About the surface functionalization of the carbon nanotubes with different geometry with manganese oxide

This study presents a quantum-chemical investigation into the functionalization of carbon nanotubes (CNTs) with manganese oxide (MnO), focusing on the influence of nanotube geometry. Using density functional theory (DFT) calculations at the B3LYP/SDD level, the adsorption of MnO onto both “armchair” (6,6) and “zigzag” (6,0) CNT structures was modelled. The analysis determined the most energetically favorable adsorption sites, evaluated changes in electronic properties, and assessed charge distribution via Mulliken population analysis. The results indicate that for both CNT chiralities, adsorption directly above a carbon atom is the most stable configuration. However, the interaction strength and resulting electronic effects are geometry-dependent. The functionalization significantly alters the CNTs’ band gap, decreasing it for the armchair structure while increasing it for the zigzag type. Furthermore, a reduction in partial atomic charges was observed on both the manganese atom and the adjacent carbon atom of the CNT. These findings, detailing the modulated electronic structure, provide a theoretical foundation for the rational design of advanced composite nanomaterials. Specifically, the controlled changes in electronic properties suggest high potential for developing enhanced and selective gas-sensing applications based on CNT-MnO hybrids.