Tuned sensitivity towards $H2S$ and $NH3$ with Cu doped barium strontium titanate materials

The different amount of Cu-doped Barium Strontium Titanate (BST) thick film materials have been tested for their gas-sensing performances towards $NH3$ and $H2S$ under dry and 50% relative humidity (RH) background conditions. The optimum $NH3$ sensitivity was attained with 0.1mol% Cu-doped BST whereas the selective detection of $H2S$ was highlighted using 5mol% Cu-doped BST material. No cross-sensitivity effects to CO, $NO2$⁠, $CH4$ and $SO2$ were observed for all tested materials operated at their optimum temperature (200°C) under humid conditions (50% RH). The presence of humidity clearly enhances the gas sensitivity to $NH3$ and $H2S$ detection.