Nitrogen doping boosts formaldehyde adsorption in activated carbon fibers

Abstract

Heteroatom doping, especially nitrogen doping, is crucial to improving the adsorption performance and electronic properties of porous carbon materials. Our study delves into the impact of nitrogen doping on the adsorption of formaldehyde (HCHO) on activated carbon fiber (ACF). Nitrogen-containing carbon-forming agent (CFA), which has a s-triazine structure, is a common intumescent flame retardant component. In our study, the CFA not only served as a nitrogen source but also formed a protective carbon layer during heat treatment, thereby achieving uniform nitrogen doping of ACF. By adjusting the amount of CFA, we successfully prepared a series of nitrogen-doped activated carbon fibers (N-ACF) with different nitrogen contents. The HCHO adsorption experiments reveal a linear positive correlation between the total nitrogen content of N-ACFs and the HCHO adsorption capacity. The HCHO adsorption capacity of the prepared N-ACF exceeds that of the original ACF by 33.3%, with a maximum adsorption capacity of 312 mg g⁻¹. Our molecular simulation calculations demonstrate that certain types of nitrogen group, such as pyrrolic-N, exerts a positive effect on HCHO adsorption, whereas not all nitrogen groups exhibit this behavior. These results hold significant implications for the development of high-performance porous carbon materials for air pollution control and other applications.