Inverse Spinel NiCo2S4 Nanoparticles Coated on Activated Carbon As an Electrocatalyst Applied in Air Cathode Microbial Fuel Cells

Abstract

Here, the hybrid of inverse spinel NiCo2S4 nanoparticles coated on activated carbon (AC) has been first described as an effective nonprecious electrocatalyst for oxygen reduction reaction (ORR) used in air cathode microbial fuel cells (MFCs). MFC with NiCo2S4/AC air cathode obtains the maximum power density of 2000 ± 59 mW/m2, with a value of 125% higher than the control. The combination effect of mixed valence in NiCo2S4/AC composite is favorable for easier electron transfer to make O2 absorbed and reduced. The intensity ratio of Raman D to G band (ID/IG ) decreases from 0.85 (AC) to 0.78 (NiCo2S4/AC), indicating the formation of a partial graphite structure in NiCo2S4/AC.NiCo2S4/AC cathode shows better catalytic activity, lower internal resistance, higher kinetic activity and contains much octahedral catalytic active sites of Co3+, which favors a four electron ORR pathway. The finding shows NiCo2S4/AC will be a novel kind of promising nonprecious catalyst applied in MFC.