Magnesium Cobaltite Embedded in Corncob-Derived Nitrogen-Doped Carbon as a Cathode Catalyst for Power Generation in Microbial Fuel Cells

Abstract

Microbial fuel cells (MFCs) have drawn attention among renewable energy devices. High capital cost, poor durability, and slow oxygen reduction reaction (ORR) kinetics are the major hindrances in the commercialization of the technology. In this work, an environmentally benign approach is followed to synthesize a composite of magnesium cobaltite (MgCo 2 O 4 ) embedded in nitrogen-doped carbon to optimize the performance of MFCs. Detailed characterization confirms the formation of MgCo 2 O 4 nanostructures in the catalyst treated at 700 °C. Electrochemical studies suggest the superior performance of the MgCo 2 O 4 /NC-700 catalyst with a peak reduction current of −0.068 mA and a charge transfer resistance (R ct ) of 40.5 Ω. The performance of the air cathodes is evaluated using activated sludge as inoculum in the anode chamber in single-chamber MFCs. The power output of MFC with MgCo 2 O 4 /NC-700 as an air cathode reaching 873.81 mW m −2 is 59.56 and 216.05% higher than those of MFCs with Pt/C (547.65 mW m −2 ) and Co/NC-700 (276.48 mW m −2 ) cathodes, respectively. These findings suggest that substituting magnesium in transition metal−nitrogen−carbon composites could help realize long-term application as air cathodes for power generation and wastewater treatment in MFCs.

Functionalised graphite felt anodes for enhanced power generation in membrane-less soil microbial fuel cells

“…As shown in Fig. 6a, a sharp drop in current was recorded, possibly due to the charging effect, 74 followed by a slow decrease rate. Co 3 O 4 –GF was characterized by the highest drop in the current of 5.6 mA, followed by PANI–GF (3.3 mA), PANI–Co 3 O 4 –GF (1.3 mA), and GF (0.5 mA).…”

“…The potential used in the CA tests was selected on the basis of the closed-circuit potential against the highest power output of PANI-Co 3 O 4 -GF from the polarization test conducted on day 7 of operation (measured as 246.7 mV, Table S2). As shown in Figure 6a, a sharp drop in current was recorded, possibly due to the charging effect 75 , followed by a slow decrease rate. Co 3 O 4 -GF was characterized by the highest drop in the current of 5.…”

Facility Green Electrocatalyst: Sulfur-Modified N-Doped Durian Shell Derived Graphene-like Porous Carbon for N2 Fixation

“…The excellent catalytic performance of S/N-DSPC was due to the unique cross-linked pore structure of bioderived carbon materials, which not only provides micropores for N 2 adsorption speci c surface area, but also provides channels for electron transport and electrolyte in ltration with two-dimensional graphene-like structure. [40][41] Moreover, the doping of heteroatoms promoted the exposure of more active sites in carbon materials, created abundant ENRR active sites, and enhanced the catalytic activity of materials. 42 Under the optimal potential, the experiment alternated 2 h test cycle of electrocatalytic ammonia synthesis between N 2 saturated electrolyte and Ar-saturated electrolyte.…”

Application of biowaste and nature-inspired (nano)materials in fuel cells

“…Embedding magnesium cobaltite (MgCo 2 O 4 ) in N-doped carbon (MgCo 2 O 4 /NC-700) resulted in a superior electrochemical performance in MFC compared with Pt/C. 248 To synthesize this practical electrocatalyst, hydrothermal and pyrolysis methods were employed, in which corncob and urea were used as affordable carbon and nitrogen precursors, respectively. MgCo 2 O 4 /NC-700 had higher catalytic activity toward the ORR with a more positive onset potential of 0.478 V compared with that of Co/NC-700 and Mg/NC-700.…”