Symmetry‐Induced Regulation of Pt Strain Derived from Pt₃Ga Intermetallic for Boosting Oxygen Reduction Reaction

Abstract

Pt‐based fuel cell catalysts with excellent activity and stability for proton‐exchange membrane fuel cells (PEMFCs) have been developed through strain regulation in recent years. Herein, this work demonstrates that symmetry‐induced strain regulation of Pt surface of PtGa intermetallic compounds can greatly enhance the catalytic performance of the oxygen reduction reaction (ORR). With the strain environment varies derived from the lattice mismatch of analogous PtGa core but different symmetry, the Pt surface of the PtGa alloy and the Pt3Ga (Pmm) precisely realize 0.58% and 2.7% compressive strain compared to the Pt3Ga (P4/mmm). Experimental and theoretical results reveal that when the compressive stress of the Pt lattice increases, the desorption process of O* intermediates becomes accelerated, which is conducive to oxygen reduction. The Pt3Ga (Pmm) with high symmetry and compressive Pt surface exhibit the highest mass and specific activities of 2.18 A mgPt−1 and 5.36 mA cm−2, respectively, which are more than one order of magnitude higher than those of commercial Pt/C catalysts. This work demonstrates that material symmetry can be used to precisely modulate Pt surface stress to enhance the ORR, as well as provide a distinct platform to investigate the relationship between Pt compressibility and catalytic activity.

New perspective crosslinking electrochemistry and other research fields: beyond electrochemical reactors

“…The above-discussed PEM–CCM technology has been extensively utilized in the fields of water electrolysis and fuel cells. 47–56 In particular, such water electrolysis technology has been deeply developed for O 2 generation on space stations. Although traditional water electrolysis technology has been challenging for home O 2 generators due to the production of large amounts of explosive hydrogen at the cathode, adopting the ORR–OER coupled electrocatalytic system may effectively circumvents this issue.…”

Surface Strain Effect on Electrocatalytic Hydrogen Evolution Reaction of Pt-Based Intermetallics

“…Therefore, the rational design of the surface strain is pivotal to the development of highly effective HER catalysts, which implies the importance of understanding the correlation between the HER activity and the surface strain. Previous studies have showed that the core in core–shell catalysts plays a crucial role in determining the level of surface strain and the electronic structure of the surface Pt. − Currently, there are two classes of widely used core materials: one is disordered alloys (solid solutions), which can induce favorable surface strain; however, the induced surface strains are uneven due to the random and nonuniform elemental distribution of the alloy cores. The other is monometallic cores (e.g., Pd@Pt and Ru@Pt), which can reduce the usage of precious Pt; but these suffer from the limited availability of monometallic materials for Pt skin construction, thereby restricting the range of induced strain.…”