Titanium-benzene complex as a molecular oxide adsorbent: a first principles approach.

CO, SO, NO, CO, SO, and NO gas sensing properties of Ti-benzene (CHTi) complex are studied with first principles calculations by analyzing change in structural parameters, electronic properties, and charge transfer. Adsorption of all six oxide molecules on CHTi complex is found to be thermodynamically favorable at ambient conditions. The Gibbs free energy-corrected adsorption energy range for oxide molecules is found be 0.6-5.9 eV. The SO transfers maximum charge to Ti metal, i.e., 0.36 (e) as compare to other oxides. The binding energy of Ti atom to benzene ring remains higher even after adsorption of oxide gas molecules. The higher values of HOMO-LUMO gap show that oxide-adsorbed complexes are chemically stable. The ADMP-MD simulations show that all oxide molecules remain adsorbed on Ti-benzene complex during the simulations for the temperature range 300-500 K. The Ti-benzene complex shows considerable gas sensing properties at ambient conditions.