Silver grass-derived activated carbon with coexisting micro-, meso- and macropores as excellent bioanodes for microbial colonization and power generation in sustainable microbial fuel cells.

Schematic illustration of working mechanism of SGAC-based MFCs. • Highly porous activated carbon bioanode derived from low-cost silver-grass biomass. • Hierarchically porous architecture with co-existence of micro-, meso- and macropores. • Unprecedented surface area of 3027 m2 g−1 and pore volume of 1.3186 cm3 g−1. • Delivered maximum power of 963 mW cm−2 in MFC using E. coli as biocatalyst. • Superior biocompatibility and excellent extracellular electron transfer. In this study, highly biocompatible three-dimensional hierarchically porous activated carbon from the low-cost silver grass (Miscanthus sacchariflorus) has been fabricated through a facile carbonization approach and tested it as bioanode in microbial fuel cell (MFC) using Escherichia coli as biocatalyst. This silver grass-derived activated carbon (SGAC) exhibited an unprecedented specific surface area of 3027 m2 g−1 with the coexistence of several micro-, meso-, and macropores. The synergistic effect from pore structure (macropores — hosting E. coli to form biofilm and facilitates internal mass transfer; mesopores — favors fast electron transfer; and micropores — promotes nutrient transport to the biofilm) with very high surface area facilitates excellent extracellular electron transfer (EET) between the anode and biofilm which resulted in higher power output of 963 mW cm−2. Based on superior biocompatibility, low cost, environment-friendliness, and facile fabrication, the proposed SGAC bioanode could have a great potential for high-performance and cost-effective sustainable MFCs. [ABSTRACT FROM AUTHOR]