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

Abstract

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 TiO2 and α-MoO3 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 MoO3 surfaces. Interaction of water molecules was more energy-efficient with anatase surface than with MoO3 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 TiO2 and TiO2:MoO3 composite materials. Predicted low output signal value of the sensors towards CH4, high output value towards hydrogen with its decrease at high MoO3 content in TiO2:MoO3 composite and sufficiently high sensitivity towards ethanol were proved in practice.