The origin of enhanced electrocatalytic activity of Pt–M (M = Fe, Co, Ni, Cu, and W) alloys in PEM fuel cell cathodes: A DFT computational study

The origin of enhanced electrocatalytic activity of Pt–M (M = Fe, Co, Ni, Cu, and W) alloy catalysts in PEM fuel cell cathodes have been investigated by the periodic DFT geometry optimization and electronic structure calculations. The stability of Pt–M alloy catalysts and the electrocatalytic activity have been explained, and we confirmed that the electronic structure of surface Pt is tuned after alloying Pt with non-noble transition metals, thus leading to enhancement of the electrocatalytic activity of Pt–M alloys for the ORR. Meanwhile, a positive shift in reversible potential was predicted for OHads formation from H2O oxidation on the Pt3M alloy catalysts with Pt-skin compared to the pure Pt. Therefore, this improvement of electrocatalytic activity of the ORR can be also attributed to a positive shift of the onset potential for forming OHads on the alloys relative to the Pt catalyst; thereby the overpotential for O2 reduction is reduced. In these ways we could screen new electrocatalysts for the ORR.