Nitrogen-rich microporous carbons for highly selective separation of light hydrocarbons

Abstract

A controllable and facile one-pot method for synthesizing N-doped Activated Carbons (NACs) with a considerable amount of N by using a nitrogen-rich polymer precursor as both the nitrogen source and self-template is reported. The obtained NACs are promising solid adsorbents for light hydrocarbon separations with tunable microstructures. Particularly, NACs with a narrow pore size distribution (ca. 2.6–3.8 nm), high specific surface area (ca. 1628.9–2146.1 m² g⁻¹) and high heteroatom content (ca.3.6 wt%) exhibited excellent hydrocarbon uptake capacities (ca. C2 7.59 mmol g⁻¹ and C3 11.77 mmol g⁻¹). Remarkably, NACs also showed unprecedented C3/C2/C1 separation selectivity (ca. C2/C1 65.7 and C3/C1 501.9) at 298 K and 1.0 bar, which is one of the highest so far reported for benchmark adsorbents, according to the Ideal Adsorbed Solution Theory (IAST). Combined with its simple preparation, high adsorption capacity, and excellent light hydrocarbon selectivity, the sample NAC 700 is a potent and promising solid-state adsorbent for light hydrocarbon separation.