Enhanced H2S sensing characteristics of SnO2 nanowires functionalized with CuO

The CuO-functionalized SnO2 nanowire (NW) sensors were fabricated by depositing a slurry containing SnO2 NWs on a polydimethylsiloxane (PDMS)-guided substrate and subsequently dropping Cu nitrate aqueous solution. The CuO coating increased the gas responses to 20 ppm H2S up to ∼74-fold. The Ra/Rg value of the CuO-doped SnO2 NWs to 20 ppm H2S was as high as 809 at 300 °C, while the cross-gas responses to 5 ppm NO2, 100 ppm CO, 200 ppm C2H5OH, and 100 ppm C3H8 were negligibly low (1.5–4.0). Moreover, the 90% response times to H2S were as short as 1–2 s at 300–400 °C. The selective detection of H2S and enhancement of the gas response were attributed to the uniform distribution of the sensitizer (CuO) on the surface of the less agglomerated network of the SnO2 NWs.