Co-impregnated aquatic biomass-based biochar as an oxygen reduction reaction catalyst for bioelectricity generation from membrane-less single-chambered microbial fuel cells

Abstract

The excellent electrocatalyst of cobalt nanoparticles supported on water hyacinth is prepared through pyrolysis at various temperatures, such as 400, 500, 600, and 700 °C. It observed that WH500 (cobalt nanomaterial supported on water hyacinth) obtained by pyrolysis at 500 °C, and on using as a cathode electrocatalyst in a membrane-less single-chambered microbial fuel cell (SC-MFC), it shows higher conductivity and excellent oxygen reduction reaction (ORR) performance. Physicochemical characterizations are performed to indicate the structural and functional groups of the synthesized biochar. Morphological studies show that cobalt nanoparticles are consistently distributed in catalyst WH500. Cyclic voltammetry (CV) results show that the catalyst WH500 at a potential of −0.058 mV with a −0.238 mA reduction current demonstrates a higher electrocatalytic activity toward ORR than other prepared electrocatalysts. Moreover, in chronoamperometric studies, catalyst WH500 demonstrates excellent stability with higher initial current (0.111 mA) and limiting current (0.007 mA) values. Furthermore, microbial fuel cell (MFC) coated with catalyst WH500 at the air cathode side produces a maximum power density of 435.97 mW /m², higher than that of other MFCs. The nanocomposites showed excellent ORR behavior due to longer stability and electronic conductivity. Briefly, WH500 catalyst is a favorable ORR catalyst in the real-world application of MFCs.

Graphical Abstract