Fluorane sensitive supercapacitive microcrystalline MoO3: dual application in energy storage and HF detection

Abstract

Exploring materials and device paradigms for multifunctional electrochemical applications such as supercapacitors and sensing makes materials more suitable for real-life applications. In this study, microcrystalline MoO₃ powder has been synthesized using a simple sol–gel method, and its suitability for energy storage devices and HF sensing performance has been studied. The MoO₃ microcrystallites, well-characterized using electron microscopy, X-ray diffraction, and Raman spectroscopy, have been tested for HF sensitivity on a glassy carbon electrode as well as on a carbon cloth electrode. Similarly, a solid-state prototype asymmetric supercapacitor has been demonstrated that displays its charge storage capabilities. The specific capacitance of MoO₃ increases linearly with the increase of HF concentration. Additionally, the sensing performance of MoO₃ can be seen by monitoring changes in current passing through the electrode in the presence of HF. High stability with good repeatability was displayed. In situ Raman spectroscopy, recorded during the charging and discharging process, has been used to understand the charge storage mechanism. A high sensitivity of 6656 mF mM⁻¹ g⁻¹ with a low limit of detection of 1.2 μM was observed, which makes this material suitable for sensing as well as charge storage.