B-doped graphene quantum dots implanted into bimetallic organic framework as a highly active and robust cathodic catalyst in the microbial fuel cell

Developing efficient and durable oxygen reduction reaction (ORR) cathodic catalysts plays an essential role in application of microbial fuel cells (MFCs). Herein, the B-doped graphene quantum dots implanted into bimetallic organic framework (BGQDs/MOF-t) are fabricated by a facile electro-deposition. Results show that, the in-situ growth of FeCoMOF on nickel foam can effectively assist construction of nanoflowers with compact connections, thus improves the conductivity. More importantly, this nano-network can serve as the template for the implantation of BGQDs through powerful interface of M-O-C bonding, avoiding π-π rearrangement and providing efficient charge transfer and abundant edge active sites. Benefitting from the enhanced electrode/electrolyte transport interface, abundant catalytic sites and low charge transfer resistance, the BGQDs/MOF-15 exhibits excellent ORR activity, superior to commercial Pt/C catalyst. In the MFC with the BGQDs/MOF-15 cathode, the maximum power density of 703.55 mW m −2 is achieved, which is 1.53 times of that of the Pt/C cathode. In addition, the BGQDs/MOF-15 cathode maintains great stability over 800 h, while that of Pt/C reduces to 61% of the initial voltage. This work opens new opportunities for developing efficient and durable MOF-derived ORR catalyst.