Au doped ZnO/SnO2 composite nanofibers for enhanced H2S gas sensing performance

Abstract

Nanofibers of ZnO-SnO2 nanocomposites doped with Au crystals were synthesized by an electrospinning method for enhancement of H2S gas sensing performance. The mixed solution of zinc acetate dihydrate and tin(II) chloride dihydrate, dissolved in ethanol/DMF solvent, was spun directly on the interdigital Pt electrodes for sensor fabrication. Thermal treatment was carried out to convert the spun nanofibers into ZnO-SnO2 nanocomposites doped with Au crystals. SEM and TEM observation confirmed the formation of porous nanofibers with an average diameter of about 120 nm. X-ray diffraction studies revealed that the nanocomposites of ZnO and SnO2 phases were formed, but not ZnSnO3, despite the precursor solution being mixed on the atomic scale from the starting solution. Doping with 0.001, 0.005 and 0.01 wt.% of Au slightly changed the morphology of the nanofibers because the Au was not doped into the crystals of ZnO or SnO2, but mostly existed as the surface decoration. This ensured that the effective surface catalyzed the gas reaction, thus enhance the sensing performance. Gas sensitivity to H2S gas was improved by approximately 700% with the optimal doping concentration of Au.