Ammonia-treated porous carbon derived from ZIF-8 for enhanced CO2 adsorption

• Published in: Applied surface science 2016-04, Vol.369, p.390-397
• Main Authors: Ma, Xiancheng, Li, Liqing, Wang, Shaobin, Lu, Mingming, Li, Hailong, Ma, Weiwu, Keener, Tim C.
• Format: Article
• Language: English
• Subjects: Adsorption; Ammonia; Ammonia modification; Carbon; Carbon dioxide; CO2; Fourier transforms; Infrared spectroscopy; Porous carbon; Surface chemistry; X-rays; ZIF-8
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2016.01.274

The role of nitrogen species in increasing CO2 adsorption capacity has been explained with the mechanisms of base–acid interaction, as well as hydrogen bonds interaction. •A porous carbon (ZC) was prepared at 900°C using ZIF-8 as a solid template for CO2 adsorption.•The ZC was further treated by ammonia functionalization to improve CO2 uptake.•The detailed interaction mechanism between N-containing groups and CO2 molecules is elucidated. A porous carbon (ZC) was prepared at 900°C using zeolitic imidazolate framework-8 (ZIF-8) as a solid template for CO2 adsorption. The ZC was further treated by ammonia functionalization to improve CO2 uptake. The textural and surface characteristics of ZC samples were determined by X-ray diffraction (XRD), N2 adsorption, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). It was revealed that ammonia treatment at 600°C considerably enhanced the specific surface area and N-content of ZC. However, the pyrrolic-N group was decreased, yet the pyridinic-N group was increased with an increased temperature. The pyrrolic-N significantly enhanced CO2 adsorption. The ammonia treatment, on the one hand, increases the alkalinity of ZC sample and the base–acid interaction between N-containing functional groups with CO2. On the other hand, the ammonia treatment increased pyrrolic-N group (NH) into carbon surface facilitating the hydrogen-bonding interactions between proton of pyrrolic-N and CO2 molecules.