Highly sensitive H2S sensor based on template-synthesized CuO nanowires

A sensor device featuring massive aligned CuO nanowires has been fabricated for H2S detection. Metallic copper (Cu) nanowires were first synthesized by a template-assisted electrodeposition method. Dielectrophoresis (DEP) and thermal oxidation were then used to assemble and functionalize/oxidize the nanowires. Topology of the CuO nanowires showed rugged surfaces on the nanowires. H2S sensing properties were characterized by conducting experiments with varying influential factors, including concentration levels from 10 to 1000 ppb and working temperatures from 25 to 420 degrees C. The CuO nanowire sensor showed good response and repeatability upon H2S exposure with a detection limit of 2.5 ppb and a linear response ranging from 10 ppb to 100 ppb. In addition, the study of temperature influence revealed that the highest response was achieved at 180 degrees C. Furthermore, with increased working temperature, the CuO nanowire sensor had shorter response and recovery times. An interesting two-stage response was discovered for this CuO nanowire sensor responding to H2S exposure, indicating that two competing reactions existed on the CuO surface.