Microwave combustion synthesis of tin oxide-decorated silica nanostructure using rice husk template for supercapacitor applications

Supercapacitors are emerged as leading energy storage device and developing new electrode materials for supercapacitors has received much scientific interest from the researchers. In this study, we have synthesized tin oxide-decorated amorphous silica (SnO₂@RH-SiO₂) nanostructures using rice husk template as a silica source via simple microwave combustion method for supercapacitor applications. XRD, FT-IR, and EDX studies obviously characterize that silica is present in amorphous form along with crystalline SnO₂ having a rutile tetragonal structure in the prepared SnO₂@RH-SiO₂ sample. Further, TEM observation indicates that prepared sample is consisting of amorphous silica nanospheres decorated with agglomerated tin oxide nanoparticles having size of 5–10 nm. Cyclic voltammetry and galvanostatic charge/discharge studies characterize the supercapacitive behavior of working electrode fabricated from prepared SnO₂@RH-SiO₂ nanostructure. The specific capacitances of SnO₂@RH-SiO₂ nanostructure are about 448, 330, 275, 240, 225, and 200 F/g with the current density value of 1, 2, 4, 6, 8, and 10 A/g, respectively. The presence SnO₂ species in SnO₂@RH-SiO₂ nanostructure can provide reactive surfaces for the adsorption/desorption charges and it facilitates the charge storage at the surface of sample. The above results suggested that the prepared SnO₂@RH-SiO₂ nanostructure has potential application for making electrochemical supercapacitors.