Ultralight covalent organic framework/graphene aerogels with hierarchical porosity

Abstract

The fabrication of macroscopic objects from covalent organic frameworks (COFs) is challenging but of great significance to fully exploit their chemical functionality and porosity. Herein, COF/reduced graphene oxide (rGO) aerogels synthesized by a hydrothermal approach are presented. The COFs grow in situ along the surface of the 2D graphene sheets, which are stacked in a 3D fashion, forming an ultralight aerogel with a hierarchical porous structure after freeze-drying, which can be compressed and expanded several times without breaking. The COF/rGO aerogels show excellent absorption capacity (uptake of >200 g organic solvent/g aerogel), which can be used for removal of various organic liquids from water. Moreover, as active material of supercapacitor devices, the aerogel delivers a high capacitance of 269 F g−1 at 0.5 A g−1 and cycling stability over 5000 cycles.

Hierarchical Interface Engineering for Advanced Nanocellulosic Hybrid Aerogels with High Compressibility and Multifunctionality

“…ii) For porosity, a hierarchical layout of pores at several length scales is generated in the developed aerogels, which provide space to reduce thermal conductivity and buffer the compress/release deformation. [8] iii) For interfaces, building blocks should be connected strongly to keep structural integrity, which are crosslinked tightly for proper load transfer and impeding crack opening in the entire deformation process. [7] The combination of these three factors has successfully inspired researchers to design and fabricate high-performance aerogels.…”

Marriage of 2D Covalent–Organic Framework and 3D Network as Stable Solar‐Thermal Still for Efficient Solar Steam Generation

“…Covalent–organic frameworks (COFs) are emerging as a class of crystalline porous polymers based on earth abundant elements and have been demonstrated to have promising applications in catalysis, gas adsorption, energy storage, and sensing. [ 28–31 ] One significant advantage of COFs is that their properties can be modulated at atomic/molecular level by introducing of functional monomers or peripheral residual functional groups. In this field, 2D COFs comprising extended π‐systems or well‐defined donor–acceptor heterojunctions in nm‐sized regimes have been shown to be promising candidates for optoelectronic applications.…”

Design of a Waste Paper‐Derived Chemically ‘Reactive’ and Durable Functional Material with Tailorable Mechanical Property Following an Ambient and Sustainable Chemical Approach

“…In the past, mechanically durable materials have been fabricated extensively for various prospective energy and health related applications. [1][2][3] The strategic integration of carbon nanotubes, [4,5] graphene derivatives, [6][7][8] cellulose nanocrystals, [9] etc. impart the required mechanical durability for practical applications.…”

“…Li et al, developed ultralight, compressible covalent organic framework aerogel reinforced with reduced graphene oxide which exhibits excellent absorption and electrochemical properties. [7] Wang et al, fabricated highly compressible boron nitride nanotubes aerogel reinforced with reduced graphene oxide with superior mechanical property which was impossible to attain without the reinforcement. [8] Apart from the commonly used nanomaterials, [10][11][12] different other approaches [13][14][15][16][17][18][19] -including association of elastomers, MXenes, electrodeposited nano-alloys etc.…”