Abstract
Acetaldehyde gas sensing using hybrids of reduced graphene oxide (rGO) and transition metal elements, rGO-M (M = oxide/hydroxide of Mn, Fe, Co and Ni) has been investigated. Thin films of GO, rGO and rGO-M on conductive glass were deposited through simple and affordable techniques and characterized using Raman spectroscopy, powder X-ray diffraction patterns, field emission scanning electron microscopy and electrical conductivity measurements. Concentration dependent resistances during the oxidation of acetaldehyde gas in air (10 to 50%) were investigated by using a sensing probe devised from rGO, GO-M and the rGO-M hybrids, of which rGO-Ni exhibited the maximum sensitivity. In rGO-Ni, in combination with rGO the NiOOH precursor can capture electrons (generated from acetaldehyde oxidation) through the holes, while indicating rGO-Ni to be a p-type semiconductor. This report implies the possibility of developing inexpensive graphene based p-type semiconductors for sensing other gases as well.