Enhanced Hydrogen Adsorption on Scandium<scp>‐Decorated Cyclocarbon C₁₈</scp>: Density Functional Theory Simulations

ABSTRACT Cyclo[18]carbon is a newly synthesized carbon nano ring and the smallest among the family, consisting of eighteen carbon atoms structured in a cyclic polyyne form. A single Scandium atom linked to the C18 bridge site, having −2.47 eV binding energy, allows the incorporation of seven molecular hydrogens exhibiting an average molecular adsorption energy of −0.29 eV. These predicted an average desorption temperature of 369.5 K, enabling its utilization in fuel cells. The estimated weight percentage of hydrogen for the 7 H 2 adsorbed system is 14.74 wt%, which is higher than most of the scandium‐decorated hydrogen storage materials. This high weight percentage is attributed to the strong hydrogen adsorption capacity of Sc and the relatively lesser carbon atoms in the C18 platform and the stable structure among cyclo‐n‐carbons. The structural and thermal stability of the C18‐Sc platform was confirmed via the estimation of the diffusion energy barrier and molecular dynamics simulations. Based on the calculated binding energy, desorption temperature, and hydrogen weight percentage, we conclude that scandium‐decorated cyclo[18]carbon is a promising candidate for energy storage applications.