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

CO, SO, NO, CO₂, SO₂, and NO₂ gas sensing properties of Ti-benzene (C₆H₆Ti) 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 C₆H₆Ti 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 SO₂ 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.