Graphene oxide supported magnesium oxide as an efficient cathode catalyst for power generation and wastewater treatment in single chamber microbial fuel cells

•A facile and effective method to synthesize graphene oxide/magnesium oxide nanocomposite.•Magnesium oxide catalyst is successfully attached with surface of graphene oxide.•Microbial fuel cells with GO/MgO generate a high power density of 755.63 mW m−2.•This composite electrode exhibits excellent electrocatalytic activity.

Microbial fuel cell (MFC) is a promising device which can simultaneously deal with pollutions and generate renewable electricity power. In a single-chamber MFC, the performance of cathode catalyst is one of the key factors that determine power generation. In this study, we applied the nanoflower-shaped graphene oxide hybridized MgO (GO/MgO) nanocomposite to the cathode carbon cloth, which could significantly optimize the reactors' performance at a low price. A series of characterizations on GO/MgO confirmed that the magnesium oxide was successfully decorated on the surface of graphene oxide. The oxygen reduction reaction (ORR) test of cathode indicated that the electrochemical activity of GO/MgO cathode was higher than a bare MgO cathode or pure GO cathode. Consequently, the power density of MFC catalyzed by GO/MgO was enhanced to 755.63 mW m−2, which was equivalent to 86.78% of MFCs catalyzed by Pt/C (870.75 mW m−2). In addition, it obtained a chemical oxygen demand removal efficiency of 79.5%, and a coulombic efficiency of 31.6%, which also saw the best result among the three cathodes. After approximately 20 cycles running, the power density of the MFC used GO/MgO cathode kept still a stable level. Especially, it saved 93.3% cost while comparing to Pt/C catalyst, but achieved a similar electrochemical result, which helps to realize a scale-up design.

Graphical abstractThe synthesized GO/MgO nanoflower with high electrocatalytic performance can be used as cathode catalyst in single chamber microbial fuel cell to generate bioelectricity and degrade organic matters.Download high-res image (211KB)Download full-size image