CuO/V2O5 hybrid nanowires for highly sensitive and selective H2S gas sensor

Vanadium pentoxide (V2O5) nanowires decorated with CuO nanoparticles on their surface have been prepared by a facile chemical route. The gas-sensing performance of the CuO/V2O5 nanohybrids has been examined against H2S, CO, and NO2 gases over a range of gas concentrations from 7 to 60 ppm and working temperatures from 100 to 400 degrees C, and compared with that of pristine V2O5 nanowires without the decoration. The CuO/V2O5 nanohybrids exhibit a greatly enhanced sensitivity toward H2S gas selectively and are relatively indifferent to CO and NO2 gases. The gas-sensing response of the nanohybrids increases by nearly 18 times (from 1.84 to 31.86) when tested against 23 ppm of H2S gas at 220 degrees C. The nanohybrids remain stable when detecting H2S gas for a period of two weeks. This selective enhancement is attributable to the local p-n junction formed at the interface together with the reversible chemical reaction that occurs when CuO is exposed to H2S gas at the temperature employed.