Formaldehyde gas sensing property and mechanism of TiO2–Ag nanocomposite

We report the microstructure and gas-sensing properties of anatase TiO2 doped with Ag nanocomposite prepared by the sol–gel method. In particular, we focus on the effect of Ag dopant on the formaldehyde (H2CO) sensing behavior of TiO2-based sensor. We found that formaldehyde gas response of TiO2 was enhanced evidently by adding Ag. Further investigation based on first principles calculation shows that TiO2–Ag (1 0 1) surface enables high adsorbance of H2CO molecule and receives larger charge from adsorbed gas molecules, which are responsible for the excellent sensing performance observed.