One-step fabrication of N-doped activated carbon by NH3 activation coupled with air oxidation for supercapacitor and CO2 capture applications

Abstract

In this paper, we reported a simple and effective strategy to prepare N-doped activated carbon for supercapacitor electrodes and CO2 capture. The activation and nitrogen functionalization of the carbonaceous material (pine sawdust) are realized in one step by NH3 activation coupled with air treatment. The role of air oxidant in the NH3 activation process is also discussed. The characterization results show that the nitrogen content of the activated carbon is increased by NH3 activation coupled with air oxidation. More defect sites and larger pore volume are also observed by Raman and BET analysis. The specific capacitance of PS-NA-800 prepared by NH3/air treatment reaches 241 F/g at current density of 0.2 A/g, which is 23% higher than that of PS-N-800 without adding air oxidant. Furthermore, the optimal N-doped activated carbon shows the CO2 adsorption capacity of 4.86 mmol/g at 273 K and 3.62 mmol/g at 298 K. This work reveals that NH3 activation coupled with air oxidation is a highly effective method for N-doped activated carbon preparation. Meanwhile, the activated carbon derived from this method reported in this study also presents the application potential in the energy storage and the sorbent of greenhouse gas.