Effect of Iron Oxidation on the Activity of Platinum-Decorated Iron Nanoparticles for the Hydrogen Evolution Reaction

Platinum decorated on iron nanoparticle catalysts holds significant promise for the electrochemical hydrogen evolution reaction (HER). The metal combination aims to leverage a bifunctional mechanism, where the oxophilic iron facilitates water dissociation, while hydrogen evolution occurs on the platinum sites. However, the inherent susceptibility of Fe to oxidation can undermine the catalyst stability and efficiency. To directly understand this, our study investigates the impact of Fe nanoparticle oxidation on the HER activity of deposited Pt islands, achieved through the direct growth of face-centered cubic Pt islands on Fe nanoparticles. These Pt–Fe heterostructures were evaluated for the HER, revealing a significantly detrimental impact of iron support oxidation on Pt activity. This highlights the critical challenge of substrate oxidation for the performance of Pt–M bimetallic HER catalysts. Our work underscores the necessity of mitigating support oxidation to fully realize the potential of these materials for clean energy applications.