Silver nanoparticles decorated on the surface of reduced graphene oxide coated titanium oxide nanocomposite for enhanced electrochemical supercapacitance performance

In this study, Ag-rGO@TiO2 nanocomposite was prepared as an active electrode material for efficient supercapacitor applications. For this, TiO(2 )nanostructures synthesized by the hydrolysis of titanium isopropoxide were coated with GO followed by high-temperature heating to get rGO@TiO2. Thus prepared rGO@TiO2 was anchored with Ag by chemical route to get Ag-rGO@TiO2. The morphological analysis of Ag-rGO@TiO2 by scanning electron microscopy and transmission electron microscopy showed clusters of TiO2 coated as well as embedded in rGO sheets with well-dispersed Ag nanoparticles. The structural analysis by X-ray diffraction showed peaks of TiO2 and Ag, also indicated few layered rGO with an absence of graphitic impurities and this was also confirmed by the Raman analysis. Furthermore, cyclic voltammetry and galvanic charge-discharge were done in 2 M KOH using a three-electrode cell system. From electrochemical results, Ag-rGO@TiO2 delivered the highest specific capacitance of 345 Fg(-1) in contrast to 145 Fg(-1) and 105 Fg(-1) calculated for rGO@TiO2 and TiO2 nanostructures, respectively. The high specific capacitance of Ag-rGO@TiO2 is due to the presence of rGO and Ag nanoparticles which increases the electrical conductivity of nanocomposite and provides extra channels for electron transfer. Also, Ag-rGO@TiO2 showed 80% specific capacitance retention after 3000 charge-discharge cycles.