Hierarchical Chitosan/Carbon Composites for Enhancing Electricity Generation Performance of Geobacter sulfurreducens

Two types of chitosan/carbon composites including chitosan/carbon nanotubes (CS/CNTs) and chitosan/carbon black (CS/CB) were utilized to modify graphite electrode for the electrochemically active biofilm (EAB) growth of Geobacter sulfurreducens. The hierarchically novel carbon composites modified electrodes have been obtained via facile vacuum freeze-drying. CS/CNTs (5 h) showed porous structure and CS/CB (5 h) exhibited the lamellar structure. Compared with the control, the maximum current densities of EAB growth on the CS/CNTs (5 h) increased by 135%, CS/CNTs (10 h) with longer time only increased by 56%. Unexpectedly, the EAB growth on CS/CB (5 h) modified electrode showed relatively better performance than that of CS/CNTs (5 h) increasing by 16.7%. In addition, CS/CB (10 h) modified electrode increased by 48.9% comparing with CS/CNTs (10 h). It can be seen that the CS/CB with 5 h freeze-drying possessed a better characteristic structure for promoting EAB growth and enhancing performance.