Soybean powder enables the synthesis of Fe-N-C catalysts with high ORR activities in microbial fuel cell applications

摘要

The development of microbial fuel cells (MFCs) into a new type of carbon-neutral wastewater treatment technology requires efficient and low-cost oxygen reduction reaction catalysts in air cathodes. The use of raw soybean powder was investigated for synthesizing Fe-N-C ORR catalysts in a sacrificial SiO2 support method. ZnCl2 etching in the synthesis was found to facilitate the formation of hierarchical porous structures of Fe-N-C catalysts. Fe-N-C(1-1) catalyst synthesized with an optimal soybean/ZnCl2 mass ratio of 1:1 exhibited the highest ORR activity in air cathodes. The use of the obtained Fe-N-C(1-1) catalyst enables a maximum power production of similar to 0.480 mW cm(-2) in MFCs, higher than commercial Pt/C (0.438 mW cm(-2)) with the same catalyst loading of 2 mg cm(-2). Long-term MFC operations demonstrated that the Fe-N-C synthesized from raw soybean have high stability and toxic tolerance, indicating that abundant low cost soybean biomass is a potential material for ORR catalyst development in MFC applications. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.