Room temperature SO2 and H2 gas sensing using hydrothermally grown GO–ZnO nanorod composite films

Abstract

Graphene based 2D materials with a surfeit of active sites and advantageously high surface to volume ratio are effectively linked to well established nanostructured semiconducting metal oxides for development of nanocomposites with enhanced gas sensing properties. Graphene Oxide (GO), a sister material of graphene, is therefore a natural choice for development of room temperature operated gas sensors. In the current investigation hydrothermally grown GO and ZnO nanorods composite (GO–ZnO–NR) is utilised for room temperature gas sensing of H2 and SO2 gases. Room temperature detection of H2 and SO2 at sub-100 ppm levels with linear variation in response for different concentrations is demonstrated. Morphological and structural analyses are conducted using Scanning electron microscopy, Raman spectroscopy and X-ray diffraction. GO-ZnO-NR composite sensor is seen to exhibit robust sensing response of 5.82 and 5.45 for 100 ppm each of H2 and SO2 gases respectively at room temperature. Further, the delayed response and recovery times exhibited by the sensor for SO2 gas are recognized to be due to formation of strongly adhering SO3 species.