Pitch-based hyper-cross-linked polymers with high performance for gas adsorption

Abstract

A general challenge will be to reengineer porous materials where scale-up is prohibited by cost, retaining advanced functions but using cheaper and more sustainable building blocks. Every year the petro- and coal-chemical industry produces massive amounts of pitch, mainly composed of phenols, polycyclic aromatic hydrocarbons and heterocyclic compounds. We employed these previously ignored building blocks and prepared hyper-cross-linked polymers (HCPs) with a high surface area via a one-step Friedel–Crafts reaction. Depending on the place of origin, petroleum-pitch-based HCPs have a maximum BET surface area of 1337 m² g⁻¹ with good chemical stability. The inherent heteroatoms in the pitch (sulfur) and the introduced heteroatom (chlorine) endow the obtained HCPs with excellent gas adsorption capability. The uptake capacity for CO₂ reaches up to 17.74 wt% (1.0 bar, 273 K) and the hydrogen storage is up to 1.83 wt% (1.13 bar, 77 K), which is much better than those of most reported microporous organic polymers. In addition, the pitch-based HCPs also show high organic vapor capture capacity at room temperature (cyclohexane: 1115 mg g⁻¹; ethyl acetate: 685 mg g⁻¹; methanol: 1198 mg g⁻¹ and benzene: 890 mg g⁻¹). The effective utilization of pitch for HCPs with high gas adsorption capability is essential for global sustainable development and environmental issues.