One-pot synthesis of nitrogen-doped carbons with hierarchically micro- and mesoporous structures for supercapacitors and CO2 capture

Abstract

Nitrogen-doped mesoporous carbons are considered promising candidates for supercapacitors and CO₂ sorbents. However, synthesis of mesoporous carbons usually requires expensive soft or hard templates. In this study, we demonstrate that cost-effective nitrogen-doped carbons can be synthesized through a one-pot method by using tetraethoxysilane (TEOS), triethylamine (TEA) and tetraethylammonium hydroxide (TEAOH) as the precursors. The in situ formed silica derived from TEOS serves as a hard template while TEA and TEAOH are the carbon and nitrogen sources. By removing the hard template, mesoporous carbons are generated. It was found that the carbon (TUD-700) carbonized at 700 °C has the largest pore volume (1.18 cm³ g⁻¹) and the largest surface area (1050 m² g⁻¹). The specific capacitance of TUD-700 can reach 360 F g⁻¹ in the three-electrode system. The energy density and the power density of the assembled symmetric supercapacitor can reach 30.4 W h kg⁻¹ and 455.1 kW kg⁻¹, respectively. TUD-700 and TUD-600 were also used as a tetraethylenepentamine (TEPA) support to prepare “molecular basket” solid amine sorbents to capture CO₂. The CO₂ uptake of 50A/TUD-700 can reach 3.53 mmol g⁻¹. The TUD-700 based solid sorbents show better CO₂ capture performance than TUD-600 based sorbents due to the larger surface area and the larger pore volume.