Co3O4–SWCNT composites for H2S gas sensor application

Abstract

An arc-discharge method to fabricate Co3O4 nanoparticles and Co3O4-single walled carbon nanotube (SWCNT) nanocomposite structures is developed. The insertion of variable Co content into the graphite tube produced proportionally different compositions of Co nanoparticles in the web of SWCNTs synthesized. The oxidation temperature employed determines the content of SWCNT that remains in the composites as well as the crystallinity of the cobalt oxide nanoparticles. The fabricated Co3O4–SWCNT nanocomposite structures were applied as a gas sensor to detect the H2S gas species with high selectivity among reducing gases including NH3, CH4 and H2. The Co3O4–SWCNTcomposite structure exhibited better performance than a pure Co3O4 nanoparticle structure due to the high defect density in the Co3O4 nanoparticles. In general, films made of nanoparticle agglomerations showed better performance than thin film type sensors, illustrating the nano effect.