Hydrothermally synthesised n-n heterostructured ZnO-SnO 2 composites: A novel solution for formaldehyde detection

This work presents the hydrothermally synthesised and detailed investigation on pure ZnO, SnO 2 and n-n heterostructured ZnO-SnO 2 composite materials for the detection of formaldehyde under ambient conditions. The sensor material was structurally and morphologically characterized by X-ray diffraction technique, Raman spectroscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Chemical properties of the prepared materials were studied using energy-dispersive X-ray spectroscopy and X-ray photo electron spectroscopy. Gas sensing studies were performed with liquid distribution technique towards various volatile organic compounds such as acetone, benzene, ethanol, methanol and formaldehyde under ambient conditions. Among these gases formaldehyde has shown good response towards n-n heterostructured ZnO-SnO 2 composite material with a response and recovery times of 36s and 24 s under ambient conditions.