Cubic shaped hematite (α-Fe2O3) micro-structures composed of stacked nanosheets for rapid ethanol sensor application

Abstract

Herein, the synthesis, characterization, and ethanol gas sensing properties of hematite iron oxide(α-Fe2O3) microstructures were investigated. Detailed examinations using different techniques confirmed the high-density growth and rhombohedral crystal structure of the synthesized Fe2O3 micro-structures with an average crystal size of 38.29 nm. The appearance of several Raman-active A1g(1), A1g(2), and Eg modes in Raman-scattering spectrum further revealed the formation of the hematite phase. The sensor device was fabricated using Fe2O3 micro-structures and tested for various gases such as ethanol, carbon monoxide (CO), and hydrogen (H2). It was observed that the fabricated sensor demonstrated a high response of 13.1for 100 ppm ethanol gas concentration at a temperature of 400 °C. Including the response and recovery times for the fabricated sensors, the transient response for various gases was also recorded and analyzed. The fabricated sensor exhibited a rapid gas response at 400 °C for ethanol gas (13.1) compared to CO (1.95) and H2 (1.71) gases for 100 ppm gas concentrations. A plausible ethanol sensing mechanism was also proposed and presented.