Fig. 3

Formation of biofilm on the Ni-F and Ni-W anode electrode. (a) and (b) The non-uniform formation of bacterial communities on the Ni-F electrode (c) and (d) Uniform colonization of bacterial communities on the nanostructure-coated nickel foam surface in the Ni-W electrode. The presence of microorganisms within the uniform bacterial matrix facilitates electron transfer. (e) and (f) The electroactive biofilm layer covering the nickel silicide nanowire structures. The formation of these matrices over the semi-metal nanostructures provides pathways from the E. coli surface to the anode electrode, enhancing the cell’s charge transfer capability.