Reduced graphene oxide (rGO) decorated NiO-SnO2 nanocomposite based sensor towards room temperature diabetic biomarker detection.

In the present work, reduced graphene oxide (rGO) decorated NiO-SnO 2 nanocomposites were synthesized by using a facile sol-gel process and their structural (XRD, FTIR, Raman), morphological (BET, FESEM, TEM), and optical (UV-Vis, PL) characterizations were carried out. The as-synthesized NiO-SnO 2 nanocomposite exhibited an enhancement of surface area after the incorporation of rGO and this substantial increment was expected to be beneficial for gas sensing at room temperature. Therefore, Taguchi-type sensors were fabricated and deployed for the detection of VOCs. The optimized sensor containing ∼ 3 wt% rGO in NiO-SnO 2 nanocomposite demonstrated an excellent sensing response (R g /R a ∼ 7.8) towards ∼ 10 ppm acetone at room temperature (30 ± 5 °C) with response and recovery time of ∼ 10 s and ∼ 30 s respectively. It also exhibited good reproducibility and stability over ∼ 3 months. Additionally, this sensor selectively detected trace concentration (< 1 ppm) of acetone in exhaled human breath (ethanol present in a healthy person's exhaled breath is insignificant), which is a non-invasive biomarker of diabetes. The sensing performance was analyzed from an electronic transportation point-of-view and consequent band structure modulation. The electrical property of the sensing material was illustrated using impedance spectroscopy to support the sensing mechanism. [Display omitted] • rGO decorated NiO-SnO 2 nanocomposites were prepared using sol-gel process. • Optimized Taguchi type sensor showed ∼ 7.8 response in ∼10 ppm acetone at ∼ 30 °C. • Sensor showed reproducible sensing performance and cross sensitivity was negligible. • Optimized sensor used to detect acetone (biomarker of diabetes) in exhaled breath. • The electrical properties of sensors were elucidated by impedance spectroscopy. [ABSTRACT FROM AUTHOR]