of a mixed solution, wherein the mixed solution mainly consisted of 720 μL of deionized water, 220 μL of isopropanol and 60 μL of D-521. Further, a uniformly dispersed low-coordinated platinum single atom catalyst dispersion was obtained by ultrasonication for 2 hours. The dispersion obtained after ultrasonication was modified on two glassy carbon electrodes with a diameter of 3 mm. Further, a low-coordinated platinum single atom catalyst modified electrode was obtained by drying.

[0112] (3) Insert the two low-coordination platinum single-atom catalyst modified electrodes obtained in step (2) into the 2 mL electrolyte in step (1). Further, the duration of no power supply is 5 min. Finally, the obtained electrolyte is stored at 4°C.

[0113] (4) 10 μL of the electrolyzed solution obtained in step (3) was inoculated on a solid culture medium and incubated for 12 h at a temperature of 36° C. Further, the colonies on the solid culture medium after incubation were counted.

[0114] The E. coli in the electrolyte after electrolysis in step (3) is basically alive. Figure 7 It can be seen that the scanning electron microscopy results show that the structure of E. coli after electrolysis is intact, the bacterial membrane has not collapsed, and the bacterial morphology is intact.

[0115] The statistical results of electrochemical sterilization of the control group, Example 2 and Comparative Examples 1-2 are shown in Figure 8 .from Figure 8 It can be seen that there is no significant change in the number of colonies in Comparative Examples 1-2 and the control group after incubation for 12 hours. This indicates that there is no significant bactericidal ability directly in the atmosphere of low concentration hydrogen peroxide and chlorine. The colony statistics in Example 2 are significantly reduced by 8 orders of magnitude, indicating that the bactericidal efficiency of bipolar coupling to produce hydrogen peroxide and chlorine is significantly improved.

[0116] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0117] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A low-coordination platinum single-atom catalyst, comprising a carbon-based carrier and metallic platinum, wherein the metallic platinum is loaded on the surface of the carbon-based carrier in the form of a single-atom site.

2. The low-coordination platinum single-atom catalyst according to claim 1, characterized in that: The carbon-based carrier includes but is not limited to carbon nanotubes, graphene or activated carbon; and / or, the loading amount of platinum on the low-coordinated platinum single-atom catalyst is 0.2 to 1.0 wt %; And / or, the average diameter of the low-coordinated platinum single-atom catalyst is 10-20 nm; and / or, the oxygen-to-carbon ratio of the low-coordination platinum single-atom catalyst is not greater than 0.005; And / or, the nitrogen-to-carbon ratio of the low-coordination platinum single-atom catalyst is not greater than 0.

005.

3. The method for preparing the low-coordination platinum single-atom catalyst according to claim 1 or 2, comprising the following steps: (1) adding a platinum complex Pt-Salen to an organic solution and stirring the solution sufficiently to obtain a dissolved transparent solution; (2) adding the carbon-based carrier to the solution in step (1), and stirring for a certain period of time to obtain a mixed dispersion; (3) centrifuging, washing, and drying the mixed dispersion in step (2) to obtain a solid powder; (4) Under an argon atmosphere, the solid powder in step (3) is pyrolyzed at high temperature to obtain the low-coordinated platinum single atom catalyst.

4. Use of the low-coordination platinum single-atom catalyst according to claim 1 or 2 or the low-coordination platinum single-atom catalyst prepared by the method according to claim 3 as a bifunctional electrocatalyst in bipolar coupled electrochemical sterilization.

5. A method for bipolar coupled electrochemical sterilization based on the low-coordination platinum single-atom catalyst according to claim 1 or 2 or the low-coordination platinum single-atom catalyst prepared by the method according to claim 3, comprising the following steps: (1) mixing a buffered electrolyte solution and a bacterial culture medium solution and storing the mixture at a low temperature to obtain a buffered electrolyte-bacterial culture medium mixture; (2) mixing the buffered electrolyte and bacterial culture medium mixture with sodium chloride and storing the mixture at low temperature to obtain a buffered electrolyte for sterilization; (3) preparing a low-coordination platinum single-atom catalyst modified electrode by preparing the low-coordination platinum single-atom catalyst; (4) inserting the low-coordination platinum single-atom catalyst modified electrode as a cathode and an anode respectively into the sterilization buffer electrolyte described in step (2), and performing electrolysis by applying power to obtain a sterilization buffer electrolyte.

6. The preparation method according to claim 5, characterized in that: The method further comprises: (5) Incubate the bacteria in the sterilized buffered electrolyte on a solid culture medium to obtain the number of colonies after sterilization.

7. The preparation method according to claim 5 or 6, characterized in that: In the step (1), the concentration of the bacteria in the buffered electrolyte-bacteria culture medium mixture is not less than 10^5 CFU / mL; And / or, in step (1), the buffered electrolyte includes at least one of a phosphate buffered saline solution and a bicarbonate buffer solution; And / or, in step (1), the volume ratio of the buffered electrolyte to the bacterial culture medium solution is not greater than 10:1; And / or, in step (1), the cryopreservation temperature does not exceed 4°C; And / or, in the step (2), the sodium chloride in the sterilization buffer electrolyte is 0.12 mol / L to 1.0 mol / L; And / or, in step (2), the temperature of the cryopreservation does not exceed 4°C.

8. The preparation method according to any one of claims 5 to 7, characterized in that: In the step (3), the total volume of the dispersion is between 0.5 mL and 1 mL; And / or, in the step (3), the concentration of the low-coordinated platinum single-atom catalyst in the dispersion is 0.5 mg / mL to 10 mg / mL; And / or, in step (3), the solvent of the dispersion liquid includes ethanol, deionized water, At least one of D-521 and isopropyl alcohol; And / or, in step (3), the dispersion needs to be treated under ultrasonic conditions for 0.5h to 2h; And / or, in the step (3), the modification amount of the low-coordination platinum single-atom catalyst on the modified electrode is 3 mg / cm 2 ~30mg / cm 2 ; And / or, in step (3), the modified electrode is a glassy carbon electrode; And / or, in step (3), the electrode diameter of the modified electrode is 3 mm to 5 mm; And / or, in step (3), the number of modified electrodes is not less than 2.

9. The preparation method according to any one of claims 5 to 8, characterized in that: In the step (4), the amount of the sterilization buffer electrolyte added is 2 mL to 10 mL; And / or, the voltage of the electrolysis is 1.0V to 1.8V; And / or, the time of the electrolysis is 0.05h to 1h.

10. The preparation method according to any one of claims 5 to 9, characterized in that: In the step (5), the inoculation amount of the buffered electrolyte after the electrolysis on the solid culture medium is 1 μL to 20 μL; And / or, the bacterial culture temperature is 36°C; And / or, the bacterial culture time is 6h to 12h; And / or, the solid culture medium comprises agar, sodium chloride, peptone, yeast extract and sodium hydroxide.

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