Hydrothermal synthesis of an SnO2–rGO nanocomposite using tea extract as a reducing agent for daylight-driven photocatalyst and supercapacitors

Abstract

In this study, SnO₂–reduced graphene oxide (rGO) nanocomposites (NCs) were synthesized via a hydrothermal method using tea extract as a reducing agent. The composition and structural properties of the NC were analysed using different techniques such as X-ray diffractometry, field-emission scanning electron microscopy, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy techniques. The prepared NCs show good photocatalytic activity of 98% within 60 min towards methylene blue dye. Moreover, the prepared NCs exhibit good structural stability after being used in catalysis. Furthermore, cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy studies were used to examine the supercapacitor behaviour of the synthesized SnO₂–rGO NCs. Due to the conducting nature of rGO, excellent electrochemical performance of the SnO₂–rGO composite was observed. The combined effect of SnO₂ and rGO in a binary composite leads to an enhanced specific capacitance of 296 F g⁻¹ at a current density of 1 A g⁻¹. The SnO₂–rGO NCs show advantages in terms of both catalytic and energy storage applications compared with their bare counterparts (SnO₂ and rGO). Therefore, SnO₂–rGO NCs may be a suitable material for use in environmental water cleaning purposes and energy storage devices due to their high efficiency and stability.