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

摘要

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 nonprecious metal-based electrocatalyst is demonstrated, consisting of nitrogen-doped carbon hollow spheres elaborately decorated with Co3O4 nanoparticles (HCN-Co3O4). The unique structure of HCNCo3O4 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.