Self-Assembly Intermetallic PtCu₃ Core with High-Index Faceted Pt Shell for High-Efficiency Oxygen Reduction.

Abstract

Rational design of well-defined active sites is crucial for promoting sluggish oxygen reduction reactions. Herein, leveraging the surfactant-oriented and solvent-ligand effects, we develop a facile self-assembly strategy to construct a core-shell catalyst comprising a high-index Pt shell encapsulating a PtCu₃ intermetallic core with efficient oxygen-reduction performance. Without undergoing a high-temperature route, the ordered PtCu₃ is directly fabricated through the accelerated reduction of Cu²⁺, followed by the deposition of the remaining Pt precursor onto its surface, forming high-index steps oriented by the steric hindrance of surfactant. This approach results in a high half-wave potential of 0.911 V versus reversible hydrogen electrode, with negligible deactivation even after 15000-cycle operation. <i>Operando</i> spectroscopies identify that this core-shell catalyst facilitates the conversion of oxygen-involving intermediates and ensures antidissolution ability. Theoretical investigations rationalize that this improvement is attributed to reinforced electronic interactions around high-index Pt, stabilizing the binding strength of rate-determining OH_ads species.