Ultrahigh Surface Area Nanoporous Carbons Synthesized via Hypergolic and Activation Reactions for Enhanced CO2 Capacity and Volumetric Energy Density

Abstract

We report a family of carbon sorbents synthesized by integrating hypergolics with activation reactions on a templated substrate. The materials design leads to nanoporous carbons with a BET area of 4800 m² g^–1 with an impressive total pore volume of 2.7 cm³ g^–1. To the best of our knowledge, this BET area value is the highest reported in the literature. Electron spin resonance (ESR) measurements determined the number of radicals in an effort to provide a mechanistic understanding of the formation of ultrahigh surface area carbons. In combination with XPS, we propose a mechanism based on the synergistic effect between rim-based pentagonal rings and carbon radicals, which we believe can be exploited to produce other highly porous carbons. The CO₂ capture capacity of the hyperporous carbon tested under dynamic CO₂ capture conditions was ∼1.25 mmol g^–1 versus 0.66 mmol g^–1 of a conventionally activated carbon under similar conditions. The CO₂ capture kinetics were extremely fast and reached 99% of the total capacity within 120 s. Lastly, supercapacitor electrodes deliver a high volumetric energy density of ∼60 W h L^–1 and a volumetric power density of 1 kW L^–1, which is the highest reported value for activated carbon.