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.

The 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.211