Iron-Nicarbazin derived platinum group metal-free electrocatalyst in scalable-size air-breathing cathodes for microbial fuel cells

Abstract

In this work, a platinum group metal-free (PGM-free) catalyst based on iron as transitional metal and Nicarbazin (NCB) as low cost organic precursor was synthesized using Sacrificial Support Method (SSM). The catalyst was then incorporated into a large area air-breathing cathode fabricated by pressing with a large diameter pellet die. The electrochemical tests in abiotic conditions revealed that after a couple of weeks of successful operation, the electrode experienced drop in performances in reason of electrolyte leakage, which was not an issue with the smaller electrodes. A decrease in the hydrophobic properties over time and a consequent cathode flooding was suspected to be the cause. On the other side, in the present work, for the first time, it was demonstrated the proof of principle and provided initial guidance for manufacturing MFC electrodes with large geometric areas. The tests in MFCs showed a maximum power density of 1.85 W m−2. The MFCs performances due to the addition of Fe-NCB were much higher compared to the iron-free material. A numerical model using Nernst-Monod and Butler-Volmer equations were used to predict the effect of electrolyte solution conductivity and distance anode-cathode on the overall MFC power output. Considering the existing conditions, the higher overall power predicted was 3.6 mW at 22.2 S m−1 and at inter-electrode distance of 1 cm.

Self-stratified and self-powered micro-supercapacitor integrated into a microbial fuel cell operating in human urine

“…Activated carbon seems to be the right choice since it is cost-effective, commercially available and durable over long terms operations [66,67]. In the past decade, PGM-free catalysts based on transition metals have also gained attention worldwide due to higher catalytic activity compared to both platinum and carbonaceous catalysts [68,69]. Large-scale production and relatively high costs still prevent its commercial implementation [54].…”

Multi‐functional microbial fuel cells for power, treatment and electro‐osmotic purification of urine

“…Highly active and durable iron–nicarbazin derived electrocatalyst (Fe‐NCB) was originally developed for future automotive applications synthesised from iron nitrate and nicarbazin (NCB) as iron salt and nitrogen rich organic precursor . Fe‐NCB was successfully used in a recent MFC study and was shown to be a promising ORR catalyst.…”

Air-breathing cathode self-powered supercapacitive microbial fuel cell with human urine as electrolyte

“…PGM-free materials are catalysts containing an earth abundant transition metal such as Fe, Co, Mn or Ni [ [45] , [46] , [47] ]. High performing PGM-free can be categorized into two main groups; the first one that use catalysts produced through pyrolysis (high temperature treatment in controlled atmosphere) of a nitrogen-rich organic precursor and a metal-containing salt [ [48] , [49] , [50] , [51] , [52] ] and the second one through deposition or impregnation of organic molecules with the metal incorporated into their structure such as porphyrins or phthalocyanines [ [53] , [54] , [55] , [56] ]. Generally, it was previously found that iron was the most active and efficient [ 57 ].…”