In-situ hydrothermally derived highly responsive MgO doped mesoporous KIT-6 based novel humidity sensor

Abstract

ABSTRACT Herein in this work, the synthesis as well as study of Magnesium-oxide loaded mesoporous silica KIT-6 (a 3D material, first synthesised by Ryoo’s research group in 2003 material, in Korean Institute of Technology) for sensing at room temperature was done by employing KIT-6 as a hard template. The unique arrangement mesoporous KIT-6 having Ia3d symmetry along with a three-dimensional cubic arrangement of pore provides more tunnels for transportation of charge carriers. Water molecules are more effectively adsorbable due to KIT-6’s extremely porous structure, and the mesoporous framework’s broad, uniform pore channels make it simple for charged ions to flow freely. Despite these qualities, undoped KIT-6 does not exhibit a superior relative humidity (RH) sensitivity in humid environments hence metallic nanoparticles (MgO/KIT-6) have been used to improve the sensing capabilities of RH sensors. In the current work, we offer a straightforward, easy-to-follow hydrothermal synthesis method for producing effective humidity sensing materials made of MgO-loaded KIT-6. Different MgO concentrations (1, 5 and 10 wt%) were added to KIT-6 in order to employ it as a humidity sensor material to effectively monitor and regulate humidity levels. Here at MgO/KIT-6 presents swift humidity response and recovery time along with it change in ≥3 orders of magnitude in resistance were observed over as compared to pure KIT-6 in the 11%–98% RH range at room temperature. The structural insights were examined using X-ray diffraction (XRD), Fourier transform infrared, High-resolution transmission electron microscopy , Field emission scanning electron microscopy with energy dispersive x-ray (EDX) microanalysis and textural properties of the synthesised mesoporous KIT-6 silica and MgO/KIT-6 (X) nanocomposites were examined in depth with the N2 adsorption-desorption isotherm from which it was analysed that as the amount of MgO is incremented, the surface area gets decreased. Among all the tested samples of different weight%, optimal results obtained for 5 weight% MgO-loaded KIT-6 [abbreviated as MgO/KIT-6(5)] exhibits impressive humidity sensing responsiveness, little hysteresis, short response as well as recovery time (31 s/35 s), consistent linearity, extremely high accuracy over a varied working temperature range, repeatability and great stability in the 11–98% RH range. The investigation of humidity sensing properties of MgO/KIT-6 hybrid nanocomposite justifies that this material is good candidates to be used as a innovative high performance humidity sensor.