Computational studies of iron carbide (Fe₃C) and Pt(111) as materials for electrocatalysis for hydrazine fuel cell

Fuel cells have become a promising source of energy for vehicular power but the most common fuel (hydrogen) poses storage and

transportation problems. Nitrogen-based fuels, such as hydrazine (N₂H₄), present an alternative as a solution to this problem due to their

high energy density and easy transportation. Because of these properties, hydrazine have been a subject of recent investigations. Hydrazine

oxidation is a thermodynamically favourable reaction but slow, desiring a need for an efficient electrocatalyst.

N₂H₄ + O₂ ---> N₂ + 2H₂O E₀= 1.56V vs. NHE

We use density functional theory calculations to study carbide materials (Fe₃C and others) as catalysts for hydrazine oxidation reaction

(HzOR) in hydrazine fuel cells and as support materials in traditional hydrogen-based PEMFCs. We calculate the free energies of the

adsorbed intermediates in the HzOR pathway and compare the results for Pt(111) and Fe₃C. We find that the the adsorption free energies of

the intermediates are consistently lower on Fe₃C than on Pt(111), indicating the stronger bonding between the molecular adsorbate

intermediate and the carbide surface compared to the Pt(111) metal.