Electronic, optical, and catalytic properties of finite antimonene nanoribbons: First principles study

Finite antimonene nanoribbons are investigated using density functional theory calculations. Attaching chemical groups, like COOH and OH, to the edges has been successfully attained with negligible deformation and moderate binding energy. They are semiconductors with energy gap a1/42.3 eV that slightly affected by attaching groups such as C2H5 or significantly decreases to 1.8 eV by attaching NO. The optical gaps, from 1.5 eV to 2 eV, are lower than the electronic ones which indicate the existence of excitonic transitions that appear due to the quantum confinement in the finite nanoribbons. Oxygen evolution on the edges shows better catalytic activity than on the surface due to the moderate adsorption of reaction intermediates in the former. Thus, the nanoribbons are preferable for water oxidation than the bulk antimonene. Attaching chemical groups slightly worsen the process due to the stronger adsorption of reaction intermediates. A minimum overpotential of 0.38 V has been achieved in unmodified zigzag-nanoribbons. This value in addition to the appropriate energy gap make antimonene nanoribbons excellent photocatalysts for water splitting.