Adsorption of carbonyl sulfide on Pt-doped vacancy-defected SWCNT: A DFT study.

• Pt-decorated defected carbon nanotubes show very favorable COS adsorption energies. • Bonding order analysis suggests COS chemisorption mainly through C and S atoms. • Charge density shows a significant electronic transfer from surface to COS molecule. • Density of states confirms the strong interaction between COS and Pt-doped nanotube. Carbonyl sulfide (COS) is a dangerous gas produced from fossil fuel combustion and petrochemical procedures, so proper adsorbent and sensors are required for removal and detection. In this work, we study by Density Functional Theory methods the COS adsorption on a Pt-decorated vacancy-defected carbon nanotube, in order to evaluate the potential of this nanostructure as gas adsorbent or sensing material. First, we analyze the most stable configuration for Pt adsorption on the defective nanotube, obtaining a more favorable binding energy for a symmetric structure with equivalent C Pt bonds. Next, several configurations are studied for COS adsorption on the Pt-doped nanotube. In the most stable systems, the adsorbate interacts with the Pt decoration through its C and S atoms, with adsorption energy values of about −2.7 eV. Overlap population and bonding order studies are also performed, showing a strong affinity between COS and the Pt-doped surface. Furthermore, an important electronic transfer from nanotube to the gas molecule was detected, which would indicate chemical adsorption. Density of states analysis also show a considerable stabilization of COS molecule after adsorption. Our study suggests that a Pt-doped carbon surface could act as a promising adsorbent and chemical sensor for COS gas removal or detection purposes. [ABSTRACT FROM AUTHOR]