In-situ synthesis of SnO2/SBA-15 hybrid nanocomposite as highly efficient humidity sensor

We report a hydrothermally derived novel scheme to synthesize SnO2 supported mesoporous SBA-15 nanocomposite for relative humidity (RH) sensing at room temperature. Two loading procedures of SnO2 nanoparticles in SBA-15 were followed: in-situ and wet impregnation, in order to reveal information regarding the effect of synthesis strategies on the RH sensing response of the nanocomposite. The obtained nanocomposites were characterized using a combination of X-ray diffraction (XRD), N-2 adsorption-desorption isotherms, high resolution transmission electron microscope (HRTEM), field emission scanning electron microscope (FESEM) and energy dispersive X-ray (EDX) spectroscopy. The humidity sensing properties of the presented nanocomposite sensor, such as linearity, response-recovery characteristics, hysteresis and stability, were investigated by exposing sensors to wide range of 11-98%RH at room temperature. Due to uniform and homogeneous dispersion of SnO2 nanoparticles in the pore channels of SBA-15, the nanocomposite sensor synthesized using in-situ process not only exhibit superior sensing response towards change in %RH but also posses swift response-recovery time, good repeatability, negligible hysteresis and stability, highlighting the unique advantages of the synthesis procedures for fabrication of sensor materials. The complex impedance spectra of the sensor at different RHs were analyzed to explore the humidity-sensing mechanism. This study demonstrates that the SnO2/SBA-15 nanocomposite prepared by in-situ method can be used as the humidity-sensing material for the fabrication of humidity sensors. 2015 Elsevier B.V. All rights reserved.