Hierarchical pseudo-cubic hematite nanoparticle as formaldehyde sensor

To develop a low cost and scalable gas, sensor for the detection of toxic and flammable gases with fast response and high sensitivity is extremely important for monitoring environmental pollution. This work reports a facile method for preparing pseudo-cubic hierarchical alpha-Fe2O3 nanostructured materials as well as their implementation in gas sensor application. The alpha-Fe2O3 is developed using Fe(NO3)(3) and ethylene glycol followed by a facile and one-step solvo-thermal reaction without subsequent heat treatment. The pseudo-cubic nanostructures were having an average edge length of 5-10 nm. The solvent played the role of ligand and synergistically affected olation and oxolation process along with dehydration to form final product. The sensor performance of alpha-Fe2O3 in the detection of toxic and flammable gases such as formaldehyde (HCHO), ethanol (C2H5OH), and carbon monoxide (CO) was evaluated. As-synthesized nanostructured hematite showed better sensing performance towards formaldehyde. The fabricated gas sensor showed temperature sensitivity sensing performance for the same gas. In addition, ethanol, formaldehyde vapours, and carbon monoxide gas-sensing properties were tested and the sensing performance of the synthesized material was found to be in the order of HCHO > C2H5OH > CO. This sensing performance is attributed to the large specific surface area of the pseudo-cubic nanoparticles.