Volatile organic compounds sensing by Li/Ti doped ethylene complex

Abstract

First principles calculations and atom centered density matrix propagation (ADMP) molecular dynamics (MD) simulations are performed to study the adsorption of small volatile organic compounds (VOCs) like HCHO, CH4, CHF3 and CH3OH on Li/Ti metal doped ethylene complex (C2H4M, M = Li, Ti). The sensitivity of C2H4M complex upon VOCs adsorption is examined through change in structural parameters and electronic properties of a complex. The NBO charge analysis is carried out to measure charge transfer during adsorption process. The interaction between VOCs and C2H4M complex is analysed in detail with the help of PDOS plot and frontier molecular orbital analysis. Effect of VOCs adsorption on binding energy of Li/Ti metal atom to C2H4 substrate in C2H4M complex is also studied. The operating temperature and pressure of sensor is determined by calculating temperature and pressure dependent Gibbs free energy corrected adsorption energies and confirmed through ADMP–MD simulations. Quantum mechanical stability of VOCs adsorbed complexes is confirmed by vibrational frequency analysis. This study suggests potential application of C2H4M complex as a VOC gas sensing material for HCHO, CH4, CHF3 and CH3OH compounds.