Efficient design of non-shrinkage xerogels via metal coordination and triazine steric hindrance for activated carbon xerogels with interconnected hierarchical structure

Abstract

Designing xerogels at the molecular level to overcome volume shrinkage is a promising strategy for carbon xerogels with desirable structure and performance. Here, we design a xerogel with non-shrinkage by introducing ZnCl2 into resorcinol-melamine-formaldehyde polymerization. The gel network consisting of micrometer pores and large particles (0.26–1.35 μm) is constructed by the coordination of Zn2+ with oxygen/nitrogen-containing groups, which is attributed to the structural support of the rigid triazine skeleton with large steric hindrance. Therefore, the reinforced gel network possesses enough strength to withstand capillary forces during atmospheric drying, and special drying and solvent exchange are avoided. The xerogels show non-shrinkage and a short preparation time of 24 h. The resulted activated carbon xerogels with interconnected hierarchically micro‑meso-macropores exhibit an optimal specific surface area of 1520 m2/g (through xerogels pyrolysis and the pore-forming of ZnCl2), high adsorption (methylene blue, I–, Cu2+, etc.), and repeated adsorption ability. This work provides novel thought for porous nanomaterials with non-shrinkage and desirable structures in adsorption and energy storage.