Preparation of CuO/CNF composite and its performance as anode in a microbial fuel cell with Shewanella oneidensis in a half cell configuration

Abstract

The route to produce a composite material comprised of carbon nanofibers (CNFs) decorated with CuO nanoleaves. This material exhibits a significant potential as an anode in microbial fuel cells (MFCs). The CNFs were obtained through a combined process of electrospinning and subsequent heat treatment; while CuO nanostructures were synthesized via oil-in-water microemulsion. The modified CNF were prepared by hydrothermal treatment at different conditions and the best result was obtained when a CuO paste (recovered from 100 g of a microemulsion) was used. The composite was characterized by transmission and scanning electron microscopy coupled with energy dispersive X-ray detector, X-ray diffraction, selected area electron diffraction, Raman, and X-ray photoelectron spectroscopy. The material presented a 23.2 m2/g surface area and a pore diameter of about 7.3 nm, which is higher than the materials that are commonly used as anodes. The electric resistance of the material was 11.0 Ω, which is 50% lower than the pristine CNF resistance value. In addition, the biocompatibility of CNF/CuO was studied with a pure Shewanella oneidensis MR-1 BAA-1096TM culture through optical density and colony forming units. In this study, the voltage obtained with CNF decorated with CuO nanoleaves in a half MFC was of 0.337 V vs. NHE and this value remained constant for 44 h. The high stability of the voltage over an extended period can be considered as a promising result that will have a positive effect on the efficiency and performance of a MFC using CNFs decorated with CuO nanoleaves as an anode.