Simultaneous Wastewater Treatment and Energy Generation by Polyelectrolyte-Single Wall Carbon Nanotube composite as Effective Cathode Catalyst in Air-Cathode Microbial Fuel Cells

S. Li
National University of Singapore, SG

Keywords: polyelectrolyte, cathode catalyst, microbial fuel cells, oxygen reduction reaction

Summary:

Polyelectrolyte-single wall carbon nanotube (SCNT) composites are prepared by solution-based methods and used as metal-free cathode catalysts for oxygen reduction reaction (ORR) in air-cathode microbial fuel cells (MFCs). Polydiallyldimethylammonium chloride (PDDA) and poly [bis(2-chloroethyl)ether-alt-1,3-bis[3-(dimethylamino)propyl]urea] (PEPU) polyelectrolytes with positively charged quaternary ammonium sites are used to increase oxygen affinity of SCNTs and reduce activation energy in the oxygen reduction process. The resultant composites exhibit remarkable catalytic ability towards ORR in MFC applications. It is also found that PEPU-SCNT composite based MFCs show efficient performance with maximum power density of 270.1 mW m-2, comparable to MFCs with the benchmark Pt/C catalyst (375.3 mW m-2), while PDDA-SCNT composite based MFCs produce 188.9 mW m-2. These results indicate that PEPU-SCNT and PDDA-SCNT catalysts are promising candidates of metal-free cathode catalysts for ORR in MFCs, and could facilitate MFC scaling up and commercialization.