High power density output and durability of microbial fuel cells enabled by dispersed cobalt nanoparticles on nitrogen-doped carbon as the cathode electrocatalyst.

To endow microbial fuel cells (MFCs) with low cost, long-term stability and high-power output, a novel cobalt-based cathode electrocatalyst (Nano-Co@NC) is synthesized from a polygonal metal-organic framework ZIF-67. After calcining the resultant ZIF-67, the as-synthesized Nano-Co@NC is characteristic of cobalt nanoparticles (Nano-Co) embedded in nitrogen-doped carbon (NC) that inherits the morphology of ZIF-67 with a large surface area. The Nano-Co particles that are highly dispersed and firmly fixed on NC not only ensure electrocatalytic activity of Nano-Co@NC toward the oxygen reduction reaction on the cathode, but also inhibit the growth of non-electrogenic bacteria on the anode. Consequently, the MFC using Nano-Co@NC as the cathode electrocatalyst demonstrates excellent performance, delivering a comparable initial power density and exhibiting far better durability than that using Pt/C (20 wt%) as the cathode electrocatalyst. The low cost and the excellent performance of Nano-Co@NC make it promising for MFCs to be used in practice.