One-Pot Preparation and CO₂ Adsorption Modeling of Porous Carbon, Metal Oxide, and Hybrid Beads

Hierarchically porous carbon (C), metal oxide (ZrTi), or carbon-metal oxide (CZrTi) hybrid beads are synthesized in one pot through the in situ self-assembly of Pluronic F127, titanium and zirconium propoxides, and polyacrylonitrile (PAN). Upon contact with water, a precipitation of PAN from the liquid phase occurs concurrently with polymerization and phase separation of the inorganic precursors. The C, ZrTi, and CZrTi materials have similar morphologies but different surface chemistries. The adsorption of carbon dioxide by each material has been studied and modeled using the Langmuir-Freundlich equation, generating parameters that are used to calculate the surface affinity distributions. The Langmuir, Freundlich, Tóth, and Temkin models were also applied but gave inferior fits, indicating that the adsorption occurred on an inhomogeneous surface reaching a maximum capacity as available surface sites became saturated. The carbon beads have higher surface affinity for CO2 than the hybrid and metal oxide materials.