Performance of Pd@FeCo Catalyst in Anion Exchange Membrane Alcohol Fuel Cells

Abstract

The performances of the core-shell nano-electrocatalysts (FeCo@Fe@Pd/CNT-OH and their monometallic Pd counterparts (Pd/CNT-OH) on carbon nanotubes in passive and active direct methanol fuel cells (DMFCs) and direct ethanol fuel cells (DEFCs) have been studied. The direct alcohol alkaline fuel cell (DAAFCs) performances of the two nanocatalysts studied revealed the outstanding performances of the core shell, FeCo@Fe@Pd catalysts over the single Pd metal on the same substrates. A fourfold increase in power density value was observed in the DEFC while a threefold increase was seen in the DMFC while operating both passive DAAFCs at moderate temperatures using the core shell nanocatalysts. The core-shell-modified electrode also gave an exceptional activity of over 50% columbic efficiency in comparison with its Pd counterpart in the passive DEFC. Density functional theory calculations carried out to further comprehend the electrocatalytic oxidation of the nanocatalysts towards both methanol and ethanol fuels corroborated the experimental findings. An increase in the readily available electrons of the partially filled d-orbitals was found to be involved in the catalytic reactions on the surface of the FeCo@Fe@Pd/CNT-OH core shell catalysts as opposed to those of the p-orbitals of Pd/CNT-OH, thus enhancing its catalytic activities in both DAAFCs.