Three-dimensional electrode interface assembled from rGO nanosheets and carbon nanotubes for highly electrocatalytic oxygen reduction

Abstract Microbial fuel cells (MFCs) exhibit great potential for simultaneous wastewater treatment and energy recovery. However, sluggish cathodic oxygen reduction reaction (ORR) and expensive catalyst cost greatly retard further developments of MFCs. Herein, three-dimensional electrode interface was assembled from reduced graphene oxide nanosheets and carbon nanotubes (rGO@CNTs) through one-step electrodeposition method, and high electricity output performance of MFCs was obtained. To be noted, one-dimensional pristine CNTs could restrain the rGO stacking and enhance the electrode conductivity, and two-dimensional rGO sheets can prevent the bundling of CNTs. Furthermore, a certain amount of oxygen containing functional groups on rGO surface guarantees sufficient active sites and adequate conductivity. Compared with pure rGO and commercial Pt/C catalyst, the as-prepared rGO@CNTs electrode exhibits a superior ORR electrocatalytic performance (high catalytic activity and superior durability). In addition, being applied as sensitive films on MFC cathode, a high power density of 378.3 mW m−2 was achieved, which far prevails over commercial Pt/C catalyst (240.1 mW m−2) and pure rGO (84.6 mW m−2). This work develops a simple and low-cost modification method to construct high-performance catalytic electrode in bioelectrochemical systems.