Enhanced activity and stability of Co3O4-decorated nitrogen-doped carbon hollow sphere catalysts for microbial fuel cells

Abstract

Microbial fuel cells (MFCs), as an ideal device, are highly attractive for renewable and sustainable energy storage. On the other hand, the development of low-cost and efficient catalysts based on earth-abundant elements for the sluggish oxygen reduction reaction (ORR) has remained elusive. Herein, a robust non-precious metal-based electrocatalyst is demonstrated, consisting of nitrogen-doped carbon hollow spheres elaborately decorated with Co₃O₄ nanoparticles (HCN-Co₃O₄). The unique structure of HCN-Co₃O₄ fully enables the utilization of synergistic effect of the high activity of Co₃O₄ and the excellent conductivity of HCN, endowing the hybrid with an excellent ORR catalytic activity in MFCs. Benefiting from intriguing structural features, HCN-Co₃O₄ exhibits a significantly enhanced electrocatalytical performance towards the ORR both in alkaline and neutral conditions, superior cycling stability, and outstanding durability compared to pure Co₃O₄ and hollow Co₃O₄ (H-Co₃O₄) spheres. Moreover, the high power density of the self-assembled MFCs equipped with the HCN-Co₃O₄ cathode also indicates the feasibility of the catalyst for practical applications.