Enhanced acetone sensor based on Au functionalized In-doped ZnSnO₃ nanofibers synthesized by electrospinning method

Nobel metal modification could be a valuable method for the fabrication of advanced chemiresistive gas sensor. Herein, a series of Au loaded In-doped ZnSnO₃ nanofibers were prepared via electrospinning technique. The crystal structure, morphology and chemical composition of the synthesized materials were characterized by field-emission X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), elemental mapping, X-ray photoelectron spectroscopy (XPS) and Brunauere-Emmette-Teller (BET) analyses. The optimal sensor, which was based on 0.25 mol% Au loaded In-doped ZnSnO₃ nanofibers, could detect 50 ppm acetone effectively, it possessed a high response (19.3) and fast response/recovery time (10/13 s) at low operating temperature (200 °C). The enhanced gas sensing performance was mainly derived from proper introduction of Au. Since the electronic catalysis of Au nanoparticles created Schottky barrier-type junctions at Au and ZnSnO₃ interfaces which could cause tremendous change of resistance and induce to high sensitivity, meanwhile the chemical catalysis of Au nanoparticles promoted the chemisorption and dissociation of gas molecules which could accelerate the reaction with gas sensing material. Moreover, the Au loaded In-doped ZnSnO₃ sensors displayed certain stability under different humidity condition, it meant that the negative influence of water vapor on gas sensing performance could be inhibited by loading Au nanoparticles.