Carbon nanotube (CNT)-based three-dimensional ordered macroporous (3DOM) carbon material and preparation method thereof

This patent application claims the benefit and priority of Chinese Patent Application No. 202110658668.5, entitled “Carbon nanotube (CNT)-based three-dimensional ordered macroporous (3DOM) carbon material and preparation method thereof” filed on Jun. 11, 2021, the disclosure of which is incorporated by reference herein in its entirety as part of the present application.

The present disclosure relates to a carbon nanotube (CNT)-based three-dimensional ordered macroporous (3DOM) carbon material and a preparation method thereof, belonging to the technical field of carbon materials.

Porous materials are widely used in energy conversion and storage, catalysis, sensing and many other fields due to large specific surface area, high pore volume, and topological properties thereof. In addition to large specific surface area, porous carbon materials have excellent electrical conductivity and structural stability, and thus have become a basis for the construction of various nanocomposites. In recent years, many novel nanoporous carbon materials, such as CNTs, ordered mesoporous carbon, 3DOM carbon, and hierarchical porous carbon, have been successfully prepared and showed excellent use values. In addition to the general characteristics of common porous carbon materials, such as large specific surface area and high electrical conductivity, 3DOM carbon materials have strong periodic pore structure arrangement, uniform pore size, as well as a three-dimensional and ordered overall structure. Therefore, the 3DOM carbon materials have broad prospects for use in the fields of catalyst supports, electrode materials, and adsorption and purification. Controllable synthesis and efficient assembly of nanomaterials are the premise and guarantee for practical use. So far, no literature or patent has reported a nanoporous carbon material with a one-dimensional CNT structure and a 3DOM structure and a preparation method thereof.

An object of the present disclosure is to provide a CNT-based 3DOM carbon material (which is a CNTs aggregation material) and a preparation method thereof. The preparation method has a simple process, is low in cost, and could synthesize a nanoporous carbon material with a one-dimensional CNT structural unit and a 3DOM structure, which has a regular and organized macrostructure.

The present disclosure provides a CNT-based 3DOM carbon material, including a honeycomb network structure having a 3DOM-structure formed by overlapping CNTs, where ordered macropores each have a diameter of 270 nm to 360 nm, and the CNTs each have an outer diameter of 8 nm to 20 nm.

In some embodiments, the carbon material is a composite of carbon and other substances, wherein the carbon refers to pure carbon, and the carbon material is compounded by carbon and nickel.

The present disclosure further provides a method for preparing the CNT-based 3DOM carbon material, including:

step 1, dissolving solid powders of nickel nitrate and citric acid in deionized water to obtain a dissolved solution, stirring the dissolved solution to be uniform to obtain a precursor solution; immersing a template based on regularly-arranged polymethyl methacrylate (PMMA) microspheres in the precursor solution to obtain a template immersed solution, and filtering the template immersed solution under vacuum to obtain a filter cake, and drying the filter cake at ambient temperature to obtain a precursor; and step 2, placing the precursor obtained in step 1 in a tubular furnace, and subjecting the precursor to a calcination for carbonization under atmospheric pressure and in an inert gas, to obtain the CNT-based 3DOM carbon material.

In the present disclosure, during the calcination, PMMA in the precursor is pyrolysed in-situ to obtain a hydrocarbon vapor, which serves as a carbon source for CNT growth.

In some embodiments, a molar ratio of the nickel nitrate to the citric acid is 2:1; and concentrations of the nickel nitrate and the citric acid are adjusted as required, for example, the nickel nitrate has a concentration of 2 mol/L, and the citric acid has a concentration of 1 mol/L.

In some embodiments, the immersing is conducted at ambient temperature for 4 h.

In some embodiments, the inert gas is argon. In some embodiments, the calcination for carbonization is conducted under atmospheric pressure at a calcination temperature of 450° C. to 1,000° C. for 60 min with a heating rate of 10° C./min from ambient temperature to the calcination temperature, followed by conducting natural cooling. In some embodiments, the calcination is conducted at 450° C., 600° C., or 1,000° C. It is found that with an increase of the calcination temperature, a metallic nickel component in the precursor has enhanced crystallinity and a nanoparticle size is increased. In addition, the metallic nickel component is easily removed by etching with an acidic reagent according to requirements for use, to obtain a CNT-based 3DOM carbon material without nickel.

The method according to the present disclosure has the following beneficial effects:

In the present disclosure, in the method for preparing the CNT-based 3DOM carbon material, a nanoporous carbon material with a one-dimensional CNT structure and a 3DOM structure could be obtained through simple operations such as immersing and calcination in an inert gas. The nanoporous carbon material has a three-dimensional bicontinuous honeycomb network structure, with a uniformly-distributed pore size and a highly-organized arrangement. These morphological and structural features provide a basis for subsequent multifunctional use of the material.

The physical properties such as crystal structure, morphology, and chemical composition of the CNT-based 3DOM carbon material are determined using instruments such as a D8-Focus X-ray diffractometer (XRD), a Regulus 8100 scanning electron microscope (SEM), a JEMF200 high-resolution electron transmission electron microscope (TEM), and a LabRam HR Evolution Raman spectrometer (Raman).

In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, a brief introduction to the accompanying drawings required for the embodiments will be provided below.

FIG. 1 A shows an XRD pattern of the CNT-based 3DOM carbon materials prepared under different calcination temperatures in Example 1 to 3; where (I to III) correspond to samples prepared at temperatures of 450° C., 600° C., and 1,000° C., respectively.

FIG. 1 B shows a Raman pattern of the CNT-based 3DOM carbon materials prepared under different calcination temperatures in Example 1 to 3; where (I to III) correspond to samples prepared at temperatures of 450° C., 600° C., and 1,000° C., respectively.

FIGS. 2 A- 2 C show SEM images of the CNT-based 3DOM carbon material prepared at 450° C. in Example 1.

FIGS. 2 D- 2 F show TEM images of the CNT-based 3DOM carbon material prepared at 450° C. in Example 1.

FIG. 2 G shows interlayer spacing of the CNT-based 3DOM carbon material prepared at 450° C. in Example 1.

FIGS. 3 A- 3 C show SEM images of the CNT-based 3DOM carbon material prepared at 600° C. in Example 2.

FIGS. 4 A- 4 B show SEM images of the CNT-based 3DOM carbon material prepared at 1,000° C. in Example 3.

The present disclosure will be further described below in conjunction with specific examples, but the present disclosure is not limited to the following examples.