Usage of gold nanoparticles/multi-walled carbon nanotubes-modified CPE as a nano-bioanode for enhanced power and current generation in microbial fuel cell

Anode electrode is an important component and a main factor limiting the performance of microbial fuel cells (MFCs). Among various anode materials which have been used so far to improve the performance of MFCs are carbon nanotubes (CNTs) whose usage are limited due mainly to their cellular toxicity features. In this work, a practical solution to this problem was introduced through coupling CNTs with the synthesized gold nanoparticles (GNPs). Four different anodes such as: bare carbon paste electrode (CPE), CNT-modified carbon paste electrode (CNT/CPE), GNP-modified CPE (GNP/CPE), and GNP-modified CNT/CPE (GNP/CNT/CPE) were fabricated and then their electrochemical behaviors were investigated by electrochemical techniques. Also, the electrocatalytic behavior of these electrodes was studied in the anodic chamber of a two-chambered MFC system. By applying the GNP/CNT/CPE, the MFC system produced a maximum power density of 80 mW/m2 and a maximum current density of 460 mA/m2, which was, respectively, about 30- and 15-fold higher than that of the unmodified CPE. Therefore, the GNP/CNT/CPE seemed to have a great potential as a biocompatible nano-bioanode to be used in MFCs for further electricity generation improvement. Finally, the electron transfer rate constants of both bare CPE and GNP/CNT/CPE were calculated.