Hierarchically Structured Porous Nitrogen-Doped Carbon
for Highly Selective CO<sub>2</sub> Capture
- Publication date
- Publisher
Abstract
Nitrogen-doping has proven to be
an effective strategy for enhancing
the CO<sub>2</sub> adsorption capacity of carbon-based adsorbents.
However, it remains challenging to achieve a high doping level of
nitrogen (N) and a significant porosity in a carbon material simultaneously.
Here we report a facile method that enables the fabrication of ordered
macroporous nitrogen-doped carbon with the content of N as high as
31.06 wt %. Specifically, we used poly(EGDMA-<i>co</i>-MAA)
microspheres as a template to fabricate the structure which can strongly
interact with melamine (the precursor of nitrogen-doped carbon framework),
self-assemble into three-dimensionally ordered structure, and be easily
removed afterward. Upon chemical activation, significant microporosity
is generated in this material without degrading its ordered macroporous
structure, giving rise to a hierarchically structured porous nitrogen-doped
carbon in which a remarkable N content (14.45 wt %) is retained. This
material exhibits a moderate CO<sub>2</sub> adsorption capacity (2.69
mmol g<sup>–1</sup> at 25 °C and 3.82 mmol g<sup>–1</sup> at 0 °C under 1 bar) and an extraordinarily high CO<sub>2</sub>/N<sub>2</sub> selectivity (134), which is determined from the single-component
adsorption isotherms based on the ideal adsorption solution theory
(IAST) method. This value far exceeds the CO<sub>2</sub>/N<sub>2</sub> selectivity of thus-far reported carbon-based adsorbents including
various nitrogen-doped ones. We believe that such an unprecedented
CO<sub>2</sub>/N<sub>2</sub> selectivity is largely associated with
the unusually high N content as well as the partially graphitic framework
of this material