INTEREMBEDDED AUTOGENOUS TUNGSTEN (MOLYBDENUM)-COPPER ALLOY POWDER, AND PREPARATION METHOD AND USE THEREOF

Abstract

An interembedded autogenous tungsten (molybdenum)-copper alloy powder, and a preparation method and use thereof are provided. By controlling concentration and type of an organic complex, positive ion metal salts and negative ion metal groups form coordination bonds with hydroxyl oxygen and carboxyl carbon of the organic complex so as to form complexes, respectively. A stepwise heat treatment is conducted to controllably prepare a tungsten (molybdenum)-copper alloy powder with a unique interembedded autogenous structure.

Claims

1. A method for preparing an interembedded autogenous tungsten-copper alloy powder, comprising the following steps: (1) preparing an aqueous solution of a soluble copper salt, and adding an organic complex into the aqueous solution of the soluble copper salt to obtain a mixed solution A; (2) preparing an aqueous solution of a soluble tungsten salt, adding the aqueous solution of the soluble tungsten salt into the mixed solution A, stirring continuously while heating, and concentrating a resulting mixture to obtain a gel, and then drying the gel through a drying oven to obtain a precursor; (3) calcining the precursor in air to obtain a tungsten-copper composite metal oxide powder; and (4) subjecting the tungsten-copper composite metal oxide powder to thermal reduction in an argon-hydrogen atmosphere to obtain the interembedded autogenous tungsten-copper alloy powder.

2. The method of claim 1, wherein in step (1), the soluble copper salt is one or more selected from the group consisting of copper nitrate and copper sulfate; the aqueous solution of the soluble copper salt has a concentration of 0.01 mol/L to 2.3 mol/L; the organic complex is one or more selected from the group consisting of lactic acid, glycolic acid, and gelatin; and under a condition that the organic complex is the lactic acid or the glycolic acid, a molar ratio of the lactic acid or the glycolic acid to the soluble copper salt is in a range of greater than 1:1.

3. The method of claim 1, wherein in step (2), the soluble tungsten salt is one or more selected from the group consisting of ammonium metatungstate and sodium tungstate, and the aqueous solution of the soluble tungsten salt has a concentration of 0.01 mol/L to 1.0 mol/L; a volume ratio of the aqueous solution of the soluble tungsten salt to the aqueous solution of the soluble copper salt is 1:1; the resulting mixture is concentrated after heating to a temperature of 30 C. to 50 C. to obtain a gel; and the drying is conducted in the drying oven at a temperature of 80 C. to 120 C. for 2 h to 6 h.

4. The method of claim 1, wherein in step (3), calcining the precursor in the air is conducted by the following two stages: heating the precursor from room temperature to a first-stage calcination temperature, and calcining the precursor at the first-stage calcination temperature for a period of time; and heating a resulting material from the first-stage calcination temperature to a second-stage calcination temperature, and calcining the resulting material at the second-stage calcination temperature for a period of time.

5. The method of claim 1, wherein in step (3), heating the precursor from the room temperature to the first-stage calcination temperature is conducted at a heating rate of 0.5 C./min to 6 C./min, and heating the resulting material from the first-stage calcination temperature to the second-stage calcination temperature is conducted at a heating rate of 5 C./min to 13 C./min; the first-stage calcination temperature is in a range of 250 C. to 420 C., and calcining the precursor at the first-stage calcination temperature is conducted for 2 h to 7 h; and the second-stage calcination temperature is in a range of 450 C. to 600 C., and calcining the resulting material at the second-stage calcination temperature is conducted for 1 h to 5 h.

6. The method of claim 1, wherein in step (4), the thermal reduction is conducted by the following two stages: in the argon-hydrogen atmosphere, heating the tungsten-copper composite metal oxide powder from room temperature to a first-stage reduction temperature, and reducing the tungsten-copper composite metal oxide powder at the first-stage reduction temperature for a period of time; and heating a resulting powder from the first-stage reduction temperature to a second-stage reduction temperature, and reducing the resulting powder at the second-stage reduction temperature for a period of time.

7. The method of claim 6, wherein in step (4), in the argon-hydrogen atmosphere, heating the tungsten-copper composite metal oxide powder from the room temperature to the first-stage reduction temperature is conducted at a heating rate of 0.2 C./min to 5 C./min, and heating the resulting powder from the first-stage reduction temperature to the second-stage reduction temperature is conducted at a heating rate of 3 C./min to 6 C./min; the first-stage reduction temperature is in a range of 300 C. to 450 C., and reducing the tungsten-copper composite metal oxide powder at the first-stage reduction temperature is conducted for 2 h to 5 h; the second-stage reduction temperature is in a range of 750 C. to 850 C., and reducing the resulting powder at the second-stage reduction temperature is conducted for 1 h to 7 h; and the argon-hydrogen atmosphere has a hydrogen volume fraction of 5% to 15%.

8. A method for preparing an interembedded autogenous molybdenum-copper alloy powder, wherein the method is conducted according to the method of any one of claim 1, except that: in step (2), the aqueous solution of the soluble tungsten salt is replaced by an aqueous solution of a soluble molybdenum salt, the soluble molybdenum salt is one or more selected from the group consisting of sodium molybdate and ammonium molybdate, the aqueous solution of the soluble molybdenum salt has a concentration of 0.01 mol/L to 1.0 mol/L, and a volume ratio of the aqueous solution of the soluble molybdenum salt to the aqueous solution of the soluble copper salt is 1:1; in step (3), a molybdenum-copper composite metal oxide powder is obtained; and in step (4), the molybdenum-copper composite metal oxide powder is subjected to the thermal reduction in the argon-hydrogen atmosphere to obtain the interembedded autogenous molybdenum-copper alloy powder.

9. The method of claim 8, wherein in step (1), the soluble copper salt is one or more selected from the group consisting of copper nitrate and copper sulfate; the aqueous solution of the soluble copper salt has a concentration of 0.01 mol/L to 2.3 mol/L; the organic complex is one or more selected from the group consisting of lactic acid, glycolic acid, and gelatin; and under a condition that the organic complex is the lactic acid or the glycolic acid, a molar ratio of the lactic acid or the glycolic acid to the soluble copper salt is in a range of greater than 1:1.

10. The method of claim 8, wherein in step (2), the resulting mixture is concentrated after heating to a temperature of 30 C. to 50 C. to obtain a gel; and the drying is conducted in the drying oven at a temperature of 80 C. to 120 C. for 2 h to 6 h.

11. The method of claim 8, wherein in step (3), calcining the precursor in the air is conducted by the following two stages: heating the precursor from room temperature to a first-stage calcination temperature, and calcining the precursor at the first-stage calcination temperature for a period of time; and heating a resulting material from the first-stage calcination temperature to a second-stage calcination temperature, and calcining the resulting material at the second-stage calcination temperature for a period of time.

12. The method of claim 8, wherein in step (3), heating the precursor from the room temperature to the first-stage calcination temperature is conducted at a heating rate of 0.5 C./min to 6 C./min, and heating the resulting material from the first-stage calcination temperature to the second-stage calcination temperature is conducted at a heating rate of 5 C./min to 13 C./min; the first-stage calcination temperature is in a range of 250 C. to 420 C., and calcining the precursor at the first-stage calcination temperature is conducted for 2 h to 7 h; and the second-stage calcination temperature is in a range of 450 C. to 600 C., and calcining the resulting material at the second-stage calcination temperature is conducted for 1 h to 5 h.

13. The method of claim 8, wherein in step (4), the thermal reduction is conducted by the following two stages: in the argon-hydrogen atmosphere, heating the molybdenum-copper composite metal oxide powder from room temperature to a first-stage reduction temperature, and reducing the molybdenum-copper composite metal oxide powder at the first-stage reduction temperature for a period of time; and heating a resulting powder from the first-stage reduction temperature to a second-stage reduction temperature, and reducing the resulting powder at the second-stage reduction temperature for a period of time.

14. The method of claim 13, wherein in step (4), in the argon-hydrogen atmosphere, heating the molybdenum-copper composite metal oxide powder from the room temperature to the first-stage reduction temperature is conducted at a heating rate of 0.2 C./min to 5 C./min, and heating the resulting powder from the first-stage reduction temperature to the second-stage reduction temperature is conducted at a heating rate of 3 C./min to 6 C./min; the first-stage reduction temperature is in a range of 300 C. to 450 C., and reducing the molybdenum-copper composite metal oxide powder at the first-stage reduction temperature is conducted for 2 h to 5 h; the second-stage reduction temperature is in a range of 750 C. to 850 C., and reducing the resulting powder at the second-stage reduction temperature is conducted for 1 h to 7 h; and the argon-hydrogen atmosphere has a hydrogen volume fraction of 5% to 15%.

15. An interembedded autogenous tungsten-copper alloy powder prepared by the method of claim 1.

16. An interembedded autogenous molybdenum-copper alloy powder prepared by the method of claim 8.

17. A method of ethanol-assisted energy-saving hydrogen production, comprising using the interembedded autogenous tungsten-copper alloy powder of claim 15.

18. A method of ethanol-assisted energy-saving hydrogen production, comprising using the interembedded autogenous molybdenum-copper alloy powder of claim 16.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG. 1A shows a field emission scanning electron microscopy (FESEM) image of the interembedded autogenous tungsten-copper alloy powder prepared in Example 1 at a low magnification;

[0030] FIG. 1B shows an FESEM image of the interembedded autogenous tungsten-copper alloy powder prepared in Example 1 at a medium magnification;

[0031] FIG. 1C shows an FESEM image of the interembedded autogenous tungsten-copper alloy powder prepared in Example 1 at a high magnification;

[0032] FIG. 2A shows an FESEM image of the interembedded autogenous tungsten-copper alloy powder prepared in Example 2 at a low magnification;

[0033] FIG. 2B shows an FESEM image of the interembedded autogenous tungsten-copper alloy powder prepared in Example 2 at a medium magnification;

[0034] FIG. 2C shows an FESEM image of the interembedded autogenous tungsten-copper alloy powder prepared in Example 2 at a high magnification;

[0035] FIG. 3A shows an FESEM image of the interembedded autogenous tungsten-copper alloy powder prepared in Example 3 at a low magnification;

[0036] FIG. 3B shows an FESEM image of the interembedded autogenous tungsten-copper alloy powder prepared in Example 3 at a medium magnification;

[0037] FIG. 3C shows an FESEM image of the interembedded autogenous tungsten-copper alloy powder prepared in Example 3 at a high magnification;

[0038] FIG. 4A shows an FESEM images of the interembedded autogenous tungsten-copper alloy powder prepared in Example 4 at a low magnification;

[0039] FIG. 4B shows an FESEM images of the interembedded autogenous tungsten-copper alloy powder prepared in Example 4 at a medium magnification;

[0040] FIG. 4C shows an FESEM images of the interembedded autogenous tungsten-copper alloy powder prepared in Example 4 at a high magnification;

[0041] FIG. 5 shows X-ray diffraction (XRD) patterns of the interembedded autogenous tungsten-copper alloy powders prepared in Examples 1 to 4;

[0042] FIG. 6 shows a chronoamperometric curve of the interembedded autogenous molybdenum-copper alloy powder prepared in Example 5;

[0043] FIG. 7 shows a linear sweep voltammetry (LSV) curve of the interembedded autogenous molybdenum-copper alloy powder prepared in Example 6 in a 1 mol.Math.L.sup.1 KOH electrolyte; and

[0044] FIG. 8 shows a columnar comparison chart of the voltage required to achieve a current density of 100 mA cm.sup.2 in ethanol-assisted hydrogen production between the interembedded autogenous molybdenum-copper alloy powder prepared in Example 6 and different reported catalysts.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0045] In order to better understand the content of the present disclosure, the technical solutions of the present disclosure will be further described below with reference to examples. The following examples provide detailed implementation methods and operating steps based on the technical solutions of the present disclosure, but the scope of the present disclosure is not limited to the following examples.

EXAMPLE 1

[0046] (1) 360 mL of a copper nitrate aqueous solution was prepared with a concentration of 1.3 mol/L, and 60 g of lactic acid was added into the copper nitrate aqueous solution to obtain a mixed solution A.

[0047] (2) 360 mL of an ammonium metatungstate aqueous solution was prepared with a concentration of 0.2 mol/L. The ammonium metatungstate aqueous solution was added into the mixed solution A, stirred continuously and heated to 40 C., and a resulting solution was concentrated slowly to obtain a gel. The gel was dried in a drying oven at 80 C. for 6 h to obtain a precursor.

[0048] (3) The precursor was calcined in air, where the precursor was heated from room temperature to 250 C. at 5 C./min, and calcined at 250 C. for 3 h, and then a resulting material was heated from 250 C. to 500 C. at 5 C./min, and calcined at 500 C. for 3 h to obtain a tungsten-copper composite metal oxide powder.

[0049] (4) The tungsten-copper composite metal oxide powder was subjected to thermal reduction, where a reducing atmosphere was an argon-hydrogen mixture with a hydrogen volume fraction of 5%. The tungsten-copper composite metal oxide powder was heated from room temperature to 350 C. at 5 C./min, and reduced at 350 C. for 3 h, and then a resulting material was heated from 350 C. to 750 C. at 5 C./min, and reduced at 750 C. for 6 h to obtain an interembedded autogenous tungsten-copper alloy powder.

EXAMPLE 2

[0050] (1) 360 mL of a copper nitrate aqueous solution was prepared with a concentration of 1.6 mol/L, and 60 g of glycolic acid was added into the copper nitrate aqueous solution to obtain a mixed solution A.

[0051] (2) 360 mL of an ammonium metatungstate aqueous solution was prepared with a concentration of 0.23 mol/L. The ammonium metatungstate aqueous solution was added into the mixed solution A, stirred continuously and heated to 40 C., and a resulting solution was concentrated slowly to obtain a gel. The gel was dried in a drying oven at 80 C. for 6 h to obtain a precursor.

[0052] (3) The precursor was calcined in air, where the precursor was heated from room temperature to 250 C. at 5 C./min, and calcined at 250 C. for 3 h, and then a resulting material was heated from 250 C. to 500 C. at 5 C./min, and calcined at 500 C. for 3 h to obtain a tungsten-copper composite metal oxide powder.

[0053] (4) The tungsten-copper composite metal oxide powder was subjected to thermal reduction, where a reducing atmosphere was an argon-hydrogen mixture with a hydrogen volume fraction of 5%. The tungsten-copper composite metal oxide powder was heated from room temperature to 350 C. at 5 C./min, and reduced at 350 C. for 3 h, and then a resulting material was heated from 350 C. to 750 C. at 5 C./min, and reduced at 750 C. for 6 h to obtain an interembedded autogenous tungsten-copper alloy powder.

EXAMPLE 3

[0054] (1) 360 mL of a copper sulfate aqueous solution was prepared with a concentration of 1.0 mol/L, and 100 g of gelatin was added into the copper sulfate aqueous solution to obtain a mixed solution A.

[0055] (2) 360 mL of an ammonium metatungstate aqueous solution was prepared with a concentration of 0.23 mol/L. The ammonium metatungstate aqueous solution was added into the mixed solution A, stirred continuously and heated to 40 C., and a resulting solution was concentrated slowly to obtain a gel. The gel was dried in a drying oven at 80 C. for 6 h to obtain a precursor.

[0056] (3) The precursor was calcined in air, where the precursor was heated from room temperature to 250 C. at 5 C./min, and calcined at 250 C. for 3 h, and then a resulting material was heated from 250 C. to 450 C. at 5 C./min, and calcined at 450 C. for 3 h to obtain a tungsten-copper composite metal oxide powder.

[0057] (4) The tungsten-copper composite metal oxide powder was subjected to thermal reduction, where a reducing atmosphere was an argon-hydrogen mixture with a hydrogen volume fraction of 5%. The tungsten-copper composite metal oxide powder was heated from room temperature to 350 C. at 5 C./min, and reduced at 350 C. for 3 h, and then a resulting material was heated from 350 C. to 750 C. at 5 C./min, and reduced at 750 C. for 5 h to obtain an interembedded autogenous tungsten-copper alloy powder.

EXAMPLE 4

[0058] (1) 360 mL of a copper sulfate aqueous solution was prepared with a concentration of 2 mol/L, and 80 g of lactic acid was added into the copper sulfate aqueous solution to obtain a mixed solution A.

[0059] (2) 360 mL of a sodium tungstate aqueous solution was prepared with a concentration of 0.1 mol/L. The sodium tungstate aqueous solution was added into the mixed solution A, stirred continuously and heated to 40 C., and a resulting solution was concentrated slowly to obtain a gel. The gel was dried in a drying oven at 80 C. for 6 h to obtain a precursor.

[0060] (3) The precursor was calcined in air, where the precursor was heated from room temperature to 250 C. at 5 C./min, and calcined at 250 C. for 3 h, and then a resulting material was heated from 250 C. to 450 C. at 5 C./min, and calcined at 450 C. for 3 h to obtain a tungsten-copper composite metal oxide powder.

[0061] (4) The tungsten-copper composite metal oxide powder was subjected to thermal reduction, where a reducing atmosphere was an argon-hydrogen mixture with a hydrogen volume fraction of 5%. The tungsten-copper composite metal oxide powder was heated from room temperature to 350 C. at 5 C./min, and reduced at 350 C. for 3 h, and then a resulting material was heated from 350 C. to 750 C. at 5 C./min, and reduced at 750 C. for 5 h to obtain an interembedded autogenous tungsten-copper alloy powder.

EXAMPLE 5

[0062] (1) 360 mL of a copper nitrate aqueous solution was prepared with a concentration of 1.8 mol/L, and 80 g of lactic acid was added into the copper nitrate aqueous solution to obtain a mixed solution A.

[0063] (2) 360 mL of a sodium molybdate aqueous solution was prepared with a concentration of 0.3 mol/L. The sodium molybdate aqueous solution was added into the mixed solution A, stirred continuously and heated to 40 C., and a resulting solution was concentrated slowly to obtain a gel. The gel was dried in a drying oven at 80 C. for 6 h to obtain a precursor.

[0064] (3) The precursor was calcined in air, where the precursor was heated from room temperature to 250 C. at 5 C./min, and calcined at 250 C. for 3 h, and then a resulting material was heated from 250 C. to 500 C. at 5 C./min, and calcined at 500 C. for 3 h to obtain a molybdenum-copper composite metal oxide powder.

[0065] (4) The molybdenum-copper composite metal oxide powder was subjected to thermal reduction, where a reducing atmosphere was an argon-hydrogen mixture with a hydrogen volume fraction of 5%. The molybdenum-copper composite metal oxide powder was heated from room temperature to 350 C. at 5 C./min, and reduced at 350 C. for 3 h, and then a resulting material was heated from 350 C. to 850 C. at 5 C./min, and reduced at 850 C. for 6 h to obtain an interembedded autogenous molybdenum-copper alloy powder.

EXAMPLE 6

[0066] (1) 360 mL of a copper sulfate aqueous solution was prepared with a concentration of 2.2 mol/L, and 90 g of glycolic acid was added into the copper sulfate aqueous solution to obtain a mixed solution A.

[0067] (2) 360 mL of an ammonium molybdate aqueous solution was prepared with a concentration of 0.35 mol/L. The ammonium molybdate aqueous solution was added into the mixed solution A, stirred continuously and heated to 40 C., and a resulting solution was concentrated slowly to obtain a gel. The gel was dried in a drying oven at 80 C. for 6 h to obtain a precursor.

[0068] (3) The precursor was calcined in air, where the precursor was heated from room temperature to 250 C. at 5 C./min, and calcined at 250 C. for 3 h, and then a resulting material was heated from 250 C. to 550 C. at 5 C./min, and calcined at 550 C. for 3 h to obtain a molybdenum-copper composite metal oxide powder.

[0069] (4) The molybdenum-copper composite metal oxide powder was subjected to thermal reduction, where a reducing atmosphere was an argon-hydrogen mixture with a hydrogen volume fraction of 5%. The molybdenum-copper composite metal oxide powder was heated from room temperature to 350 C. at 5 C./min, and reduced at 350 C. for 3 h, and then a resulting material was heated from 350 C. to 850 C. at 5 C./min, and reduced at 850 C. for 6 h to obtain an interembedded autogenous molybdenum-copper alloy powder.

[0070] FIG. 1A, FIG. 1B and FIG. 1C are FESEM images of the interembedded autogenous tungsten-copper alloy powder prepared in Example 1 at different magnifications, indicating that the tungsten-copper alloy has an interembedded autogenous structure in which tungsten is scattered and grown on the copper surface.

[0071] FIG. 2A, FIG. 2B and FIG. 2C are FESEM images of the interembedded autogenous tungsten-copper alloy powder prepared in Example 2 at different magnifications, indicating that the tungsten-copper alloy has an interembedded autogenous structure in which tungsten grows uniformly on the copper surface.

[0072] FIG. 3A, FIG. 3B and FIG. 3C are FESEM images of the interembedded autogenous tungsten-copper alloy powder prepared in Example 3 at different magnifications, indicating that in the tungsten-copper alloy, tungsten grows on the copper surface, forming an interembedded autogenous structure of tungsten-cladded copper.

[0073] FIG. 4A, FIG. 4B and FIG. 4C are FESEM images of the interembedded autogenous tungsten-copper alloy powder prepared in Example 4 at different magnifications, indicating that the tungsten-copper alloy has an interembedded autogenous structure in which tungsten grows sparsely on the copper surface.

[0074] FIG. 5 shows XRD patterns of the interembedded autogenous tungsten-copper alloy powders prepared in Examples 1 to 4. From FIG. 5, it can be seen that strong diffraction peaks can be observed in the corresponding patterns, and their peak positions are all at the positions of Cu (PDF #04-0836) and tungsten (PDF #04-0806), indicating that all products prepared in Examples 1 to 4 are tungsten-copper alloys.

[0075] According to the manufacturing method of the working electrode, the interembedded autogenous molybdenum-copper alloy powder prepared in Example 5 was used as a working electrode for electrochemical testing. The chronocurrent curve at a current density of 100 mA cm.sup.2 is shown in FIG. 6.

[0076] The working electrode was prepared as follows: about 10 mg of sample was added into a 10 mL centrifuge tube, deionized water and absolute ethanol were added into the centrifuge tube in a ratio of 4:1 to reach a sample concentration of 2 mg mL.sup.1; a resulting suspension was sonicated until it was evenly dispersed, and then 250 L of the evenly dispersed suspension was added dropwise into a 11 cm.sup.2 foamed nickel electrode, and then 25 L of a Nafion aqueous solution was evenly dispersed on an surface of the electrode and dried at 60 C. for 15 min to obtain the working electrode for electrochemical testing.

[0077] The electrochemical testing was conducted on an electrochemical workstation (CHI-660E, CHI Instruments, Shanghai, China) using 1 mol L.sup.1 KOH and 1 mol L.sup.1 ethanol as electrolytes, a platinum electrode as a counter electrode, and the sample as the working electrode, at a scan rate of 5 mV.Math.s.sup.1.

[0078] The stability test results in FIG. 6 show that after the interembedded autogenous molybdenum-copper alloy powder prepared in Example 6 as a catalyst works for 100 h at an initial operating current density of 100 mA cm.sup.2, the current density of the sample drops to 87.3 mA cm.sup.2, with a retention rate of 87.3%, indicating a desirable stability.

[0079] According to the above manufacturing method of the working electrode, the interembedded autogenous molybdenum-copper alloy powder prepared in Example 6 was used as a working electrode for electrochemical testing. The LSV curve in the electrolyte of 1 mol L.sup.1 KOH and the LSV curve in the electrolyte of 1 mol L.sup.1 KOH and 1 mol L.sup.1 ethanol are shown in FIG. 7. A columnar comparison chart of the voltage required to achieve a current density of 100 mA cm.sup.2 in ethanol-assisted hydrogen production by using the interembedded autogenous molybdenum-copper alloy powder catalyst prepared in Example 6 and other reported catalysts is shown in FIG. 8.

[0080] The performance test results in FIG. 7 show that the interembedded autogenous molybdenum-copper alloy powder prepared in Example 6 as a catalyst has an operating voltage of 1.4 V at a current density of 100 mA cm.sup.2 in an electrolyte of 1 mol L.sup.1 KOH (that is, the operating voltage of hydrogen production by electrolysis of water is 1.4 V); and the catalyst has an operating voltage of 1.28 V at a current density of 100 mA cm.sup.2 in an electrolyte of 1 mol L.sup.1 KOH and 1 mol L.sup.1 ethanol. These indicate that the ethanol-assisted hydrogen production has a lower operating voltage than the hydrogen production by electrolysis of water. The columnar comparison in FIG. 8 shows that in the field of ethanol-assisted energy-saving hydrogen production, the interembedded autogenous molybdenum-copper alloy has an operating voltage lower than that of other reported catalysts at a current density of 100 mA cm.sup.2 and exhibits an excellent catalytic activity.

[0081] The above are merely preferred embodiments of the present disclosure rather than limitations on the present disclosure in any form. The present disclosure can also have other forms of embodiments based on the above structures and functions, which are not be listed one by one. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments according to the technical essence of the present disclosure without departing from the contents of the technical solutions of the present disclosure still fall within the scope of the technical solutions of the present disclosure.