Activated Porous Highly Enriched Platinum and Palladium Electrocatalysts from Dealloyed Noncrystalline Alloys for Enhanced Hydrogen Evolution

Abstract Modulation of activity of a quasicrystalline or amorphous matrix by selective dealloying of a less reactive metal is a trade‐off between an activity increment due to enhanced electronic structure/surface area and an activity decrement due to an increase in crystallinity. We evaluate this trade‐off in melt‐spun ribbons of amorphous PtZr 4 and quasicrystalline PdZr 3 metallic glasses for the hydrogen evolution reaction (HER). Selective electrochemical dissolution of Zr generates highly porous, stable, predominantly Pt and Pd electrocatalysts and having three and eight times higher HER specific activity. Dealloyed Pt has two times higher specific HER activity than dealloyed Pd. The heat of mixing between Pt (Pd) and Zr is correlated to the extent of dealloying from PtZr 4 (PdZr 3 ) alloys. Dealloying glass‐forming element Zr enhances the activity of the resultant porous material due to the reduction in oxide layer formation and better optimized M−H bond strength. X‐ray photoelectron spectroscopy analysis suggests that activity enhancement is due to Pt/Pd atoms gaining a partial negative charge leading to the promotion of H + absorption and an increase of HER activity upon dealloying. The present work also provides insight into the challenging search for a glass‐former that does not have a debilitating effect on the electronic structure of the noble metals.