Dr A Muthukrishnan
Assistant Professor Grade I (Chemistry)
  +91 (0)471 - 2778104
  muthukrishnan@iisertvm.ac.in

Resent days, non-precious metal catalysts are considered as the potential replacements in the place of conventional platinum-based electro-catalysts in low-temperature fuel cells. Especially, Fe-containing nitrogen-doped carbon catalysts (Fe-C/N) are widely studied for the fuel cell applications. Though the activity of the Fe-C/N catalysts are comparable with the platinum-based catalysts, suffers due to its poor stability. Understanding the active site information and the mechanism of the oxygen reduction reaction (ORR) on Fe-N/C catalysts helps to design the active and durable catalysts for the ORR.

Our recent research involved in studying the kinetics and mechanism of the ORR on the Fe-N/C catalysts, synthesised from the polyimide and Fe salt. The individual rate constants for the ORR is studied using the Damjanovic model as shown below

stimated rate constants support the direct 4-electron reduction of oxygen and its comparably stable studied from the stability experiments. The factors affecting the stability of the electrocatalysts can be analysed using chemical state of nitrogen and Fe. The chemically stable nitrogen species is also tested for the further support to the above predictions.

Our recent results of the ORR on Fe-N/C catalysts synthesized from the polyamides gives a general view of the ORR on non-precious metal-carbon based catalysts. The peroxide pathway is predominantly followed in this case, studied from the loading density-dependent rate constants estimation.

The results demonstrate the Damjanovic model is overestimating the rate constants for the direct 4-electron reduction of ORR.

(ACS Catal. 2015, 5, 5194-5202)
(J. Phys. Chem. C 2016, 120 (39), 22515-22525)