Modulation of Highly Ordered Au–Cu₂O Core–Satellite Nanostructures for Enhanced Photocatalytic Performance

Janus nanostructures, distinguished by their inherent asymmetry, have attracted considerable attention due to their potential in diverse applications, particularly in photocatalysis. However, conventional single-island Janus structures are limited by their simplified surface architecture, which lead to fewer active sites and restricted electron/photon interaction pathways. Herein, we propose a strategy based on interfacial control to fabricate core–satellite (CSt) nanostructures, wherein polycrystalline Au nanoparticles (pc-Au NPs) serve as seeds for the controlled growth of copper(I) oxide (Cu₂O) islands. Strong ligand-mediated interfacial interactions enable precise regulation of Cu₂O growth on polycrystalline Au seeds, leading to well-defined core–satellite configurations. This architecture enhances interfacial area and creates multiple Au–Cu₂O interfaces that facilitate synergistic charge separation and directional transport. As a result, the core–satellite structures exhibit markedly improved photocatalytic performance compared with their single-island and core–shell counterparts. This work underscores the structural advantages of core–satellite nanostructures and provides a tunable platform for designing high-efficiency photocatalysts in energy conversion and related applications.