First principles investigation on selective hydrogen sensing properties of α-phase TeO2.

α-phase TeO 2 is a promising sensing material because of its unique ability to detect hydrogen gas. To investigate atomic-level mechanism on gas sensing of TeO 2 , the interaction between H 2 , NH 3 , SO 2 , CO 2 , H 2 S, CH 4 gases and TeO 2 are studied via first principles simulations. By the calculated adsorption energy, radial distribution function, band gap and charge transfer, TeO 2 shows a superior selective detection performance to hydrogen and it is consistent with experimental conclusion. The H–H bond of H 2 break after adsorption and a new H–O bond with length of 0.98 Å forms between TeO 2 and H 2. Moreover, the adsorption of H 2 causes an obvious increasing of DOS near the Fermi level, indicating a clear change in the electric conductivity. The calculated self-diffusion coefficients show that the diffusion of hydrogen molecule in TeO 2 is much easier than the other gases, suggesting a fast response of H 2 by TeO 2. This work provides a theoretical foundation for analysis and design of TeO 2 -based hydrogen sensor. Image 1 • For the first time, atomic sensing mechanism of TeO 2 towards H 2 gas is studied. • Predicted gases sensing behaviours of TeO 2 consist with experiments. • Detection of H 2 is related to formation of O–H bonds between H 2 and TeO 2. • Our analysis provides a basis for designing of TeO 2 -based gas sensor. [ABSTRACT FROM AUTHOR]