Novel Zn-doped SnO2 hierarchical architectures: synthesis, characterization, and gas sensing properties

Abstract

Novel Zn-doped SnO₂hierarchical architectures were synthesized by a simple hydrothermal route. The observation of field-emission electron microscopy and transmission electron microscopy showed that Zn-doped SnO₂ hierarchical architectures were composed of one-dimensional nanocones. Interestingly, these nanocones were almost parallel to each other and knitted by other parallel nanocones. The morphology of the products could be controlled by varying the concentration of Zn²⁺. A possible formation mechanism was proposed from the viewpoint of nucleation and the crystal growth habit. Evidences of dopant incorporation were demonstrated in the X-ray diffraction and X-ray photoelectron spectroscopy measurement of Zn-doped SnO₂nanocones. The UV-vis absorption spectra of samples exhibited a blue shift with a decrease of the size of nanocones. Moreover, gas sensors based on the hierarchical Zn-doped SnO₂nanocones displayed higher response to ethanol compared with the pure urchin-like SnO₂ nanostructures. Finally, based on first-principles calculations, the enhancement in sensitivity toward ethanol could be explained by the strong coulomb binding between Zn_Sn and its neighboring O vacancies.