Efficient construction of low shrinkage xerogels via coordination-catalyzed in-situ polymerization for activated carbon xerogels with multi-dyes adsorption

Obtaining large specific surface areas (SSA) for carbon xerogels poses a significant challenge due to the inevitable volume shrinkage of xerogel. Here, the Zn2+ coordination-catalyzed in-situ polymerization approach was proposed to fabricate xerogels with a low shrinkage of 13.03 % and a short preparation period of 24 ​h. In resorcinol-formaldehyde (RF) polymerization, ZnCl2 could accelerate the reaction kinetics through the coordination of the Zn2+ and hydroxyl groups. The gel network with adjustable RF particles (46.5 nm-1.89 ​μm) and narrow neck structures was constructed by changing ZnCl2 and ethanol contents, which could resist volume shrinkage during atmospheric drying without solvent exchange. The activated carbon xerogels (ACXs) with hierarchical structure were designed by one-step carbonization/activation due to the pore-forming of ZnCl2. The obtained ACXs showed a large SSA of 1689 ​m2/g, multi-dyes adsorption capacity (methylene blue, Congo red, methyl orange, and Sudan III were 625.90, 359.46, 320.69, and 453.92 ​mg/g, respectively), and reusability of 100 %. The maximum monolayer MB adsorption capacity was 630.28 ​mg/g. This work presents an efficient strategy to design porous nanomaterials with low shrinkage and large SSA, which illustrates promising applications in separation, adsorption, and photoelectric catalysis.