Preparation of Fe3O4-Fe3C Heterostructure Nanosheets / N-Doped C Nanosheets and Their Photocatalytic Applications

Abstract

The present invention relates to the preparation of Fe3O4-Fe3C heterostructure nanosheets / N-doped C nanosheets and their photocatalytic applications. Specifically, Fe2O3 nanosheets, tris(hydroxymethyl)aminomethane, and dopamine hydrochloride are mixed and dried, and then ground and thermally reacted with melamine to obtain Fe3O4-Fe3C heterostructure nanosheets / N-doped C nanosheets; the application of the Fe3O4-Fe3C heterostructure nanosheets / N-doped C nanosheets in photocatalytic reactions.

Description

Technical Field

[0001] The present invention relates to the preparation and photocatalytic application of Fe3O4-Fe3C heterostructure nanosheets / N-doped C nanosheets, and belongs to the field of material preparation and application. Background Art

[0002] Dye wastewater is an important factor affecting water resources. Therefore, it is an inevitable requirement for development to search for new technologies that are efficient and green. In recent years, it has been found that by using solar energy to generate free radicals, the decomposition of pollutants can be effectively achieved. Solar photocatalysis is a current research hotspot due to its advantages such as being green and pollution-free. Therefore, Fe3O4-Fe3C heterostructure nanosheets / N-doped C nanosheets are prepared by using heterojunction engineering, which can effectively photocatalyze dye wastewater.

[0003] Although bulk iron oxide has photocatalytic ability, its activity is weak. By changing the kinetic process, preparing and regulating the surface structure and electron arrangement of iron oxide, the change of the semiconductor bandgap is realized, and then the photocatalytic degradation efficiency is improved. For example: Gao et al. synthesized Al-doped Fe3O4@Fe2O3 nanoparticles, Zn-doped Fe3O4@Fe2O3 nanoparticles, Cu-doped Fe3O4@Fe2O3 nanoparticles and Mn-doped Fe3O4@Fe2O3 nanoparticles by sol-gel method. Due to the doping of heteroatoms, core-shell structure, etc., they showed higher activity than Fe3O4@Fe2O3 nanoparticles in the photocatalytic degradation reaction of methyl orange (Ceramics International, 2020, 46, 19038-19045). Xu et al. used the NaBH4 reduction method to construct a novel magnetic g-C3N4 / α-Fe2O3 / Fe3O4 composite catalyst from g-C3N4, Fe3O4, FeCl3·9H2O, etc., which showed high activity in the photocatalytic reaction of orange II (RSC Advances, 2018, 8, 5180-5188). Yang et al. synthesized α-Fe2O3 / TiO2 hierarchical heterostructures and Fe3O4 / TiO2 hierarchical heterostructures, and found that the Fe3O4 / TiO2 hierarchical heterostructure in the photocatalytic 2·10 -5It shows high catalytic activity and recyclability in a rhodamine B solution of [[mol / L]] (New Journal Of Chemistry, 2011, 35, 1795 - 1802). Roy et al. synthesized Fe3O4@Fe2O3 / Al2O3 nanocatalysts using FeSO4, FeCl3, Al2O3, etc., which showed high activity in the photocatalytic Cr(VI) reduction reaction and still maintained high efficiency after being recycled 4 times (Chemical Engineering Journal, 2017, 308, 59 - 66). There are many methods for preparing composite materials. By thermal decomposition, Fe3O4 - Fe3C heterostructure nanosheets / N - doped C nanosheets are constructed, and the formation mechanism is further explored for the efficient and stable photocatalytic degradation of dye wastewater.

[0004] Compared with traditional technologies, the photocatalytic technology can effectively utilize solar energy. By constructing a semiconductor of Fe3O4 - Fe3C heterostructure nanosheets / N - doped C nanosheets, it promotes the absorption of light and realizes sewage purification, which has important practical significance. Summary of the Invention

[0005] The present invention aims to provide the preparation of Fe3O4 - Fe3C heterostructure nanosheets / N - doped C nanosheets and their photocatalytic applications.

[0006] Based on the above - mentioned purpose, the technical solutions involved in the present invention are as follows:

[0007] (1) Preparation of Fe3O4 - Fe3C heterostructure nanosheets / N - doped C nanosheets: Disperse 30 mg - 40 mg of Fe2O3 nanosheets (JCPDS#36 - 0664) with a particle size of 20 - 40 nm, 120 - 140 mg of tris(hydroxymethyl)aminomethane, and 50 - 60 mg of dopamine hydrochloride into 50 mL of ethanol and 50 mL of water. After drying, it is ground and mixed with 150 - 200 mg of melamine, and heated at 500 - 550 °C for 0.5 - 1 h in an Ar atmosphere to obtain Fe3O4 - Fe3C heterostructure nanosheets encapsulated by N - doped C nanosheets, that is, Fe3O4 - Fe3C heterostructure nanosheets / N - doped C nanosheets. In the above - mentioned preparation method, the particle size of the Fe3O4 - Fe3C heterostructure nanosheets in the Fe3O4 - Fe3C heterostructure nanosheets / N - doped C is 20 - 60 nm, the Fe3O4 crystal phase belongs to the standard card JCPDS#19 - 0629, and the Fe3C crystal phase belongs to the standard card JCPDS#35 - 0772.

[0008] (2) Application of the Fe3O4-Fe3C heterostructure nanosheets / N-doped C nanosheets prepared by the above preparation method in photocatalytic reaction; when the concentration of methylene blue is 0.01 - 0.1 mg / L, the photocatalytic reaction is carried out for 2 - 4 h, and the removal rate is 100%.

[0009] The present invention has the following advantages:

[0010] 1) Using Fe2O3 nanosheets, tris(hydroxymethyl)aminomethane, and dopamine hydrochloride, Fe3O4-Fe3C heterostructure nanosheets / N-doped C nanosheets were prepared, and a new synthesis route for Fe3O4-Fe3C heterostructure nanosheets / N-doped C nanosheets was developed.

[0011] 2) Fe3O4-Fe3C heterostructure nanosheets / N-doped C nanosheets can effectively photocatalyze methylene blue solution. Description of the Drawings

[0012] Figure 1 are the XRD and TEM characterization results of Fe3O4-Fe3C heterostructure nanosheets / N-doped C nanosheets. Detailed Embodiments

[0013] The following examples are used to further illustrate the present invention, but do not limit the present invention thereby.

[0014] Example 1

[0015] Preparation of Fe3O4-Fe3C heterostructure nanosheets / N-doped C nanosheets: 30 mg of Fe2O3 nanosheets with a particle size of 20 - 40 nm (JCPDS#36-0664), 120 mg of tris(hydroxymethyl)aminomethane, and 50 mg of dopamine hydrochloride were dispersed in 50 mL of ethanol and 50 mL of water. After drying, it was ground and mixed with 150 mg of melamine, and heated at 500 °C for 0.5 h in an Ar atmosphere to obtain Fe3O4-Fe3C heterostructure nanosheets encapsulated with N-doped C nanosheets, that is, Fe3O4-Fe3C heterostructure nanosheets / N-doped C nanosheets. In the above preparation method, the particle size of the Fe3O4-Fe3C heterostructure nanosheets in the Fe3O4-Fe3C heterostructure nanosheets / N-doped C nanosheets is 20 - 60 nm, the Fe3O4 crystal phase belongs to the standard card JCPDS#19-0629, and the Fe3C crystal phase belongs to the standard card JCPDS#35-0772. When the Fe3O4-Fe3C heterostructure nanosheets / N-doped C nanosheets were used in the photocatalytic degradation of wastewater dye, when the concentration of methylene blue was 0.01 mg / L, the reaction was carried out for 2 h, and the removal rate was 100%.

[0016] Example 2

[0017] Preparation of Fe3O4-Fe3C heterostructure nanosheets / N-doped C nanosheets: 40 mg of Fe2O3 nanosheets with a particle size of 20-40 nm (JCPDS#36-0664), 140 mg of tris(hydroxymethyl)aminomethane, and 60 mg of dopamine hydrochloride were dispersed in 50 mL of ethanol and 50 mL of water. After drying, it was ground and mixed with 200 mg of melamine and heated at 550 °C for 1 h in an Ar atmosphere to obtain Fe3O4-Fe3C heterostructure nanosheets encapsulated by N-doped C nanosheets, namely Fe3O4-Fe3C heterostructure nanosheets / N-doped C nanosheets. In the above preparation method, the particle size of the Fe3O4-Fe3C heterostructure nanosheets in the Fe3O4-Fe3C heterostructure nanosheets / N-doped C nanosheets is 20-60 nm, the Fe3O4 crystal phase belongs to the standard card JCPDS#19-0629, and the Fe3C crystal phase belongs to the standard card JCPDS#35-0772. When the Fe3O4-Fe3C heterostructure nanosheets / N-doped C nanosheets were used for photocatalytic degradation of wastewater dye, the reaction was carried out for 4 h when the concentration of methylene blue was 1 mg / L, and the removal rate was 100%.

[0018] Example 3

[0019] Preparation of Fe3O

Claims

1. Preparation method of Fe3O4-Fe3C heterostructure nanosheets / N-doped C nanosheets, characterized in that The following steps are involved: 30 mg-40 mg of Fe2O3 nanosheets, 120-140 mg of tris(hydroxymethyl)aminomethane, and 50-60 mg of dopamine hydrochloride were dispersed in 50 mL of ethanol and 50 mL of water. After drying, the mixture was ground with 150-200 mg of melamine and incubated at 500-550 °C in an Ar atmosphere. o C for 0.5-1 h to obtain Fe3O4-Fe3C heterostructure nanosheets encapsulated by N-doped C nanosheets, namely Fe3O4-Fe3C heterostructure nanosheets / N-doped C nanosheets.

2. The preparation method according to claim 1, characterized in that, The particle size of the Fe2O3 nanosheets is 20-40 nm, and the Fe2O3 nanosheet crystal phase belongs to the standard card JCPDS#36-0664.

3. The preparation method according to claim 1, wherein The obtained Fe3O4-Fe3C heterostructured nanosheets / N-doped C nanosheets encapsulate N-doped C nanosheets encapsulating Fe3O4-Fe3C heterostructured nanosheets, the particle size of the Fe3O4-Fe3C heterostructured nanosheets is 20-60 nm, the Fe3O4 crystal phase belongs to the standard card JCPDS#19-0629, and the Fe3C crystal phase belongs to the standard card JCPDS#35-0772.

4. Use of Fe3O4-Fe3C heterostructured nanosheets / N-doped C nanosheets prepared by the preparation method of any one of claims 1-3 in a photocatalytic reaction; when the methylene blue concentration is 0.01-1 mg / L and the photocatalytic reaction is carried out for 2-4 hours, the removal rate is 100%.

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