Nitrogen‐Doped Carbons From Plum Seed Residues for Efficient CO ₂ Capture and CH ₄ Storage

ABSTRACT

The efficient capture of greenhouse gases such as carbon dioxide (CO ₂ ) and methane (CH ₄ ) is of critical importance due to their substantial contributions to global warming. In this study, novel nitrogen‐doped porous carbons were synthesized from green and red plum ( Prunus domestica ) seeds via melamine‐assisted pyrolysis and systematically compared with nitrogen‐doped carbons derived from commercial activated carbon, graphene nanoplatelets, and multiwalled carbon nanotubes. Textural analyses revealed that the biomass‐derived carbons (NGPAC and NRPAC) exhibit exceptionally high surface areas (1759.9 and 1548.7 m ² /g, respectively) and micropore‐dominated structures further enriched by nitrogen functionalities. Gas adsorption measurements at 298 K demonstrated that NGPAC and NRPAC achieved the highest CO ₂ uptakes (3.9 mmol/g) and superior CH ₄ capacities (1.37 and 1.15 mmol/g, respectively), significantly outperforming both commercial carbons (NAC) and nanocarbon‐based materials (NNT and NGR). Adsorption isotherm analyses indicated that the Langmuir and Freundlich models best described the equilibrium data, highlighting favorable adsorption on heterogeneous microporous surfaces. Kinetic studies showed that the pseudo‐first‐order model most accurately captured the adsorption behavior, with bio‐derived carbons displaying rapid uptake rates attributable to their accessible micropores and surface heteroatoms. Overall, these findings demonstrate that plum seed‐derived N‐doped carbons are highly efficient, sustainable, and low‐cost adsorbents for CO ₂ and CH ₄ capture. This work not only valorizes an underutilized agricultural byproduct as a promising precursor for advanced carbon materials, but also provides new insights into the role of precursor type and nitrogen functionalities in tailoring gas adsorption performance.