Potential of core-shell NiFe layered double hydroxide@Co3O4 nanostructures as cathode catalysts for oxygen reduction reaction in microbial fuel cells

To improve the activity of oxygen reduction reaction (ORR) of microbial fuel cell (MFC), the cathode was modified by using NiFe layered double hydroxide (LDH)@Co3O4 as catalyst to increase the power generation of MFC. The unique NiFe-LDH@Co3O4 core-shell structure was prepared by using NiFe-LDH as metal source, Co3O4 as support matrix and urea-doped nitrogen in LDH. XRD, FTIR, SEM and EDS showed that LDH was successfully grown on the surface of Co3O4, and had typical LDH nanostructure. The voltage output of NiFe-LDH@Co3O4 MFC was maintained at about 0.43 V, with insignificant variations over 8 d, which indicated that NiFeLDH@Co3O4 catalyst has remarkable stability and durability. Moreover, the maximum power density was 467.35 + 8.27 mW/m(2), which was produced by NiFe-LDH@Co3O4. The results implied that the improvement of ORR activity of NiFe-LDH@Co3O4 was due to its high conductivity and abundant active sites, and therefore, the power generation capacity of MFC was improved. The electrode prepared by NiFe-LDH@Co3O4 modified air cathode was a promising material for fuel cell.