α-MnO2 Nanowires as Potential Scaffolds for a High-Performance Formaldehyde Gas Sensor Device

Abstract

Herein, we report a chemi-resistive sensing method for the detection of formaldehyde (HCHO) gas. For this, α-MnO2 nanowires were synthesized hydrothermally and examined for as-certaining their chemical composition, crystal phase, morphology, purity, and vibrational proper-ties. The XRD pattern confirmed the high crystallinity and purity of the α-MnO2 nanowires. FESEM images confirmed a random orientation and smooth-surfaced wire-shaped morphologies for as-synthesized α-MnO2 nanowires. Further, the synthesized nanowires with rounded tips had a uni-form diameter throughout the length of the nanowires. The average diameter of the α-MnO2 nan-owires was found to be 62.18 nm and the average length was ~2.0 μm. Further, at an optimized temperature of 300 °C, the fabricated HCHO sensor based on α-MnO2 nanowires demonstrated gas response, response, and recovery times of 19.37, 18, and 30 s, respectively.