The cell surface c-type cytochromes (c-Cyts) of Shewanella oneidensis demonstrated irreversible electrochemistry and sluggish electron transfer (ET) rate. c-Cyts could accumulate at the Shewanella-electrode interface when a more positive potential was applied to the electrode. Such accumulation may insulate the electrode from flavins, a more effective ET pathway utilized by Shewanella. This potential-dependent physiology had been observed with Ferrimonas balearica as well, which is genetically distant from S. oneidensis. This supported the representiveness of the model exoelectrogen. To promote the heterogeneous ET through S. oneidensis outer membrane c-Cyts, the electrode was modified with carbon nanotubes (CNTs). This modification transformed the rectification behavior of the OM c-Cyts and enhanced their heterogeneous rate constant. The bioelectrocatalytic current generation recorded by chronoamperometry was increased for over 80 times. Furthermore, in a fuel cell catalyzed by mixed microbial consortium, the CNT modified anode was shown to enhance power generation with promoted ET kinetics.