Bifunctional investigation of ultra-small SnO 2 nanoparticle decorated rGO for ozone sensing and supercapacitor applications.

Ultrasmall SnO 2 nanoparticles with an average size of 7 nm were synthesized by a hydrothermal method and composited with reduced graphene oxide (rGO) through an ultrasonic assisted solution process. The structural, functional, morphological and compositional properties of synthesised SnO 2 and rGO/SnO 2 were studied by XRD, FTIR, HRSEM, HRTEM, XPS and Raman analyses. The prepared materials were developed as a film over a PVA/KOH conductive layer coated substrate with varying thickness of 3, 5 and 7 μm to study their ozone sensing characteristics at room temperature. The physico-chemical properties reveal that the fabricated SnO 2 and rGO/SnO 2 nanocomposite films have a strong interaction with the ozone gas. Among the fabricated composite films rGO/SnO 2 -S1 film exhibits high ozone sensing response (38%) at room temperature. Additionally, the electrochemical performance of SnO 2 and rGO/SnO 2 nanocomposites was analysed and the rGO/SnO 2 nanocomposite exhibited higher specific capacitance (545 F g -1 ) than that of pure SnO 2 (236 F g -1 ) at a current density of 1 A g -1 with higher cyclic stability (96%) than that of pure SnO 2 (86%) at the current density of 20 A g -1 for a continuous 5000 charge-discharge cycles. Thus, the rGO/SnO 2 nanocomposite showed an excellent ozone sensing and energy storage performance.