China Carbon Aerogel Research Area Made New Progress
2017-12-18 15:20:01 From: Tradematt-Aerogel
China Aerogel has been hailed as a new material for changing the world. It has a very wide range of applications in civil fields such as high-tech fields such as aerospace and defense as well as civil construction and industrial pipe insulation. Structurally, aerogels are ultra-light porous nanomaterials assembled from three dimensions by zero-dimensional quantum dots, one-dimensional nanowires, or two-dimensional nanosheets. Various variables of low-dimensional nanostructures, such as geometry, size, density, surface topography, chemical properties and other parameters, have a significant impact on the resulting Aerogel properties.
So far, a variety of low-dimensional nanostructures have been assembled into functional Aerogel, but the size of these nanostructured cells is below 100 nanometers, or even only a few nanometers. The preparation of aerogels with a size of more than 100 nanometers (ie, submicron) of the structural units is a huge challenge, mainly due to two reasons. First, the larger the size of the Aerogel structure unit, the smaller the specific surface area (The two are inversely related). For sub-micron structural units, whether it is inorganic (higher density) or organic (lower density), the specific surface area of the obtained Aerogel is very small, thus losing the excellent airgel specific surface area Feature; the second is whether the connection between the nano-scale structural units is a physical effect or a chemical bond, as the size of the structural unit becomes larger, the proportion of atoms in the junction to the total number of atoms sharply decreases, and thus the assembled airgel The material will rapidly become brittle as the size of the structural elements increases.
In response to these challenges, the Aerogel team led by Zhang Xuetong, a researcher at the Suzhou Institute of Nanotechnology and Nanostructures, CAS, and Song Wenhui, a professor at University College London, and Yan Lifeng, a professor at the University of Science and Technology of China, cooperate with conductive polymers with an average diameter of 220 nm Polyaniline polypyrrole copolymer) hollow spheres as precursors, graphene oxide as a cross-linking agent, successively through the sol-gel process, the supercritical fluid extraction process, high temperature heat treatment process and other key steps, successfully obtained a new type of Full carbon aerogels, graphene crosslinked carbon hollow sphere Aerogel. The presence of cross-linking agent graphene cleverly transforms the point-to-point contact between the ball and the ball into point-to-point contact, thereby enhancing the mechanical properties of the resulting Aerogel; the use of hollow-sphere structures, A large number of micropores were made to ensure that the resulting final Aerogel has a large specific surface area. The selection of the precursor conductive polymer enables the final all-carbon Aerogel to achieve nitrogen doping.
The graphene-crosslinked carbon hollow sphere Aerogel obtained in this study has low density (51-67mg / cm3), high conductivity (263-695S / m), high specific surface area (569-609m2 / g) (1.8MPa) and many other advantages, is expected to be widely used in the fields of energy (capture, storage, conversion), sensing, catalysis, adsorption, separation and functional composite materials etc. The work is to assemble large size particles into Aerogel Glue provides a good design idea and solves the technical problem of preparing functional Aerogel from sub-micron structural units.