Silicon carbide nanomaterial, and preparation method and application thereof

Abstract

The application discloses a silicon carbide nanometer material and a preparation method and application thereof, and belongs to the technical field of functional materials. The silicon carbide nanometer material is composed of silicon carbide nanometer wires and nanoparticles; the silicon carbide is composed of rhombohedral SiC and is a single crystal structure with the same lattice direction; the diameter of the nanometer wire is 30-400 nm, and the length is greater than 10 microns. The preparation method of the silicon carbide nanometer electrode material is as follows: chicken manure, silicon sol and distilled water are mixed, and the mixture is added into a sealed container; the mixture is kept at 80-150 DEG C for 1-5 hours; after cooling, the chicken manure silicon dioxide precursor is obtained by drying; the chicken manure silicon dioxide precursor, calcium chloride and sodium chloride are fully mixed, then the mixture is loaded into a crucible, the crucible is placed in a vacuum reaction furnace, and the silicon carbide nanometer material is obtained by keeping the temperature at 800-1000 DEG C for 1-3 hours under the protection of nitrogen. The two-step synthesis process is easy to control, and the agricultural organic waste is converted into treasure. The silicon carbide nanometer material has a good application prospect as an electrode material in the electrocatalytic detection of heavy metal ions.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of functional materials, and particularly relates to a silicon carbide nanomaterial, a preparation method thereof, and application of the silicon carbide nanomaterial in electrocatalytic detection of heavy metal ions. BACKGROUND

[0002] Chicken manure is an important agricultural organic waste, which contains crude protein, fat, ash, carbohydrates, fiber, nitrogen, phosphorus, potassium, and heavy metal ions such as copper and cadmium, and also contains parasites, insect eggs and bacteria, and can emit odor, attract pests and rodents, and pollute soil and water, and make the soil eutrophication, thereby causing serious pollution to the environment. Therefore, it is of great research significance to convert chicken manure into high-value materials for the comprehensive utilization of agricultural organic waste and environmental protection.

[0003] It has attracted people's research interest to prepare carbon-containing nanomaterials from carbon-containing organic waste such as chicken manure. Nano-silicon carbide is an important high-value carbon-containing nanomaterial, which has high hardness, high temperature resistance, high strength, corrosion resistance, friction resistance, good optical, semiconductor and catalytic properties, and has a wide application in the fields of ceramics, mechanical engineering, refractory materials, semiconductors and catalysis. The national invention patent "Silicon carbide nanomaterial and preparation method thereof" (National invention patent number: ZL201910218578.7) discloses a silicon carbide nanomaterial and a preparation method thereof. The method first dries silicon monoxide and carbon nanotube dispersion liquid to obtain a precursor, and prepares a silicon carbide / carbon nanotube composite under the conditions of a vacuum degree of 0.03-0.1 MPa and a temperature of 1000-1400℃, and then calcines the silicon carbide / carbon nanotube composite under the condition of air or oxygen to obtain a silicon carbide nanobelt. The national invention patent "Preparation method of silicon carbide nanowire" (National invention patent number: ZL200510028034.2) reports a preparation method of silicon carbide nanowire. The method prepares silicon carbide nanowire by mixing hexamethylsilazane, hexamethyldisilane or polydimethylsilane under the protection of inert gas at 1000-1100℃ for 1-3h. The national invention patent "Preparation method of silicon carbide nanowire" (National invention patent number: ZL200810017225.2) reports a preparation method of silicon carbide nanowire. The method prepares silicon carbide nanowire by mixing ferrocene ethanol solution, silicon dioxide, silicon powder and graphite under the protection of argon at 1300-1800℃ for 1-4h. SUMMARY

[0004] In order to overcome the prior art deficiencies, the present application aims to solve the technical problem of providing a silicon carbide nanomaterial and a preparation method thereof, which can be applied to electrocatalytic detection of heavy metal ions, so as to facilitate the control of the preparation process, improve the repeatability, and realize the conversion of agricultural organic waste into treasure.

[0005] The present application is implemented by the following technical solutions.

[0006] The present application provides a silicon carbide nanomaterial, which is composed of silicon carbide nanowires and nanoparticles, the diameter of the nanowires is 30-400 nm, and the length is greater than 10 μm; the silicon carbide is composed of rhombohedral SiC, and is a single crystal structure with the same lattice direction.

[0007] The present application also provides a preparation method of the above-mentioned silicon carbide nanomaterial, which specifically comprises the following steps:

[0008] (1) mixing chicken manure, silicon sol and distilled water, adding them into a sealed container, and keeping the temperature at 80-150 ℃ for 1-5 h, and then drying after cooling to obtain a precursor of chicken manure silicon dioxide;

[0009] (2) mixing the precursor of chicken manure silicon dioxide with calcium chloride and sodium chloride, then loading the mixture into a crucible, and placing the crucible in a vacuum reaction furnace, and keeping the temperature at 800-1000 ℃ for 1-3 h under nitrogen protection;

[0010] (3) after the reaction furnace is naturally cooled to room temperature, adding distilled water to remove calcium chloride and sodium chloride in the sample, and calcining at 500 ℃ for 5 h in an air atmosphere to obtain a silicon carbide nanomaterial.

[0011] The solid content of the silicon sol is 30%; the chicken manure accounts for 20-50% of the weight of the silicon sol; the total weight of the chicken manure and the silicon sol accounts for 20-40% of the weight of the water; the molar ratio of calcium chloride to sodium chloride is 1:1; and the total weight of the chicken manure and the silicon sol accounts for 20-40% of the weight of the calcium chloride and the sodium chloride.

[0012] Further, the chicken manure accounts for 35% of the weight of the silicon sol; the total weight of the chicken manure and the silicon sol accounts for 30% of the weight of the water; and the total weight of the chicken manure and the silicon sol accounts for 30% of the weight of the calcium chloride and the sodium chloride.

[0013] The above-mentioned silicon carbide nanomaterial can be applied to electrocatalytic detection of heavy metal ions as a nanoelectrode material.

[0014] Further, the heavy metal ions are Hg 2+ , Pb 2+ or Cd 2+ .

[0015] The scientific principle of the present application is speculated as follows:

[0016] The present application adopts the above synthesis process, first, under the condition of sealed state, heating treatment at 80-150℃ for 1-5h, to obtain uniform chicken manure silicon dioxide precursor, then the chicken manure silicon dioxide precursor is reacted in molten salt at 800-1000℃ for 1-3h under the protection of inert gas nitrogen, the carbon in the chicken manure silicon dioxide precursor reacts with silicon dioxide to form silicon carbide crystal nucleus, and the silicon carbide nanowire is formed through the oxide assisted growth mechanism, and at the same time, due to the existence of copper, cadmium and other metal elements in the chicken manure, copper, cadmium and other metals also play an important role in the formation of silicon carbide nanowire through the gas-liquid-solid growth mechanism.

[0017] Compared with the prior art, the present application has the following technical effects:

[0018] 1、The present application adopts a two-step synthesis process, the synthesis process is easy to control, has good repeatability, and provides conditions for the practical application of silicon carbide nanomaterials.

[0019] 2、The raw materials used in the present application are chicken manure, silica sol and water, which can convert agricultural organic waste chicken manure into high-value silicon carbide nanomaterials, realizing the transformation of waste into treasure.

[0020] 3、The silicon carbide nanomaterials prepared by the present application have a large number of active sites, good small size effect, nanosurface effect, good chemical and thermal stability, and good electrocatalytic properties. When the heavy metal ion concentration is in the range of 0.01-1000μM(Hg 2+ ), 0.001-100μM(Pb 2+ ) and 0.01-1000μM(Cd 2+ ), the detection limit is as low as 1.18nM(Hg 2+ ), 0.79nM(Pb 2+ ) and 3.26nM(Cd 2+ ) respectively. Thus, as a nanoelectrode material, it has good application prospect in electrocatalytic detection of heavy metal ions. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 X-ray diffraction (XRD) pattern of the silicon carbide nanomaterials synthesized in Example 1;

[0022] According to the JCPDS PDF card, it can be searched that the obtained silicon carbide is composed of rhombohedral SiC (JCPDS card, card number: 65-8103).

[0023] Figure 2 Scanning electron microscope (SEM) image of the silicon carbide nanomaterials synthesized in Example 1;

[0024] As can be seen from the figure, the product consists of silicon carbide nanowires and nanoparticles, with the nanowires having a diameter of 30–400 nm and a length greater than 10 μm.

[0025] Figure 3 Transmission electron microscopy (TEM) image of the silicon carbide nanomaterials synthesized in Example 1. Figure 3 (a) and high-resolution TEM (HRTEM) images ( Figure 3 (b));

[0026] As can be seen from the figure, the product consists of silicon carbide nanowires and nanoparticles, with the nanowires having a diameter of 30–400 nm. Figure 3 (a)), silicon carbide has a single-crystal structure with the same lattice orientation. Figure 3 (b)).

[0027] Figure 4 The silicon carbide nanomaterials synthesized in Example 1 were used as a glassy carbon electrode modification material for the electrochemical detection of different concentrations of Hg in 0.1 MkCl solution. 2+ Pb 2+ and Cd 2+ Square wave voltammograms (SWVs) (test conditions: solution pH 7, deposition potential -1.5V, deposition time 120s, settling time 60s; the inset plot shows the SWV peak current versus Hg). 2+ Pb 2+ and Cd 2+ (Concentration relationship curve);

[0028] from Figure 4 It can be seen that, with Hg 2+ Pb 2+ and Cd 2+ With increasing concentration, the intensity of the SWV peak current increases significantly. The SWV peak current is related to Hg. 2+ Pb 2+ and Cd 2+ The correlation curves between concentrations show that heavy metal ion concentrations in the range of 0.01–1000 μM (Hg) are relatively stable. 2+ ), 0.001–100 μM (Pb) 2+ ) and 0.01–1000 μM (Cd) 2+ Within the range of ), it has a linear relationship with the SWV peak current, and its detection limit is as low as 1.18 nM (Hg). 2+ ), 0.79 nM (Pb 2+ ) and 3.26 nM (Cd 2+ ). Detailed Implementation

[0029] The application will be described in detail below with reference to specific examples, but the application is not limited to the following examples.

[0030] Example 1

[0031] (1) The chicken manure, silica sol and distilled water were mixed, the solid content of the silica sol was 30%, the chicken manure accounted for 20% of the weight of the silica sol, the total weight of the chicken manure and silica sol accounted for 20% of the weight of the water, and the mixture was added into a sealed container, incubated at 80°C for 1 h, and dried after cooling to obtain a precursor of chicken manure silicon dioxide;

[0032] (2) The precursor of chicken manure silicon dioxide was mixed with calcium chloride and sodium chloride, the molar ratio of calcium chloride to sodium chloride was 1:1, the total weight of the chicken manure and silica sol accounted for 20% of the weight of the calcium chloride and sodium chloride, and then the mixture was loaded into a crucible, the crucible was placed in a vacuum reaction furnace, and incubated at a temperature of 800°C for 1 h under nitrogen protection;

[0033] (3) After the reaction furnace was naturally cooled to room temperature, distilled water was added to remove calcium chloride and sodium chloride in the sample, and calcination was performed in an air atmosphere at 500°C for 5 h to obtain a silicon carbide nanomaterial.

[0034] Example 2

[0035] (1) The chicken manure, silica sol and distilled water were mixed, the solid content of the silica sol was 30%, the chicken manure accounted for 50% of the weight of the silica sol, the total weight of the chicken manure and silica sol accounted for 40% of the weight of the water, and the mixture was added into a sealed container, incubated at 150°C for 5 h, and dried after cooling to obtain a precursor of chicken manure silicon dioxide;

[0036] (2) The precursor of chicken manure silicon dioxide was mixed with calcium chloride and sodium chloride, the molar ratio of calcium chloride to sodium chloride was 1:1, the total weight of the chicken manure and silica sol accounted for 40% of the weight of the calcium chloride and sodium chloride, and then the mixture was loaded into a crucible, the crucible was placed in a vacuum reaction furnace, and incubated at a temperature of 1000°C for 3 h under nitrogen protection;

[0037] (3) After the reaction furnace was naturally cooled to room temperature, distilled water was added to remove calcium chloride and sodium chloride in the sample, and calcination was performed in an air atmosphere at 500°C for 5 h to obtain a silicon carbide nanomaterial.

[0038] Example 3

[0039] (1) The chicken manure, silica sol and distilled water were mixed, the solid content of the silica sol was 30%, the chicken manure accounted for 25% of the weight of the silica sol, the total weight of the chicken manure and silica sol accounted for 25% of the weight of the water, and the mixture was added into a sealed container, incubated at 90°C for 2 h, and dried after cooling to obtain a precursor of chicken manure silicon dioxide;

[0040] (2) The precursor of chicken manure silicon dioxide is mixed with calcium chloride and sodium chloride, wherein the molar ratio of calcium chloride to sodium chloride is 1:1, and the total weight of chicken manure and silica sol accounts for 25% of the weight of calcium chloride and sodium chloride. Then the mixture is loaded into a crucible, and the crucible is placed in a vacuum reaction furnace under nitrogen protection at a temperature of 850°C for 1.5h;

[0041] (3) After the reaction furnace is naturally cooled to room temperature, distilled water is added to remove calcium chloride and sodium chloride in the sample, and calcination is performed in an air atmosphere at 500°C for 5h to obtain silicon carbide nanomaterials.

[0042] Example 4

[0043] (1) Chicken manure and silica sol are mixed with distilled water, wherein the solid content of the silica sol is 30%, chicken manure accounts for 30% of the weight of the silica sol, and the total weight of chicken manure and silica sol accounts for 30% of the weight of the water. Add to a sealed container, heat at 100°C for 2.5h, and dry after cooling to obtain a precursor of chicken manure silicon dioxide;

[0044] (2) The precursor of chicken manure silicon dioxide is mixed with calcium chloride and sodium chloride, wherein the molar ratio of calcium chloride to sodium chloride is 1:1, and the total weight of chicken manure and silica sol accounts for 30% of the weight of calcium chloride and sodium chloride. Then the mixture is loaded into a crucible, and the crucible is placed in a vacuum reaction furnace under nitrogen protection at a temperature of 900°C for 2h;

[0045] (3) After the reaction furnace is naturally cooled to room temperature, distilled water is added to remove calcium chloride and sodium chloride in the sample, and calcination is performed in an air atmosphere at 500°C for 5h to obtain silicon carbide nanomaterials.

[0046] Example 5

[0047] (1) Chicken manure and silica sol are mixed with distilled water, wherein the solid content of the silica sol is 30%, chicken manure accounts for 35% of the weight of the silica sol, and the total weight of chicken manure and silica sol accounts for 35% of the weight of the water. Add to a sealed container, heat at 110°C for 3h, and dry after cooling to obtain a precursor of chicken manure silicon dioxide;

[0048] (2) The precursor of chicken manure silicon dioxide is mixed with calcium chloride and sodium chloride, wherein the molar ratio of calcium chloride to sodium chloride is 1:1, and the total weight of chicken manure and silica sol accounts for 35% of the weight of calcium chloride and sodium chloride. Then the mixture is loaded into a crucible, and the crucible is placed in a vacuum reaction furnace under nitrogen protection at a temperature of 950°C for 2.5h;

[0049] (3) After the reaction furnace is naturally cooled to room temperature, distilled water is added to remove calcium chloride and sodium chloride in the sample, and calcination is performed in an air atmosphere at 500°C for 5h to obtain silicon carbide nanomaterials.

[0050] Example 6

[0051] (1) The chicken manure, silica sol and distilled water were mixed, wherein the solid content of the silica sol was 30%, the chicken manure accounted for 40% of the weight of the silica sol, and the total weight of the chicken manure and silica sol accounted for 30% of the weight of the water. The mixture was added to a sealed container, incubated at 120°C for 3.5h, and dried after cooling to obtain a precursor of chicken manure silicon dioxide;

[0052] (2) The precursor of chicken manure silicon dioxide was mixed with calcium chloride and sodium chloride, wherein the molar ratio of calcium chloride to sodium chloride was 1:1, and the total weight of the chicken manure and silica sol accounted for 30% of the weight of the calcium chloride and sodium chloride. Then the mixture was loaded into a crucible, which was placed in a vacuum reaction furnace, and incubated at a temperature of 1000°C for 2.5h under nitrogen protection;

[0053] (3) After the reaction furnace was naturally cooled to room temperature, distilled water was added to remove calcium chloride and sodium chloride in the sample, and calcination was performed in an air atmosphere at 500°C for 5h to obtain silicon carbide nanomaterials.

[0054] Example 7

[0055] (1) The chicken manure, silica sol and distilled water were mixed, wherein the solid content of the silica sol was 30%, the chicken manure accounted for 45% of the weight of the silica sol, and the total weight of the chicken manure and silica sol accounted for 25% of the weight of the water. The mixture was added to a sealed container, incubated at 130°C for 4h, and dried after cooling to obtain a precursor of chicken manure silicon dioxide;

[0056] (2) The precursor of chicken manure silicon dioxide was mixed with calcium chloride and sodium chloride, wherein the molar ratio of calcium chloride to sodium chloride was 1:1, and the total weight of the chicken manure and silica sol accounted for 25% of the weight of the calcium chloride and sodium chloride. Then the mixture was loaded into a crucible, which was placed in a vacuum reaction furnace, and incubated at a temperature of 950°C for 3h under nitrogen protection;

[0057] (3) After the reaction furnace was naturally cooled to room temperature, distilled water was added to remove calcium chloride and sodium chloride in the sample, and calcination was performed in an air atmosphere at 500°C for 5h to obtain silicon carbide nanomaterials.

[0058] Example 8

[0059] (1) The chicken manure, silica sol and distilled water were mixed, wherein the solid content of the silica sol was 30%, the chicken manure accounted for 40% of the weight of the silica sol, and the total weight of the chicken manure and silica sol accounted for 20% of the weight of the water. The mixture was added to a sealed container, incubated at 140°C for 4.5h, and dried after cooling to obtain a precursor of chicken manure silicon dioxide;

[0060] (2) The precursor of chicken manure silicon dioxide is mixed with calcium chloride and sodium chloride, wherein the molar ratio of calcium chloride to sodium chloride is 1:1, and the total weight of chicken manure and silicon sol accounts for 20% of the weight of calcium chloride and sodium chloride. Then the mixture is loaded into a crucible, and the crucible is placed in a vacuum reaction furnace under nitrogen protection at a temperature of 900°C for 2h;

[0061] (3) After the reaction furnace is naturally cooled to room temperature, distilled water is added to remove calcium chloride and sodium chloride in the sample, and calcination is performed in an air atmosphere at 500°C for 5h to obtain silicon carbide nanomaterials.

Claims

1. A method for preparing a silicon carbide nanomaterial, characterized in that It comprises the following steps: (1) mixing chicken manure, silica sol and distilled water, adding into a sealed container, keeping at 80-150℃ for 1-5h, drying after cooling to obtain chicken manure-silicon dioxide precursor; (2) mixing chicken manure-silicon dioxide precursor, calcium chloride and sodium chloride, then loading the mixture into a crucible, placing the crucible into a vacuum reaction furnace, keeping at 800-1000℃ for 1-3h under nitrogen protection; (3) after natural cooling of the reaction furnace to room temperature, adding distilled water to remove calcium chloride and sodium chloride in the sample, calcining at 500℃ for 5h in air atmosphere to obtain silicon carbide nanomaterials; The solid content of the silica sol is 30%; The chicken manure accounts for 20-50% of the weight of the silica sol; The total weight of the chicken manure and silica sol accounts for 20-40% of the weight of water; The molar ratio of calcium chloride to sodium chloride is 1:1; The total weight of the chicken manure and silica sol accounts for 20-40% of the weight of calcium chloride and sodium chloride.

2. The method for preparing silicon carbide nanomaterials as described in claim 1, characterized in that, The chicken manure accounts for 35% of the weight of the silica sol; the total weight of the chicken manure and silica sol accounts for 30% of the weight of water; and the total weight of the chicken manure and silica sol accounts for 30% of the weight of calcium chloride and sodium chloride.

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