Gas selectivity of nanostructured ZnSb2O6 synthesized by a colloidal method

ZnSb2O6 with trirutile-type structure was prepared by a microwave-assisted colloidal method. Stoichiometric amounts of zinc nitrate, antimony trichloride and n-dodecylamine, dissolved in ethyl alcohol, were used in the synthesis. The thermal decomposition of the precursor produced single-phase ZnSb2O6 at 500 °C. The formation of a large number of micro and nanowires, with particles attached to their surface, was observed by SEM and TEM. The size of the attached particles was in the range 50 nm to 1.2 μm; whereas the length of the wires was between 80 μm and 120 μm. The nanostructures of ZnSb2O6 obtained in this work were not previously reported. The use of other surfactants may provide simple ways to obtain different micro and nanostructures of this oxide. The CO, O2 and CO2 gas sensing properties of ZnSb2O6 thick films were evaluated in alternate current, measuring the magnitude of the impedance (|Z|). Different operating temperatures and applied frequencies were tested, however, a reproducible detection of the gases was registered at 400 °C and 100 kHz. Gas selectivity was also a relevant characteristic of this material. Besides, the response to these gases confirmed that ZnSb2O6 is an n-type semiconductor. The films detected variations in the concentration of the gases. In excess O2 and CO, a non-linear behavior was registered; whereas in CO2, a quasi-linear trend was observed.