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Surface Modification of Activated Carbon by Nitrogen Doping and KOH Activation for Enhanced Carbon Dioxide Adsorption Performance
Author(s)
Chobsilp, Thanattha
Treetong, Alongkot
Yordsri, Visittapong
Santasnachok, Mattana
Charoeythornkhajhornchai, Pollawat
Sukkasem, Jaruvit
Muangrat, Worawut
Date Issued
January 1, 2025
Type
Article
Abstract
Nitrogen-doped activated carbon (N-AC) was successfully prepared by KOH-activation and nitrogen doping using ammonia (NH3) heat treatment. Coconut shell-derived activated carbon (AC) was heat-treated under NH3 gas in the temperature range of 700℃–900℃. Likewise, the mixture of potassium hydroxide (KOH) and AC was heated at 800℃, followed by heat treatment under NH3 gas at 800℃ (hereafter referred to as KOH-N-AC800). Scanning electron microscopy (SEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) method were utilized to analyze morphology, crystallinity, chemical bonding, chemical composition and surface area. The surface area and porosity of N-AC increased with increasing NH3 heat treatment. Similarly, the nitrogen content in the N-AC increased from 3.23% to 4.84 at% when the NH3 heat treatment was raised from 700℃ to 800℃. However, the nitrogen content of N-AC decreased to 3.40 at% after using NH3 heat treatment at 900℃. The nitrogen content of KOH-N-AC800 is 5.43 at%. KOH-N-AC800 and N-AC800 exhibited improvements of 33.66% and 26.24%, respectively, in CO2 adsorption compared with AC. The enhancement of CO2 adsorption of KOH-N-AC800 is attributed to the synergic effect of the nitrogen doping, high surface area, and porosity. The results exhibited that nitrogen sites on the surface play a more significant role in CO2 adsorption than surface area and porosity. This work proposes the potential synergistic effect of KOH-activation and nitrogen doping for enhancing the CO2 adsorption capacity of activated carbon.
Citation
Journal of Renewable Materials, 13(11), 2155-2168, 2025