Photothermal Assisted Activation of Porous Carbon Materials, Their Preparation Methods and Applications

Abstract

This invention discloses a method for photothermal-assisted activation of carbonaceous materials using sunlight or artificial light sources, enabling the construction of porous structures in these materials and their application in fields such as supercapacitors, secondary ion batteries, and nanocatalysis. It relates to technical fields such as photothermal activation, battery energy, and environmental remediation. The carbonaceous materials primarily include activated carbon, biomass carbon, porous carbon, mesoporous carbon, graphene oxide, graphynylene, carbon nanotubes, and fullerenes (C60), with forms including powder, blocks, sponges, gels, and films. The porous structure can be achieved by photothermal chemical activation of the carbonaceous materials using sunlight, solar simulators, and other light sources, according to design requirements, to construct the internal pore structure. This invention enables various carbonaceous materials to achieve a transformation in porous characteristics, giving them high porosity, high specific surface area, and high energy storage properties, significantly improving double-layer energy storage, ion transport, and mass transport capabilities.

Description

Technical Field

[0001] This invention belongs to the field of materials preparation technology, specifically relating to a porous carbonaceous material prepared by photo-assisted activation processing, its preparation method, and its application. Background Technology

[0002] Supercapacitors are characterized by high power density and, compared to traditional batteries, offer faster charge / discharge rates and longer cycle life, making them widely used in various applications such as electronic communications, electric vehicles, renewable energy storage, and portable electronic products. Based on their energy storage mechanisms, supercapacitors are broadly classified into double-layer capacitors (EDLCs) and Faraday pseudocapacitors (PCs). EDLCs store charge by adsorbing ions onto the electrode surface immersed in an electrolyte, forming an electric double layer. EDLC electrode materials are primarily various types of carbon materials, such as biomass carbon, carbon nanotubes, and graphene. High specific surface area, suitable pore structure, and good conductivity are key to achieving double-layer energy storage.

[0003] To construct carbonaceous materials with high specific surface area and suitable pore size, and to improve the performance of energy storage electrodes, activation is an essential process. However, conventional methods for preparing carbonaceous materials all require high-temperature activation, which leads to high energy consumption and pollution. With the development of the trend towards efficient use of clean energy, finding a simpler, more efficient, lower-cost, and less energy-intensive activation method has become an urgent need.

[0004] In 2011, Professor Rodney S. Ruoff published an article in Science on the application of activated graphene in supercapacitors (Y. Zhu, S. Murali, M.D. Stoller, K.J. Ganesh, W. Cai, P.J. Ferreira, A. Pirkle, R.M. Wallace, K.A. Cychosz, M. Thommes, D. Su, E.A. Stach, R.S. Ruoff, Science 2011, 332, 1537). The authors primarily used microwave treatment of graphene oxide, followed by activation with the strong alkali potassium hydroxide at 800℃ to obtain activated porous graphene materials with ultra-high specific surface area, achieving good supercapacitor performance. This work provides a reference for the activation of nano-carbon materials, but it is still based on the traditional high-temperature thermal treatment activation process.

[0005] Patent CN 116332176 A discloses a method for preparing mesoporous carbon materials with high specific surface area. Porous carbon materials are prepared using the vapor-phase exfoliation activation-in-situ template effect of metal oxalate. The innovation of this patent lies in the addition of metal salts, but it still does not avoid processes such as hydrothermal reactions, and the problem of high energy consumption remains.

[0006] Patent CN 115697902 A discloses a method for manufacturing activated carbon. This patent describes a method that uses a pretreated carbon aggregate precursor reacted with CO2 for high-temperature activation, solving problems such as stability and efficiency in the activation of conventional carbon materials. The entire activation process is an optimization of the traditional activation process, which still requires a high-temperature heat treatment.

[0007] Patent CN 116726877 A discloses a method for preparing porous carbon from biomass. It mainly involves ball milling biomass, trithiocyanate, acidic alumina microspheres, potassium carbonate microspheres, and ammonium permanganate, followed by calcination at 250-350℃, and then high-temperature carbonization at approximately 900℃ to obtain porous carbon.

[0008] This patent addresses the high energy consumption problem in the activation process of carbonaceous materials by proposing a photo-assisted activation method to construct porous carbonaceous materials, providing a low-energy, readily available, and low-cost method for activating carbonaceous materials and its applications. Summary of the Invention

[0009] To address the shortcomings of existing technologies, this invention provides a method for preparing porous carbonaceous materials using photo-assisted activation processing, along with its applications. The method involves treating biomass carbon, porous carbon, and carbon nanomaterials such as graphene, graphylene, carbon nanotubes, and C60 using photo-assisted activation. The localized photothermal effect of light synergistically enhances the etching process of the carbonaceous materials with the chemical reagents, ultimately resulting in a porous structure. Porous carbonaceous materials prepared by photo-assisted chemical activation exhibit abundant mesoporous structures, significantly enhancing ion transport capacity, increasing specific surface area and active sites, greatly improving electrochemical energy storage characteristics, and demonstrating excellent cycle stability. Porous carbonaceous materials prepared using photo-activation possess rich pore structures and good electrical conductivity, making them suitable for applications such as electrode materials in supercapacitors and secondary batteries.

[0010] This invention is achieved through the following technical solution:

[0011] A method for preparing photothermally activated porous carbon materials is characterized by using a light source to irradiate carbon materials containing activators, so that the localized photothermal effect of light and the carbon materials and chemical reagents synergistically enhance each other, resulting in thermal field, energy transfer, decomposition and etching processes, causing some carbon atom skeletons to decompose or fall off, forming a porous structure.

[0012] The light sources include sunlight, a sunlight simulator, light-emitting diodes (LEDs) of different wavelengths, xenon lamps, mercury lamps, and other light sources.

[0013] Furthermore, the specific steps of this preparation method are as follows:

[0014] After the carbonaceous material and activator are mixed evenly, they are dried at low temperature and then placed in a chamber filled with inert gas or under vacuum. The relative position of the carbonaceous material and the light source is adjusted so that the light is focused on the surface of the carbonaceous material or defocused appropriately.

[0015] Photoactivation preparation is carried out by setting the light irradiation power. Under the action of light irradiation, the interaction between carbonaceous materials and chemical activators is enhanced. Under the action of photon energy, a local thermal field is generated, and the carbonaceous materials are etched off to form a porous structure.

[0016] Another objective of this invention is to provide an application of carbonaceous materials with porous structures prepared by photo-assisted activation in supercapacitors, secondary ion batteries, photoelectrocatalysis, and adsorption.

[0017] Compared with the prior art, the advantages of the present invention are as follows:

[0018] (1) Activating carbon materials such as graphene by using light-assisted methods can utilize the interaction between light, carbon and activator to generate light field localization, causing carbon materials to undergo etching, decomposition and other phenomena, forming a large number of micropores. It has the advantages of low energy consumption and non-contact, and the process is simple and low cost.

[0019] (2) Photo-activated carbonaceous materials have loose and porous characteristics, and the pore structure has hierarchical porous characteristics, which significantly increases the specific surface area of ​​the material, optimizes the internal microstructure, and helps to enhance the properties of energy storage, active sites and ion transport.

[0020] (3) Photo-assisted activated carbonaceous materials are highly adaptable and can be processed and prepared according to actual needs for application in fields such as supercapacitors, secondary batteries, and photoelectrocatalysis.

[0021] (4) This invention utilizes the interaction between light and carbon materials and activators to generate photothermal chemical effects, thereby constructing a porous structure inside the carbon material and realizing the activated porous structure of the carbon material. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a preparation process for preparing porous carbonaceous materials using photo-assisted chemical activation according to the present invention.

[0023] Figure 2 This image shows electron microscope (EM) images of porous graphene prepared using a photo-assisted chemical activation method according to the present invention. The left image is a scanning electron microscope (SEM) image of the photoactivated porous carbon material (graphene); the right image is a transmission electron microscope (TEM) image of the photoactivated porous carbon material (graphene), showing a clearly visible porous structure.

[0024] Figure 3This is a Raman spectrum image of a porous carbonaceous material (graphene) prepared by a photo-assisted chemical activation method according to the present invention.

[0025] Figure 4 The nitrogen adsorption-desorption curves and pore size distribution of a porous carbonaceous material (graphene) prepared by a photo-assisted chemical activation method according to the present invention are shown.

[0026] Figure 5 This invention relates to the performance of a porous carbonaceous material (graphene) prepared by a photo-assisted chemical activation method in supercapacitor energy storage.

[0027] Figure 6 The present invention relates to the cycling stability of a porous carbonaceous material (graphene) prepared by a photo-assisted chemical activation method in an energy storage device. Detailed Implementation

[0028] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0029] Example 1

[0030] The light source used in this invention can be sunlight, xenon lamps, mercury lamps, and various other light sources. The carbon materials include, but are not limited to, biomass carbon, porous carbon, and carbon materials such as graphene, graphyne, carbon nanotubes, and C60. The forms include, but are not limited to, powders, sponges, gels, and films. Among them, biomass carbon refers to carbon materials prepared using biomass, such as plant straw and fruit shells, and includes, but is not limited to, porous carbon, mesoporous carbon, coal, and activated carbon.

[0031] A method for preparing porous graphene using a photo-assisted activation method for porous carbonaceous materials, comprising the following specific steps:

[0032] Porous graphene was obtained using a xenon lamp-assisted chemical activation technique: Graphene material was uniformly mixed with a certain amount of activator solution and dried at low temperature in a mold to prepare a 30 mm diameter disc; then, it was placed in a vacuum chamber or an inert gas chamber. The relative position of the graphene material surface and the xenon lamp source was adjusted, and the light spot was positioned on the area to be processed using a convex lens or Fresnel lens. The energy density of the light source irradiation was adjusted to 2 kWm³. -2 The graphene material is uniformly irradiated for a certain period of time or scanned stepwise along a specific path. After irradiation, the graphene material absorbs energy under photo-assisted chemistry and interacts with chemical activators, resulting in the direct etching or shedding of some carbon, forming porous graphene. Compared with traditional high-temperature heat treatment activation methods, photo-assisted activation can also achieve a porous structure with a high specific surface area, but its energy consumption is much lower than that of traditional high-temperature activation processes.

[0033] Figure 1 This is a schematic diagram of the preparation process of the present invention. As can be seen from the figure, the preparation process is simple and does not require complex processing technology. Figure 2 The left image is a scanning electron microscope (SEM) image of porous graphene aerogel prepared by photo-assisted chemical activation. Figure 2 The image on the right is a transmission electron microscope (TEM) image of porous graphene aerogel prepared by photo-assisted chemical activation, clearly showing a large number of pore structures; Figure 3 It can be seen that after photoactivation, the characteristic signals of graphene are enhanced, and the 2D peak is significantly enhanced; from Figure 4 It can be seen that the pore structure of carbonaceous materials changes significantly after photo-assisted activation. The adsorption-desorption curve (left figure) shows a clear hysteresis loop, indicating the generation of a large number of mesopores, which is significantly different from before activation. The pore size distribution curve in the right figure also shows that the photo-activation process has a good effect, and the pore structure is more abundant.

[0034] Application Example 1

[0035] An application of porous graphene prepared using a photo-assisted activation method for porous carbonaceous materials in supercapacitors is disclosed. Specifically, the photo-activated porous graphene material is mixed with a conductive agent, PVDF solution, etc., and then pressed with nickel foam current collector to form an electrode sheet. The electrode sheet is placed in a round beaker containing KOH solution; a three-electrode system is used, with Pt as the counter electrode and a calomel electrode as the reference electrode, to test its capacitance performance. The principle of this invention is to utilize the photo-assisted activation to induce changes such as etching or shedding of carbon materials, forming a rich micro-nano porous structure transformation, significantly increasing the specific surface area and improving conductivity. Graphene materials with rich porous structures are beneficial for enhancing ion reaction and exchange rates, significantly improving capacitor performance. Figure 5 and 6 The image shows the supercapacitor properties of porous graphene materials prepared by photoactivation.

[0036] The principle of this invention is to utilize the thermochemical interaction between light, graphene, and chemical reagents to generate a localized thermal field and enhance the etching process, forming a large number of porous structures, especially mesoporous structures. The porous graphene structure enhances ion propagation pathways, increases energy storage sites, and significantly improves electrochemical energy storage characteristics.

[0037] The present invention discloses a method for preparing photoactivated porous graphene. This method utilizes various light sources, such as sunlight, xenon lamps, mercury lamps, and others, to activate carbon materials (including but not limited to biomass carbon, porous carbon, graphene, graphynylene, carbon nanotubes, C60, etc., in forms including but not limited to powder, block, sponge, gel, film, etc.) to obtain carbon materials with a loose porous structure. The prepared porous carbon materials exhibit good effects in enhancing ion transport, realizing supercapacitors, secondary batteries, and environmental purification, and can achieve applications including but not limited to electrochemical energy storage and catalytic degradation. In one application example, the photoactivated porous graphene was used as an electrode active material to design an alkaline supercapacitor system applicable to electrochemical energy storage. The photoactivated porous graphene significantly enhances electron or ion transport performance and increases specific surface area, improving the capacitance performance of the raw material by more than 70%.

[0038] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0039] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0040] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for preparing photothermally activated porous carbon materials, characterized in that, By irradiating carbonaceous materials containing activators with a light source, the localized photothermal effect of light and the carbon materials and chemical reagents synergistically enhance the photothermal chemical activation effect. Under the drive of the photothermal field, thermal field, energy transfer, decomposition and etching processes occur, causing some carbon atom skeletons to decompose or fall off, forming a porous structure. The light source includes sunlight, LED, xenon lamp, or mercury lamp, with an energy density of 0.01-1000 kWm. -2 ; The steps include the following: After mixing carbonaceous material with an activator, the mixture is placed on a substrate. The relative position of the carbonaceous material and the light source, as well as the light intensity parameters, are adjusted to focus the light onto the surface of the carbonaceous material. By uniformly irradiating for a certain period of time or scanning step by step along a certain path, carbonaceous materials are etched, decomposed, or detached under photo-assisted activation, forming a large number of porous structures, thus realizing the activation process of carbonaceous materials under photo-assisted activation. The porous carbonaceous material has a hierarchical porous structure and includes mesoporous features.

2. The method for preparing photothermal-assisted activated porous carbonaceous materials according to claim 1, wherein the carbonaceous materials include porous carbon and graphene, graphyne, carbon nanotubes or C60, and the morphology includes powder, block, and film.

3. The method for preparing photothermal-assisted activated porous carbonaceous materials according to claim 1, wherein the carbonaceous material morphology includes a sponge.

4. The method for preparing photothermal-assisted activated porous carbonaceous materials according to claim 1, wherein the carbonaceous material morphology includes gel.

5. The method for preparing photothermal-assisted activated porous carbonaceous materials according to claim 1, characterized in that, Set the power of the light source from 0.01 kW to 1000 kW, as well as the scanning path and time, and focus the light on the material surface or at a certain distance from the surface.

6. A photothermal-assisted activated porous carbonaceous material, characterized in that, The porous carbon material is prepared by photothermal-assisted activation according to any one of claims 1-5. The porous carbon material has a hierarchical porous structure and includes mesoporous features.

7. The application of the photothermal-assisted activated porous carbonaceous material as described in claim 6 in a supercapacitor.

8. The application of the photothermal-assisted activated porous carbonaceous material as described in claim 6 in the catalytic degradation of organic dyes.

9. The application of the photothermal-assisted activated porous carbonaceous material as described in claim 6 in an energy storage battery.

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