Atomic-scale engineering of Pt shells on chiral Au nanoparticles for enhanced oxygen reduction.

Spin selection in chiral nanocatalysts enabled by the chiral-induced spin polarization (CISS) effect has emerged as a promising strategy for boosting the performance of the oxygen reduction reaction (ORR). However, achieving atomic-scale control of catalytically active surfaces on chiral nanostructures remains challenging. Herein, we demonstrate an approach for the atomic-level engineering of Pt shells on chiral substrates to enhance ORR performance. Pt shells with controlled thicknesses are deposited on chiral Au nanoparticles through a combined protocol of cyclic underpotential deposition and galvanic replacement reaction. This strategy not only maximizes the atomic utilization efficiency of Pt but also preserves the chiral geometry of the substrate and its chiroptical activity. For the chiral Au@Pt nanocatalysts, a volcano-type relationship is observed between the Pt shell thickness and ORR performance. The chiral Au@Pt nanoparticles exhibit a capability of spin polarization due to the CISS-like effect and competitive ORR activities. This work establishes a route for fabricating catalytically active chiral nanocatalysts with CISS-like effects, thereby laying a foundation for the development of advanced spin-selective electrocatalysts.