Molecular dynamics simulation as a tool for prediction of the properties of TiO2 and TiO2:MoO3 based chemical gas sensors

Fast and simple molecular dynamics simulation method was used to investigate the interaction of water, hydrogen, methane, and ethanol molecules with {100} set atomic planes of anatase TiO 2 and α-MoO 3 at 300 K and 573 K. Preliminary molecular simulation of gas molecules interaction with oxide surface provides an opportunity to eliminate empirical search of the oxide material with preassigned gas sensing properties. Facilities of molecular dynamics simulation approach without involving time-consuming quantum chemical calculations turn to be sufficient for this purpose. From the molecular simulation results it followed, that the most energy-efficient interaction of hydrogen molecules turned to be with (001) anatase plane. The less energy-efficient and localized among all the investigated processes was the interaction of methane molecules both with anatase and MoO 3 surfaces. Interaction of water molecules was more energy-efficient with anatase surface than with MoO 3 surface. Molecular dynamics simulation results were confronted with experimental results on gas sensing properties of one-electrode thermocatalytic chemical gas sensors on the basis of anatase TiO 2 and TiO 2 :MoO 3 composite materials. Predicted low output signal value of the sensors towards CH 4 , high output value towards hydrogen with its decrease at high MoO 3 content in TiO 2 :MoO 3 composite and sufficiently high sensitivity towards ethanol were proved in practice. • At TiO 2 surface H 2 molecules tend to localize over the Ti-ions chains between O-ions. • Interaction of CH 4 molecule is inefficient and nonlocalized both with TiO 2 and MoO 3 . • H 2 O interaction is more energy-efficient with anatase surface than with MoO 3 surface. • Predicted on simulation gas sensing properties were proved in practice. • Material with preassigned gas sensing properties can be found by molecular simulation.