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 ascertaining their chemical composition, crystal phase, morphology, purity, and vibrational properties. 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 uniform diameter throughout the length of the nanowires. The average diameter of the α-MnO2 nanowires 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.
Highlights
Formaldehyde (HCHO) is classified as one of the dangerous gases and is supposed to generate indoor and outdoor pollution
It has been reported that formaldehyde can cause nasal and throat irritation in a very low concentration level of 0.08 ppm [1]
The XRD pattern of the synthesized MnO2 nanowires exhibited characteristic peaks corresponding to the α-MnO2 crystal phase
Summary
Formaldehyde (HCHO) is classified as one of the dangerous gases and is supposed to generate indoor and outdoor pollution. Formaldehyde is widely used in the chemical and textile industries, including the manufacturing of adhesives and the processing of wood products, paper, synthetic polymers, and more. It is used as a preservative in the form of formalin for the storage of biological specimens. Even though it is used in various biological and industrial applications, long-term exposure to formaldehyde can cause cancer, asthma, leukemia, and other diseases. It has been reported that formaldehyde can cause nasal and throat irritation in a very low concentration level of 0.08 ppm [1]. The International Agency for Research on Cancer (IARC) has identified it as a first class carcinogenic substance [2,3]
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