Abstract
The rising concentration of atmospheric CO₂ is a major driver of climate change, necessitating the development of efficient carbon capture technologies. This study quantitatively investigates the surface buildup and multilayer adsorption behavior of CO₂ on activated carbon (AC) using a probabilistic modeling framework in conjunction with adsorption experiments. Key parameters analyzed include the number of adsorption layers, adhesion energy (ΔEa), internal energy (Eint), and void density (DM). Results reveal that CO₂ adsorption on AC forms three to four distinct layers under optimal pressure and temperature conditions, with elevated temperatures reducing the number of layers due to increased interaction energy. The process is characterized as exothermic physisorption (ΔEa: 23.08–23.78 kJ/mol) with no evidence of chemical bonding. Multilayer adsorption effectively compensates for AC’s high density of active sites, thereby enhancing CO₂ capture efficiency. These insights advance the understanding of CO₂ sorption mechanisms on heterogeneous surfaces and guide the design of more thermally stable and efficient carbon capture materials. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1038/s41598-025-22526-w.