Highly sensitive H2S sensor based on template-synthesized CuOnanowires

Abstract

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 °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 °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.