Nitrogen doping of porous carbon-supported CuCl(I) for enhanced CO adsorption

Abstract

To investigate the effect of N doping on CO adsorption, N-containing functional groups were introduced into chitosan-based porous carbon via urea treatment. CuCl was subsequently loaded into the resulting porous carbon support using a simple physical mixing method, followed by identifying the optimal loading amount for selective CO adsorption. Elemental analysis, Fourier-transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive spectroscopy were employed to confirm the successful incorporation of N-containing functional groups and CuCl into the porous carbon support. In particular, the N-doped carbon-supported CuCl with a weight ratio of carbon support-to-CuCl of 1:0.8 exhibited a higher CO uptake (3.66 mmol/g) than its non-Ndoped counterpart with a ratio of 1:1 (3.37 mmol/g) at 298 K and 1 bar. Moreover, it exhibited superior CO/ CO2 selectivity and excellent cyclic CO adsorption-desorption stability under mild conditions, which was attributed to a moderate isosteric heat of adsorption ranging from 41 to 51 kJ/mol. Theoretical studies confirmed the enhanced CO/CO2 selectivity of the CuCl clusters on the -NH2 functionalized carbon surface. The results of this study suggest that introducing N-containing functional groups onto porous carbon supports is a promising strategy for enhancing the CO adsorption performance of carbon-supported CuCl.