Glass-Like Carbon Spheres — Activation, Porosity and Application Possibilities

Abstract

ABSTRACT:A brief review on spherical carbons, including fullerenes and related spherical particles, is first provided, followed by a review of the results on air activation, porosity and applications focused on glass-like carbon spheres derived from phenolic resin spheres. Kinetic studies of the oxidation in air provide a fundamental understanding of activation process of glass-like carbon spheres. On the basis of the results, a new activation procedure, viz. two-step activation, is proposed, which provides ca. 10% higher oxidation yield in obtaining a comparative pore structure. Some possibilities for applications of these glass-like carbon spheres are also described, such as the adsorption/desorption of CO 2 gas and chlorinated methanes, the adsorption of organic molecules from their aqueous solutions, and the provision of electrodes for electric double layer capacitors and lithium ion rechargeable batteries.

An Efficient Way To Introduce Hierarchical Structure into Biomass-Based Hydrothermal Carbonaceous Materials

“…While in flowing air, the carbonaceous materials suffer from complete decomposition at high temperatures. For example, to activate glassy carbonaceous spheres made from resorcinol–formaldehyde, the temperature should be limited to under 450 °C with a long activating time (e.g., 72 h) . However, the developed porosity is mainly composed of micropores.…”

A simple approach to spherical nickel-carbon monoliths as light-weight microwave absorbers

“…The second method is the self-assembly approach. [28][29][30][31][32][33][34] This mainly includes two steps, the polymerization of carbon precursors under heat treatment and the decomposition of the template during a carbonization process. The precursors used in this method, like carbohydrates, polysaccharides, lignocellulose sources, [28][29][30] pitches, 31 phenolic resins 32 and organic polymers, 33 are usually viscous and therefore are difficult for inorganic ions to be homogeneously mixed to achieve final monoliths with uniformly inserted metal nanoparticles for better properties.…”

Design and Fabrication of Hierarchically Porous Carbon with a Template-free Method

“…We proposed here the new activation process in static air at 900°C. Air was reported to adjust the surface functional groups of HTC materials 33 or activate carbonaceous materials under low temperatures with long reaction time 34 , while no examples of activation process by air were presented at such high temperature, which may due to the complete decomposition of the carbonaceous material. According to our experimental data, the activation yield in static air at 900°C is around 23%, comparable to that by KOH activation at 600°C (27%) ( Table S2 ).…”