Mechanism for toluene detection of flower-like ZnO sensors prepared by hydrothermal approach: Charge transfer

A facile and efficient hydrothermal route was used to synthesize flower-like ZnO. The morphology and composition of ZnO were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The XRD results that pure ZnO were formed without any other impurity peaks. Uniformly distributed flower-like ZnO were clearly observed from the SEM images. A possible growth model was proposed to simulate the formation of flower-like ZnO. The fabricated ZnO sensors exhibited good response to toluene than to other interfering gases such as acetone, ammonia and benzene. On the perspective of bond dissociation energy discrepancy, the good selectivity of the ZnO sensor to toluene was explained in detail. A reasonable sensing mechanism of ZnO sensor to toluene was proposed in the aspect of charge transfer.