Method for preparing metal oxide or metal hydroxide nano thin-film material by molten salt method

Abstract

Provided is a method for preparing a metal oxide or a metal hydroxide nano thin-film material by a molten salt method, which mainly comprises the following steps: heating a low-melting-point salt to a molten state, adding a substrate into the molten salt before or after melting for reaction; adding a metal source and continuing the reaction for a period of time; removing the substrate, cooling the substrate to a room temperature, cleaning and drying the substrate to obtain the metal oxide or metal hydroxide nano thin-film material; wherein, the mass ratio of the low-melting-point salt to the metal source is 100-1.5:1. The metal oxide and metal hydroxide nano-film materials with various nano-morphologies prepared by the method of the present application have morphologies that can be regulated and controlled by the types and proportions of the low-melting-point salts and metal sources.

Claims

1. A method for preparing a metal oxide or a metal hydroxide nano thin-film material by a molten salt method, comprising the following steps: heating a low-melting-point salt to a molten state, adding a substrate into the molten salt before or after melting and reaction will occur for 5 s to 1 h; then adding a metal source, continuing to raise a temperature or keeping the temperature unchanged, and reaction will occur for a predetermined period of time; removing the substrate, cooling the substrate to a room temperature, cleaning and drying the substrate to obtain metal oxide or metal hydroxide nano thin-film material; wherein, a mass ratio of the low-melting-point salt to the metal source is 100-1.5:1; the substrate is FTO conductive glass, metal titanium foil, 304 stainless steel metal, metal copper foil, nickel foam, carbon felt cloth, carbon paper or carbon fiber cloth; the low-melting-point salt refers to a salt with a melting point lower than 400° C., comprising nitrate, chloride, sulfate, phosphate, acetate or carbonate; the metal source comprises nitrate, sulfate, chloride, phosphate, titanate, tungstate, acetate, molybdate or carbonate of any one of metal elements of copper, manganese, nickel, cobalt, zinc, iron, titanium, aluminum, vanadium, chromium, molybdenum, ruthenium, tungsten, zirconium, lanthanum and cerium; a range of raising the temperature is between a melting point and a decomposition temperature or a boiling point of the low-melting-point salt, and the predetermined period of time is 5s to 5h.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a field emission scanning electron microscope photograph of a MnO.sub.2/nickel foam film prepared in Example 1.

(2) FIG. 2 is a field emission scanning electron microscope photograph of a CuO/carbon fiber cloth film prepared in Example 2.

(3) FIG. 3 is a field emission scanning electron microscope photograph of a CuO/carbon fiber cloth film prepared in Example 3.

(4) FIG. 4 is a field emission scanning electron microscope photograph of a NiO/carbon felt film prepared in Example 4.

(5) FIG. 5 is a cyclic voltammetric graph of a Ni(OH).sub.2/carbon fiber cloth film prepared in Example 5.

(6) FIG. 6 is the X-ray diffraction patterns of metal oxide nano films prepared in Examples 6 to 14, specifically: a is Mn.sub.3O.sub.4/carbon fiber cloth film prepared in Example 6, b is a MnO.sub.2/304 stainless steel film prepared in Example 7, c is a MnO.sub.2/FTO conductive glass film prepared in Example 8, d is a MnO.sub.2/metal titanium foil film prepared in Example 9, e is a CuO/ carbon fiber cloth film prepared in Example 10, f is a CuO/carbon fiber cloth film prepared in Example 11, g is a CuO/carbon fiber cloth film prepared in Example 12, h is a Co.sub.3O.sub.4/carbon fiber cloth film prepared in Example 13, and i is a Co.sub.3O.sub.4/carbon felt film prepared in Example 14.

DESCRIPTION OF EMBODIMENTS

(7) The present application will be further illustrated with examples below, but the present application is not limited to the following examples.

(8) Example 1

(9) (1) Foam nickel with a size of 4×2 cm.sup.2 was selected as a substrate, an oxide layer was removed from the substrate with 10% hydrochloric acid, ultrasonically vibrated with deionized water, and completely dried in vacuum for subsequent use; (2) 10 g sodium nitrate was melted at 350° C.; (3) after sodium nitrate was completely melted, foam nickel was added to react for 1 minute; (4) 0.1 g manganese sulfate was added into the reaction system of the foam nickel and sodium nitrate, the system temperature was kept unchanged, and the reaction was continued for 1 minute; (5) the manganese oxide/nickel foam nano film obtained in step (4) was taken out, cooled to room temperature, and ultrasonically cleaned with deionized water; (6) the cleaned product was completely dried to obtain a manganese oxide/nickel foam nano thin-film material. The field emission scanning electron microscope photograph of the obtained nano-film material is shown in FIG. 1. The observation results of the surface morphology showed that the surface of the film was an array of manganese oxide nanoribbons perpendicular to the plane of nickel foam, and one side of the four nanoribbons was connected to form a pointed radial shape. The thickness of the nanoplatelets was about 5 nm and the length was about 1 μm.

(10) Example 2

(11) (1) A carbon fiber cloth with a size of 4×2 cm.sup.2 was selected as a substrate, and the substrate was ultrasonically washed with deionized water and dried for subsequent use; (2) 4.3 g of potassium nitrate was melted at 380° C.; (3) after potassium nitrate was completely melted, carbon fiber cloth was added to react for 2 minutes; (4) 2.9 g of copper chloride was added into the reaction system of the carbon fiber cloth and potassium nitrate, the temperature was raised by 10° C., and reaction was continued for 30 seconds; (5) the copper oxide/carbon fiber cloth nano film obtained in step (4) was taken out, cooled to the room temperature, and ultrasonically cleaned with deionized water; (6) the cleaned product was completely dried to obtain a copper oxide/carbon fiber cloth nano thin-film material. The field emission scanning electron microscope photos of the obtained nano-film materials are shown in FIG. 2. The observation results of surface morphology showed that the surface of the film has nano-particles growing from head to tail one after another, and the nano-structure layer was uniform and dense, with the length of the nano-particles about 50 nm and the width of nano-particles about 10 nm.

(12) Example 3

(13) (1) A carbon fiber cloth with a size of 4×2 cm.sup.2 was selected as a substrate, and the substrate was ultrasonically washed with deionized water and dried for subsequent use; (2) 2.6 g of potassium nitrate was melted at 380° C.; (3) after potassium nitrate was completely melted, carbon fiber cloth was added to react for 10 minutes; (4) 0.17 g of copper nitrate was added into the reaction system of the carbon fiber cloth and potassium nitrate, the system temperature was kept unchanged, and the reaction was continued for 10 seconds; (5) the copper oxide/carbon fiber cloth nano film obtained in step (4) was taken out, cooled to the room temperature, and ultrasonically cleaned with deionized water; (6) the cleaned product was completely dried to obtain a copper oxide/carbon fiber cloth nano cloth film material. The field emission scanning electron microscope photos of the obtained nano-film materials are shown in FIG. 3. The observation results of surface morphology showed that the surface of the film has uniformly distributed nanorods with a length of about 400 nm and a width of about 15 nm.

(14) Example 4

(15) (1) A carbon felt with a size of 4×2 cm.sup.2 was selected as a substrate, the substrate was ultrasonically vibrated with deionized water, and dried for subsequent use; (2) 2 g sodium nitrate was melted at 350° C.; (3) after sodium nitrate was completely melted, carbon felt cloth was added to react for 5 minutes; (4) 0.13 g of nickel nitrate was added into the reaction system of the carbon felt cloth and sodium nitrate, the temperature was raised by 5° C. and reaction was continued for 10 seconds; (5) the nickel oxide/carbon felt nano film obtained in step (4) was taken out, cooled to the room temperature, and ultrasonically cleaned with deionized water; (6) the cleaned product was completely dried to obtain a nickel oxide/carbon felt nano thin-film material. The field emission scanning electron microscope photograph of the obtained nano-thin film material was shown in FIG. 4. The observation results of surface morphology showed that the surface of the film has cross-grown nano-cubic crystals with a thickness of about 50 nm, an aspect ratio of about 1:1 and a size of about 200 nm.

(16) Example 5

(17) (1) A carbon fiber cloth with a size of 4×2 cm.sup.2 was selected as a substrate, and the substrate was ultrasonically washed with deionized water and dried for subsequent use; (2) 5 g of potassium nitrate was melted at 380° C.; (3) after the potassium nitrate was completely melted, carbon fiber cloth was added to react for 0.5 hours; (4) 0.3 g of nickel nitrate was added into the reaction system of the carbon fiber cloth and potassium nitrate, the temperature was raised by 5° C. and reaction was continued for 10 seconds; (5) the nickel hydroxide/carbon fiber cloth nano film obtained in step (4) was taken out, cooled to the room temperature, and ultrasonically cleaned with deionized water; (6) the cleaned product was completely dried to obtain a nickel hydroxide/carbon fiber cloth nano thin-film material. The obtained nano-film material can be directly used as an electrode, and its cyclic voltammetric curve is shown in FIG. 5. The electrochemical performance results showed that the area specific capacitance was 1785.25 mF cm.sup.−2 after voltage scanning at a speed of 2 mV s.sup.−1 in 6 M potassium hydroxide electrolyte, which showed that the nickel oxide/carbon fiber cloth nano-film array prepared by this method had excellent electrochemical performance and good application prospect for electrochemical energy storage.

(18) Example 6

(19) (1) A carbon fiber cloth with a size of 4×2 cm.sup.2 was selected as a substrate, and the substrate was ultrasonically washed with deionized water and dried for subsequent use; (2) 5 g of potassium nitrate was melted at 380° C.; (3) after the potassium nitrate was completely melted, carbon fiber cloth was added to react for 0.5 hours; (4) 0.5 g manganese chloride was added into the reaction system of the carbon fiber cloth and potassium nitrate, the temperature was raised by 2° C. and the reaction was continued for 40 seconds; (5) the Mn.sub.3O.sub.4/carbon fiber cloth nano film obtained in step (4) was taken out, cooled to the room temperature, and ultrasonically cleaned with deionized water; (6) the cleaned product was completely dried to obtain a Mn.sub.3O.sub.4/carbon fiber cloth nano thin-film material. The X-ray diffraction pattern of the obtained nano-film material is shown in curve a of FIG. 6. The results showed that the oxide was manganic oxide. According to the standard card PDF #80-0382, the strongest peak at 36.08 corresponded to the (211) crystal plane of manganic oxide, and the second strongest peak at 32.4 corresponded to the (103) crystal plane.

(20) Example 7

(21) (1) 304 stainless steel with a size of 4×2 cm.sup.2 was selected as a substrate, and the substrate was cleaned with 10% hydrochloric acid first, then ultrasonically washed with deionized water and dried for subsequent use; (2) 5 g of potassium nitrate was melted at 380° C.; (3) after potassium nitrate was completely melted, stainless steel was added to react for 1 hour; (4) 0.25 g manganese sulfate was added into the reaction system of the stainless steel and potassium nitrate, the temperature was raised by 10° C., and reaction was continued for 0.5 h; (5) the MnO.sub.2/stainless steel nano film obtained in step (4) was taken out, cooled to the room temperature, and ultrasonically cleaned with deionized water; (6) the cleaned product was completely dried to obtain a MnO.sub.2/stainless steel nano thin-film material. The X-ray diffraction pattern of the obtained nano-thin film material is shown in Curve B of FIG. 6. The results showed that the oxide was a mixed phase of manganese dioxide and manganese tetroxide.

(22) Example 8

(23) (1) FTO conductive glass with a size of 4×2 cm.sup.2 was selected as a substrate, the substrate was ultrasonically washed with deionized water, and dried for subsequent use; (2) 5 g of potassium nitrate was melted at 380° C.; (3) after the potassium nitrate was completely melted, and FTO was added to react for 10 seconds; (4) 0.25 g manganese sulfate was added into the reaction system of FTO and potassium nitrate, the temperature was raised by 10° C. and reaction was continued for 10 seconds; (5) the MnO.sub.2/FTO conductive glass nano film obtained in step (4) was taken out, cooled to the room temperature, and ultrasonically cleaned with deionized water; (6) the cleaned product was completely dried to obtain a MnO.sub.2/FTO conductive glass nano thin-film material. The X-ray diffraction pattern of the obtained nano-film material is shown in curve C of FIG. 6. The results showed that the oxide was manganese dioxide.

(24) Example 9

(25) (1) A metal Ti foil with a size of 4×2 cm.sup.2 was selected as a substrate, the substrate was ultrasonically washed with deionized water, and dried for subsequent use; (2) 3 g sodium nitrate was melted at 350° C.; (3) titanium foil was added to react for 10 seconds after sodium nitrate was completely melted; (4) 0.17 g manganese sulfate was added into the reaction system of titanium foil and sodium nitrate, the temperature was raised by 10° C. and reaction was continued for 10 seconds; (5) the MnO.sub.2/titanium foil nano film obtained in step (4) was taken out, cooled to the room temperature, and ultrasonically cleaned with deionized water; (6) the cleaned product was completely dried to obtain MnO.sub.2/titanium foil nano thin-film material. The X-ray diffraction pattern of the obtained nano-film material is shown in Curve D of FIG. 6. The results showed that the oxide was a mixed phase of manganese dioxide and manganese trioxide.

(26) Example 10

(27) (1) A carbon fiber cloth with a size of 4×2 cm.sup.2 was selected as a substrate, the substrate was ultrasonically washed with deionized water, and dried for subsequent use; (2) 2.5 g sodium nitrate was melted at 350° C.; (3) the carbon fiber cloth was added to react for 1 hour after sodium nitrate was completely melted; (4) 0.15 g copper sulfate was added into the reaction system of carbon fiber cloth and sodium nitrate, the temperature was raised by 10° C. and reaction was continued for 30 seconds; (5) the CuO/carbon fiber cloth nano film obtained in step (4) was taken out, cooled to room temperature, and ultrasonically cleaned with deionized water; (6) the cleaned product was completely died to obtain a CuO/carbon fiber cloth nano thin-film material. The X-ray diffraction pattern of the obtained nano-film material is shown in curve E of FIG. 6. The results showed that the oxide was copper oxide.

(28) Example 11

(29) (1) A carbon fiber cloth with a size of 4×2 cm.sup.2 was selected as a substrate, the substrate was ultrasonically washed with deionized water, and dried for subsequent use; (2) 2.5 g sodium nitrate was melted at 350° C.; (3) the carbon fiber cloth was added to react for 1 hour after sodium nitrate was completely melted; (4) 0.1 g copper chloride was added into the reaction system of carbon fiber cloth and sodium nitrate, the temperature was raised by 10° C. and reaction was continued for 30 seconds; (5) the CuO/carbon fiber cloth nano film obtained in step (4) was taken out, cooled to the room temperature, and ultrasonically cleaned with deionized water; (6) the cleaned product was completely dried to obtain a CuO/carbon fiber cloth nano thin-film material. The X-ray diffraction pattern of the obtained nano-thin film material is shown in curve F of FIG. 6. The results showed that the oxide was copper oxide.

(30) Example 12

(31) (1) A carbon fiber cloth with a size of 4×2 cm.sup.2 was selected as a substrate, the substrate was ultrasonically washed with deionized water, and dried for subsequent use; (2) 2.5 g sodium nitrate was melted at 350° C.; (3) the carbon fiber cloth was added to react for 1 hour after sodium nitrate was completely melted; (4) 0.145 g copper nitrate was added into the reaction system of carbon fiber cloth and sodium nitrate, the temperature was raised by 10° C. and reaction was continued for 10 seconds; (5) the CuO/ carbon fiber cloth nano film obtained in step (4) was taken out, cooled to room temperature, and ultrasonically cleaned with deionized water; (6) the cleaned product was completely dried to obtain a CuO/ carbon fiber cloth nano thin-film material. The X-ray diffraction pattern of the obtained nano-film material is shown in curve G of FIG. 6. The results showed that the oxide was copper oxide.

(32) Example 13

(33) (1) A carbon fiber cloth with a size of 4×2 cm.sup.2 was selected as a substrate, the substrate was ultrasonically washed with deionized water, and dried for subsequent use; (2) 2.5 g of potassium nitrate was melted at 380° C.; (3) after the potassium nitrate was completely melted, the carbon fiber cloth was added to react for 0.5 hours; (4) 0.143 g cobalt chloride was added into the reaction system of carbon fiber cloth and potassium nitrate, the temperature was raised by 10° C., and reaction was continued for 10 seconds; (5) the Co.sub.3O.sub.4/carbon fiber cloth nano film obtained in step (4) was taken out, cooled to the room temperature, and ultrasonically cleaned with deionized water; (6) the cleaned product was completely dried to obtain a Co.sub.3O.sub.4/carbon fiber cloth nano thin-film material. The X-ray diffraction pattern of the obtained nano-film material is shown in curve H of FIG. 6. The results showed that the oxide was cobaltosic oxide.

(34) Example 14

(35) (1) A carbon felt cloth with a size of 4×2 cm.sup.2 was selected as a substrate, the substrate was ultrasonically washed with deionized water, and dried for subsequent use; (2) 2.5 g of potassium nitrate was melted at 380° C.; (3) after the potassium nitrate was completely melted, the carbon fiber cloth was added to react for 0.5 hours; (4) 0.17 g cobalt nitrate was added into the reaction system of carbon felt cloth and potassium nitrate, the melting temperature of potassium nitrate was kept unchanged, and reaction was continued for 10 seconds; (5) the Co.sub.3O.sub.4/carbon felt nano film obtained in step (4) was taken out, cooled to room temperature, and ultrasonically cleaned with deionized water; (6) the cleaned product was completely dried to obtain a Co.sub.3O.sub.4/carbon felt nano thin-film material. The X-ray diffraction pattern of the obtained nano-film material is shown in Curve I of FIG. 6. The results showed that the oxide was cobaltosic oxide.

(36) The X-ray diffraction patterns of metal oxide nano-film materials prepared in Examples 6 to 14 of the present application were as follows: a was a Mn.sub.3O.sub.4/carbon fiber cloth film prepared in Example 6, b was a MnO.sub.2/304 stainless steel film prepared in Example 7, c was a MnO.sub.2/FTO conductive glass film prepared in Example 8, d is MnO.sub.2/metal titanium foil film prepared in Example 9, e was CuO/carbon fiber cloth film prepared in Example 10, f was a CuO/carbon fiber cloth film prepared in Example 11, g was CuO/carbon fiber cloth film prepared in Example 12, h was Co.sub.3O.sub.4/carbon fiber cloth film prepared in Example 13, and i was a Co.sub.3O.sub.4/carbon felt film prepared in Example 14. Comparing the curves a-d of FIG. 6, it can be seen that various oxides of manganese metal can be grown on different substrates by adjusting different preparation parameters and raw materials.

(37) Comparing the relative peak intensity of diffraction peak of e-g curves in FIG. 6, it can be seen that the quality of the nano-array of CuO/carbon fiber cloth film can be controlled by adjusting the preparation parameters on the same substrate. It can be further seen from the curves h-i of FIG. 6 that this preparation technology is suitable for various kinds of metal oxides.

(38) The above examples and applications are the specific embodiments of the technical solution of the present application, and are used to further describe the technical solution of the present application. However, the design concept of the present application is not limited thereto, and any simple modifications, equivalent changes or improvements made according to the technical essence of the present application should still be within the protection scope of the technical solution of the present application.