Fe-N-C Composite Catalyst Derived from Solid Digestate for the Oxygen Reduction Reaction in Microbial Fuel Cells

Transforming biomass waste into cost-effective non-precious-metal catalysts for the oxygen reduction reaction (ORR) provides a great opportunity for the development of microbial fuel cells (MFCs). Herein, we report a strategy to produce Fe-N-C composites from the biomass waste and evaluate their performance as ORR electrocatalysts, involving the co-doping of Fe and N and the construction of hierarchical structure with high surface areas. The obtained catalyst, with abundant defect sites and uniform Fe and N dispersions, showed excellent activity and selectivity toward the ORR due to the synergetic effect between the doped N and Fe. In particular, with the Fe-N-C as electrocatalysts, MFCs could produce a maximum power density of up to 1308 mW m(-2), much higher than that of the N-C catalyst (638 mW m(-2)). This newly developed method, with the advantage of easily scaling up for mass production of Fe-N-C composites, not only provides an effective approach to fabricate value-added functional carbon materials but also offers an efficient way to mitigate the biomass waste-related environmental pollution