Trace N-doped manganese dioxide cooperated with Ping-pong chrysanthemum-like NiAl-layered double hydroxide on cathode for improving bioelectrochemical performance of microbial fuel cell

Abstract

Trace N-doped manganese dioxide (MnO₂) nanoparticles were attached to NiAl-layered double hydroxide (LDH) nano sheets by a simple two-step hydrothermal reaction, and N-MnO₂@NiAl-LDH was successfully prepared as cathode catalyst of microbial fuel cell (MFC). N-MnO₂@NiAl-LDH was Ping-pong chrysanthemum-like structure formed by overlapping lamellar structures, with spherical MnO₂ particles attached on. The unique Ping-pong chrysanthemum-like structure and pore size distribution provided large number of electrochemical active sites. The recombination of trace N and MnO₂ reduced the charge transfer resistance, accelerated the electron transfer rate, and N-MnO₂@NiAl-LDH showed high oxygen reduction reaction (ORR) capability. The maximum output power density of N-MnO₂@NiAl-LDH-MFC was 698 mW/m², about 4.59 times of NiAl-LDH (152.1 mW/m²). The maximum voltage was about 320 mV, and the stability was good for about 7 d. This would provide technical reference for the utilization of cathode catalyst for fuel cells.

Keywords: Layered double hydroxide (LDH); Microbial fuel cell; MnO(2); Oxygen reduction reaction.