Fabrication of hollow In2O3–ZnO microtubules by a simple biotemplate method and their gas-sensing properties

Biomorphic In 2 O 3 –ZnO hollow microtubules were synthesized by using cotton as template and followed by calcination. This environmental-friendly method using biomaterials as templates can be used to synthesize metal oxide semiconductor materials with specific morphologies. The structural and microscopy characterization were carried out with X-ray diffraction, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy. The SEM images display the porous structure of the as-obtained hollow microtubules, which is beneficial to increase gas sensing properties of materials. Gas sensors based on In 2 O 3 -doped ZnO hollow microtubules were investigated and the test results demonstrate the excellent acetone sensing properties of such porous materials. The response of In 2 O 3 –ZnO hollow microtubule sensors to 100 ppm acetone at the optimum temperature of 300 °C is 62.5, meanwhile the response and recovery times are 3 and 7 s, respectively. Moreover, even at 0.1 ppm of acetone detectable response can be observed, and the value is 2.82. At the same time the sensors have selectivity to acetone.