High electricity generation achieved by depositing rGO@MnO2 composite catalysts on three-dimensional stainless steel fiber felt for preparing the energy-efficient air cathode in microbial fuel cells

Microbial fuel cells (MFCs) are a promising biotechnology that realizes the transformation of wastewater treatment from an energy consumption to an electricity generation process. However, the tedious process and the large resources consuming in preparing powder ORR catalysts are still non-negligible limiting factors for application. This study aims at proposing an energy-efficient method for preparing three-dimensional binder-free air cathode for MFCs: non-noble composite catalysts based on graphene and MnO2 are synthesized directly on stainless steel fiber felt (SSFF) by pre-fixing and electro-reducing graphene oxide on SSFF (rGO-SSFF), and then in-situ depositing MnO2 nanocatalysts on rGO-SSFF (rGO@MnO2-SSFF). The experimental results show that the ORR ability of rGO@MnO2-SSFF cathode is greater than that of Pt/C-CC cathode, even if the performance of rGO@MnO2 powder catalyst is slightly lower than that of the traditional Pt/C catalyst. The excellent performance is found to be due to the three-dimensional framework-pore structure of SSFF which helps the prepared cathode possess larger electrochemical active area (8415.18 m(2) m(-3)) than Pt/C-CC cathode (7518.13 m(2) m(-3)). The proposed method provides a new way to reduce the cost (labor, materials and energy) of air cathode while ensuring the high electricity output of MFCs. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study proposes an energy-efficient method for preparing a three-dimensional binder-free air cathode for MFCs by synthesizing non-noble composite catalysts on stainless steel fiber felt (SSFF). This method aims to reduce the cost of air cathode preparation while maintaining high electricity output of MFCs.