Construction of Plasmonic Metal@Semiconductor Core-Shell Photocatalysts: From Epitaxial to Nonepitaxial Strategies

In recent decade, plasmonic metal@semiconductor core-shell nanostructures have sparked tremendous research interest toward development of advanced photocatalysts. This is because such materials facilitate to harness the localized surface plasmon resonant absorption of plasmonic metal nanoparticles tunable across the entire ultraviolet-visible-near infrared (UV-vis-NIR) region, for improving the photocatalytic efficiency of surrounding semiconductors via multiple energy and charge carrier flow channels. Herein, the recent synthetic progresses achieved in wet chemical preparation of plasmonic metal@semiconductor core-shell photocatalysts are outlined. Tentatively, the reported synthetic approaches are classified into three major groups including the epitaxial seeded growth, the kinetically overdriven nonepitaxial seeded growth, and the cation exchange-facilitated (CEf) nonepitaxial growth dictated by chemical thermodynamics. Special focuses are laid on elucidating the fundamental correlation of the synthetic mechanism with the crystallographic and physical properties of the resultant nanostructures that strongly dominate the synergistic coupling efficiency between plasmonic metal and semiconductor. Of these, the promise of CEf nonepitaxy in curbing the formation of interfacial defect states and promoting extraction of plasmonic hot carriers from the large lattice-mismatched hybrid photocatalysts is detailedly elaborated. A comprehensive understanding in this scope is of significance for rationally architecting the plasmonic metal@-semiconductor core-shell nanostructures toward disclosing fascinating horizons in photocatalytic solar-to-fuel conversion.

Automated summary

Plasmonic metal@semiconductor core-shell nanostructures have attracted great interest in recent years due to their ability to enhance the photocatalytic efficiency of surrounding semiconductors. This article outlines the recent progress in the wet chemical preparation of these nanostructures, with a focus on the synthetic approaches and their correlation with the physical properties of the resulting materials. The potential of cation exchange-facilitated (CEf) nonepitaxial growth in reducing interfacial defects and promoting extraction of plasmonic hot carriers is discussed in detail. Understanding these mechanisms is important for designing efficient plasmonic metal@semiconductor core-shell nanostructures for photocatalytic solar-to-fuel conversion.