Water-Ionic Liquid Binary Mixture Tailored Resorcinol-Formaldehyde Carbon Aerogels without Added Catalyst

Abstract

The potential applications of mesoporous carbon aerogels are wide-ranging. These gels are often obtained from resorcinol-formaldehyde (RF) hydrogel precursors. The sol-gel method in this synthesis provides an efficient and versatile means of product control through systematic variation of process conditions, such as pH, stoichiometry, concentration, catalyst, further additives, etc., in addition to the drying and pyrolytic conditions. Here, a novel means of tuning the texture of carbon aerogels is proposed. Water-1-ethyl-3-methylimidazolium ethyl sulfate ([emim][EtSO4] mixtures constitutes a polycondensation medium that requires no added catalyst, thus yielding an intrinsically metal-free carbon aerogel after pyrolysis. We also show that the carbon morphology is tailored by the supramolecular structure of the aqueous ionic liquid. The results of scanning electron micrographs, low-temperature nitrogen adsorption/desorption isotherms, and small-angle X-ray scattering (SAXS) confirm that changing the initial water concentration from 9 to 55 wt % gives rise to systematic alteration of the mesopore size and volume, as well as of the bead size. The pore structure becomes consolidated only when the water content exceeds 25 wt %. When the water content reaches 55 wt %, the bead size increases by two orders of magnitude. The electrocatalytic performance, however, is compromised, most probably by structural defects.

Lightweight and Flexible Phenolic Aerogels with Three-Dimensional Foam Reinforcement for Acoustic and Thermal Insulation

“…Aerogels are low-density solid materials which have continuous porosity and a nanometer network composed of interconnected colloidal-like particles. − Due to their unique structure, aerogels have been widely used as thermal insulators, , environmental treatments, , catalytic carriers, , and acoustic insulations. , Generally, aerogels can be classified into inorganic and organic aerogels, with inorganic aerogels usually being fabricated by hydrolysis and condensation of metal alkoxides, while organic aerogels are usually fabricated from organic precursors such as resorcinol–formaldehyde, melamine–formaldehyde, polyimide, and so forth. Compared to inorganic aerogels, organic aerogels could combine the inherent advantages of aerogels with the conveniences of plastics of flexibility, strength, and safety to fit multifunctional manufacturing processes and uses .…”

Study on Degradation of Benzothiazolium-Based Ionic Liquids by UV-H2O2

“…Ionic liquids (ILs) are considered to be good substitutes for organic solvents with low vapor pressure and low flammability [1] and are widely used in various fields [2,3]. However, their toxicity has been paid more attention in recent years [4,5].…”