Green reduction of graphene oxide as a substitute of acidic reducing agents for supercapacitor applications

Abstract

Graphene has emerged as one of the most fascinating materials for the scientific community. The exceptional properties of graphene make it a better candidate than the existing materials. So far, the reduced form of graphene oxide (GO) is the best substitute for large quantity graphene. There are numerous ways of reducing GO via synthetic reducing agents that are not eco-friendly and cost-effective. This investigation aims to expand the scope for the reduction of GO using naturally existing reducing agents. In the present work, a comparative study of the extent of reduction using metal/acids and vitamin C containing green reductants is done. The X-ray diffraction peak for GO was detected at 2θ = 10.8° which gradually shifted to higher 2θ values (24-26°) after reduction, indicating that GO was reduced well using all the reductants. The C/O ratio of GO (calculated by XPS), gradually increased from 2.5 to 4–5 for all the reducing agents. Inspired by the better reduction in lemon reduced GO (LrGO), its electrochemical characterization was performed using cyclic voltammetry (CV). The increased supercapacitive value validates the improved electrochemical behavior of LrGO over GO. Finally, our findings conclude that green reductant (lemon juice) serves as a good, eco-friendly, and economic reducing agent for the synthesis of reduced graphene oxide with improved electrochemical properties.