Catalytic Effect of Copper Oxide on H2S Sensing Properties of Nanostructured WO3

Cuprous oxide powder was added to WO3 sol as a catalyst and the composite sol was deposited on alumina substrates by spin coating process and annealing at 500 degrees C for 1 hour. Sensing properties of the pure and doped tungsten oxide samples to H2S gas were analyzed. WO3-Cu2O (1%) samples showed good sensitivity towards 250 ppb of the gas at 100 degrees C and 1 ppm at room temperature (25 degrees C). Crystal structure, morphology and chemical composition of the sample were studied by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDAX) analyses and X-ray photoelectron spectroscopy (XPS). Based on these data, possible reaction mechanisms of hydrogen sulfide over WO3-Cu2O (1%) surface based on dissociation of H2S molecules and spillover of hydrogen atoms onto cracked WO3 surface are discussed.