Carbon Material-Based Aerogels for Gas Adsorption: Fabrication, Structure Design, Functional Tailoring, and Applications

Abstract

Carbon material-based aerogels (CMBAs) have three-dimensional porous structure, high specific surface area, low density, high thermal stability, good electric conductivity, and abundant surface-active sites, and, therefore, have shown great application potential in energy storage, environmental remediation, electrochemical catalysis, biomedicine, analytical science, electronic devices, and others. In this work, we present recent progress on the fabrication, structural design, functional tailoring, and gas adsorption applications of CMBAs, which are prepared by precursor materials, such as polymer-derived carbon, carbon nanotubes, carbon nanofibers, graphene, graphene-like carbides, fullerenes, and carbon dots. To achieve this aim, first we introduce the fabrication methods of various aerogels, and, then, discuss the strategies for regulating the structures of CMBAs by adjusting the porosity and periodicity. In addition, the hybridization of CMBAs with other nanomaterials for enhanced properties and functions is demonstrated and discussed through presenting the synthesis processes of various CMBAs. After that, the adsorption performances and mechanisms of functional CMBAs towards CO₂, CO, H₂S, H₂, and organic gases are analyzed in detail. Finally, we provide our own viewpoints on the possible development directions and prospects of this promising research topic. We believe this work is valuable for readers to understand the synthesis methods and functional tailoring of CMBAs, and, meanwhile, to promote the applications of CMBAs in environmental analysis and safety monitoring of harmful gases.

Keywords: aerogels; carbon materials; functional tailoring; gas adsorption; hybrid materials.

Figure 1

Fabrication of aerogels: (a) Freezing-mediated growth and freeze-drying fabrication of SNF aerogels. Reprinted with permission from Ref. [20], Copyright 2020, Wiley VCH. (b) Electrospinning and freeze-drying promoted fabrication of CNF/GO hybrid aerogels. Reprinted with permission from Ref. [21], Copyright 2019, Elsevier.

Figure 2

Structural tailoring of aerogels. (a–c) Porosity adjusting of aerogels via particle growth with different acidic feeding rate: (a) slow, (b) fast, and (c) optimized. Reprinted with permission from Ref. [32], Copyright 2019, MDPI. (d–g) Periodicity adjusting of cellulose nanocrystal (CNC) aerogels: (d) synthesis method, (e) CNC suspension without and with crossed polarizers, (f) CNC aerogels with cylindrical shape, and (g) polarized optical microscopy image of aerogels. Reprinted with permission from Ref. [34], Copyright 2018, Royal Society of Chemistry.

Figure 3

Fabrication of carbon aerogels: (a) Powdery carbon aerogels. Reprinted with permission from Ref. [41], Copyright 2017, Elsevier Ltd. (b,c) 2D titanium carbide and bacterial cellulose-derived carbon aerogels. (b) fabrication process and (c) SEM image of the carbon aerogels. Reprinted with permission from Ref. [43], Copyright 2019, American Chemical Society.

Figure 4

Fabrication of CNT-based aerogels: (a) PVA-based nanoparticles (PNP)/CNTs aerogels. Reprinted with permission from Ref. [47], Copyright 2020, Elsevier Ltd., (b,c) Hollow CNT aerogels: (b) synthesis process and (c) photograph and microscopy characterizations. Reprinted with permission from Ref. [6], Copyright 2019, Wiley VCH.

Figure 5

Fabrication of CNF-based aerogels: (a) BC nanofiber-based fabrication of CNF aerogels. Reprinted with permission from Ref. [56], Copyright 2020, Wiley VCH. (b) Electrospinning, freeze drying, and carbonization-based formation of CNF aerogels. Reprinted with permission from Ref. [59], Copyright 2020, Royal Society of Chemistry.

Figure 6

Fabrication of graphene-based aerogels: (a) GA@Ni hybrid aerogels. Reprinted with permission from Ref. [27], Copyright 2019, Elsevier Ltd. (b) 3D printing-created GAs with periodic macropores. Reprinted with permission from Ref. [63], Copyright 2016, American Chemical Society.

Figure 7

Fabrication of carbide-based aerogels: (a) SiC aerogels. Reprinted with permission from Ref. [67], Copyright 2019, Elsevier Ltd. (b) TiC and NbC aerogels. Reprinted with permission from Ref. [68], Copyright 2015, Royal Society of Chemistry.

Figure 8

Carbon material-based aerogels for the adsorption of CO₂ and CO. (a,b) MgAl-MMO/rGO hybrid aerogels for the adsorption of CO₂: (a) synthesis process, and (b) adsorption and desorption of CO₂. Reprinted with permission from Ref. [83], Copyright 2020, Wiley VCH. (c,d) 3D Ru/GA-MOF aerogel for the adsorption and catalysis of CO: (c) fabrication of Ru/GA-HK aerogels, and (d) reaction mechanism for CO removal. Reprinted with permission from Ref. [85], Copyright 2018, Wiley VCH.

Figure 9

Carbon-based aerogels for the adsorption of H₂S. (a,b) CNT/CNF-M²⁺ hybrid aerogels for the adsorption of H₂S and other gases: (a) synthesis process and (b) adsorption and removal mechanism. Reprinted with permission from Ref. [89], Copyright 2021, Elsevier Ltd. (c,d) 3D SnO₂/CA for the adsorption of H₂S: (c) synthesis process, and (d) reaction mechanism. Reprinted with permission from Ref. [90], Copyright 2019, Elsevier Ltd.

Figure 10

CMBAs for the adsorption of H₂. (a–d) Pt-modified CAs for the adsorption of H₂: (a) synthesis methods, (b) SEM image, (c) TEM image, and (d) adsorption reaction. Reprinted with permission from Ref. [94], Copyright 2016, Elsevier Ltd. (e,i) shell-core MgH₂@CA microspheres for the adsorption of H₂: (e) synthesis method, (f) SEM image, (g) adsorption capacity, (h) recyclability, and (i) adsorption and desorption at different temperatures. Reprinted with permission from Ref. [96], Copyright 2018, Elsevier Ltd.

Figure 11

CMBAs for organic gas adsorption. (a–c) graphene aerogels for the adsorption of formaldehyde: (a) Photograph of rGO-hBN hybrid aerogels, (b) adsorption configuration of formaldehyde on rGO, and (c) adsorption reaction mechanism. Printed with permission from Ref. [99], Copyright 2021, Nature Publishing Group. (d,e) 3D porous CAs for the adsorption of toluene: (d) fabrication of CAs and the adsorption mechanism, and (e) SEM image of CAs, the inset is optical photo of CAs. Reproduced with permission form Ref. [103], Copyright 2021, Elsevier Ltd.