Enhanced cathode performance of a rGO–V2O5 nanocomposite catalyst for microbial fuel cell applications

Abstract

A reduced graphene oxide–V₂O₅ nanocomposite was synthesized by a low temperature surfactant free hydrothermal method and its MFC performance was assessed. The structural properties of the synthesized nanocomposite were studied by X-ray diffraction. Field emission scanning electron microscopy of the nanocomposite revealed a wrinkled paper-like structure of rGO and a nanobelt-like structure of V₂O₅. This study estimated the viability of the graphene-based nanocomposite rGO–V₂O₅ as a novel cathode catalyst in single chamber air-cathode MFCs. A series of MFCs with different catalyst loadings were produced. The electrochemical behavior of the MFCs was calculated by cyclic voltammetry. The MFCs with the rGO–V₂O₅ nanocomposite cathode exhibited superior maximum power densities (83%) to those with the pure V₂O₅ cathodes. The rGO–V₂O₅ with a double-loaded nanocomposite catalyst achieved an enhanced power density of 1668 ± 11 mW m⁻² and an OCP of 698 ± 4 mV, which was 83% of that estimated for the Pt/C 2004 ± 15 mW m⁻² nanocomposite cathode. The significant increase in power density suggests that the reduced graphene oxide–V₂O₅ nanocomposite is a promising material for MFC applications. The CV result showed good agreement with the MFC result. The prepared rGO–V₂O₅ nanocomposite cathode, particularly with a double loading catalyst, is promising as a sustainable low-cost green material for stable power generation and long-term operation of MFCs.