Ethanol gas sensing properties of hydrothermally grown α-MnO₂ nanorods

In the present work, nanorods of alpha-manganese dioxide (α-MnO₂ NRs) have been successfully synthesized using simple and cost-effective hydrothermal method, which further are utilized as a potential ethanol gas sensing material. As-synthesized α-MnO₂ NRs are characterized for their structure and morphology by means of X-ray diffraction, Raman spectroscopy, energy dispersive X-ray spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, and atomic force microscopy measurement techniques, respectively. Structural elucidation confirms the formation of phase-pure tetragonal α-MnO₂. Randomly distributed α-MnO₂ NRs demonstrate average diameter of ∼50–60 nm and length ∼1–1.5 μm. Gas sensing properties of α-MnO₂ NRs carried out systematically, as a function of time, towards various target gases and operating temperatures, corroborate excellent selectivity towards ethanol at 180 °C as an optimum operating temperature in addition to detect as little as 10 ppm ethanol gas. Furthermore, α-MnO₂ NRs sensor shows the superior reproducibility and stability in response upon consecutive exposure of ethanol at 180 °C. Gas sensing study reveals the applicability of α-MnO₂ NRs as a promising sensing material in the developing ethanol-based gas sensors.