Bacteria-affinity aminated carbon nanotubes bridging reduced graphene oxide for highly efficient microbial electrocatalysis

Bioelectrochemical systems (BESs) exhibit great potential for simultaneous wastewater treatment and energy recovery. However, the efficiency of microbial electrocatalysis is fundamentally limited by the high resistance and poor biocompatibility of electrode materials. Herein, we construct a novel "binder-free" 3D biocompatible bioelectrode consists of 1D aminated carbon nanotubes (CNTs-NH₂) and 2D conductive reduced graphene oxide (rGO) nanosheets through one-step electrodeposition. As expected, the maximum current density reached to 3.25 ± 0.03 mA cm^-2 with the rGO@CNTs-NH₂ electrode, which is 4.33-fold higher than that of a bare rGO (0.75 ± 0.01 mA cm^-2), and is among the best performance reported for three-dimensional electrodes. The high microbial electrocatalytic activity is mainly attributed to the excellent performance of electron transfer and bacterial colonization, which originates from the 3D interconnecting scaffold, fast 1D CNTs "e-bridge" and positively charged surface.