Open Access

ARTICLE

Surface Modification of Activated Carbon by Nitrogen Doping and KOH Activation for Enhanced Carbon Dioxide Adsorption Performance

Thanattha Chobsilp¹, Alongkot Treetong², Visittapong Yordsri³, Mattana Santasnachok^4,5, Pollawat Charoeythornkhajhornchai⁶, Jaruvit Sukkasem⁷, Winadda Wongwiriyapan⁸, Worawut Muangrat^1,5,*

1 Department of Advanced Materials Engineering, Faculty of Engineering, Burapha University, Chonburi, 20131, Thailand
2 National Nanotechnology Center, Pathumthani, 12120, Thailand
3 National Metal and Materials Technology Center, Pathumthani, 12120, Thailand
4 Department of Chemical Engineering, Faculty of Engineering, Burapha University, Chonburi, 20131, Thailand
5 Interdisciplinary Center of Robotics Technology (ICRT), Faculty of Engineering, Burapha University, Chonburi, 20131, Thailand
6 Department of Chemical Engineering, Faculty of Engineering, Srinakharinwirot University, Nakhonnayok, 26120, Thailand
7FILTER MATCH Co., Ltd., Bangkok, 10520, Thailand
8 College of Materials Innovation and Technology, King Mongkut’s Institute of Technology Ladkrabang, Bangkok, 10520, Thailand

* Corresponding Author: Worawut Muangrat. Email:

Journal of Renewable Materials 2025, 13(11), 2155-2168. https://doi.org/10.32604/jrm.2025.02025-0111

Received 12 June 2025; Accepted 25 September 2025; Issue published 24 November 2025

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°C–900°C. Likewise, the mixture of potassium hydroxide (KOH) and AC was heated at 800°C, followed by heat treatment under NH₃ gas at 800°C (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°C to 800°C. However, the nitrogen content of N-AC decreased to 3.40 at% after using NH₃ heat treatment at 900°C. 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.

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Supplementary Material

Supplementary Material File

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