Preparation of Mesoporous Boron-Doped Porous Carbon Derived from Coffee Grounds via Hybrid Activation for Carbon Capture and Storage

The increasing concentration of carbon dioxide (CO₂) in the atmosphere necessitates the development of efficient carbon capture and storage (CCS) technologies. Among these, adsorption-based methods using porous carbon (PC) have attracted considerable attention due to their low energy requirements and cost-effectiveness. Biomass waste-derived porous carbon is particularly attractive as a sustainable alternative, offering environmental benefits and high-value applications with low costs. In this study, coffee grounds (CGs) were selected as a precursor due to their abundance and cost-effectiveness compared with other biomass wastes. To improve the pore characteristics of CG-derived carbon (CCG), boric acid treatment was applied during carbonization followed by steam activation to prepare boron-doped CG-derived porous carbon (B-PCG). The N₂/77K adsorption–desorption isotherms revealed a significant increase in the specific surface area and total pore volume of B-PCG from 1590 m²/g and 0.71 cm³/g to 2060 m²/g and 1.01 cm³/g, respectively, compared with PCG. Furthermore, high pressure CO₂ adsorption analysis at 298 K up to 50 bar showed an approximately 50% improvement in CO₂ adsorption capacity for B-PCG compared with PCG. These results suggest that boron doping is an effective strategy to optimize the pore structure and adsorption performance of biomass-derived porous carbon materials for CCS application.