Influence of CuO catalyst in the nanoscale range on SnO2 surface for H2S gas sensing applications

摘要

The dispersal of CuO catalyst on the surface of the semiconducting SnO2 film is found to be of vital importance for improving the sensitivity and the response speed of a SnO2 gas sensor for H2S gas detection. Ultra-thin CuO islands (8 nm thin and 0.6 mm diameter) prepared by evaporating Cu through a mesh and subsequent oxidation yield a fast response speed and recovery. Ultimately nanoparticles of Cu (average size = 15 nm) prepared by a chemical technique using a reverse micelle method involving the reduction of Cu(NO3)2 by NaBH4 exhibited significant improvement in the gas sensing characteristics of SnO2 films. A fast response speed of a?? 14 s and a recovery time of a?? 60 s for trace level a?? 20 ppm H2S gas detection have been recorded. The sensor operating temperature (130?°C) is low and the sensitivity (e?‘? = 2.06 ?— 103) is high. It is found that the spreading over of CuO catalyst in the nanoscale range on the surface of SnO2 allows effective removal of excess adsorbed oxygen from the uncovered SnO2 surface due to spill over of hydrogen dissociated from the H2S-CuO interaction.