Oxamic acid potassium salt as a novel and bifunctional activator for the preparation of N-doped carbonaceous CO2 adsorbents

Abstract

N-doped porous carbons have shown great potential as CO2 adsorbents. In the current work, we proposed the use of oxamic acid potassium salt (OAPS) as a novel and bifunctional activator for direct synthesis of N-doped porous carbon. OAPS served as both chemical activator and nitrogen source at the same time. N-doped carbons were prepared from different biomass materials including cellulose, agar, and glucose. The yielded carbons exhibited micropores dominated porous structure. Effects of activation conditions and biomass types on the carbons’ physicochemical properties were thoroughly studied. As a result, the carbons showed high specific surface area (733–2438 m2/g) and nitrogen content (1.51–3.92 wt%). The presence of narrow micropores and doped nitrogen qualified OAPS activated carbons as efficient CO2 adsorbents. These carbons demonstrated high CO2 uptake of 3.91 mmol/g at 25 °C and 1 bar. Respective effects of narrow micropores and N-doping on CO2 adsorption were also analyzed and revealed. The current study indicated that OAPS could be used as a very convenient and versatile activator for the preparation of N-doped carbonaceous CO2 adsorbents.