Atomic Au₃Cu Palisade Interlayer in Core@Shell Nanostructures for Efficient Kirkendall Effect Mediation

Abstract

Plasmonic Cu@semiconductor heteronanocrystals (HNCs) have many favorable properties, but the synthesis of solid structures is often hindered by the nanoscale Kirkendall effect. Herein, we present the use of an atomically thin Au 3 Cu palisade interlayer to reduce lattice mismatch and mediate the Kirkendall effect, enabling the successive topological synthesis of Cu@Au 3 Cu@Ag, Cu@Au 3 Cu@Ag 2 S, and further transformed solid Cu@ Au 3 Cu@CdS core−shell HNCs via cation exchange. The atomically thin and intact Au 3 Cu palisade interlayer effectively modulates the diffusion kinetics of Cu atoms as demonstrated by experimental and theoretical investigations and simultaneously alleviates the lattice mismatch between Cu and Ag as well as Cu and CdS. The Cu@Au 3 Cu@CdS HNCs feature exceptional crystallinity and atomically organized heterointerfaces between the plasmonic metal and the semiconductor. This results in the efficient plasmon-induced injection of hot electrons from Cu@Au 3 Cu into the CdS shell, enabling the Cu@Au 3 Cu@CdS HNCs to achieve high activity and selectivity for the photocatalytic reduction of CO 2 to CO.

Aqueous Topological Synthesis of Au@semiconductor Core–Shell Nanocrystals with Morphology and Composition Engineering

“…Colloidal core–shell nanocrystals (C–S NCs), especially the noble metal@semiconductor (NMS) C–S NCs with plasmon-exciton coupling effect, are an essential class of materials due to their tunable optical and electrical properties. − NMS C–S NCs have kept the controllable localized surface plasmon resonance (LSPR) effect from the noble metal, the widely tunable absorption benefiting from various compositions, and the maximum degree of functional coupling corresponding to the most extensive contact areas. − In the past decades, many strategies have been utilized to synthesize NMS C–S NCs, such as vapor deposition, molecular beam epitaxy, and colloidal epitaxial growth. − Beyond this, it is desirable to assume a general strategy with not only flexible morphology and composition engineering but also hydrophilic surface chemistry.…”