Precise control over the topology of plasmonic metal-semiconductor heteronanostructures is essential for fully harnessing their plasmonic function and hence for designing innovative solar energy conversion platforms. Here, we present a rational synthesis strategy for the realization of plasmonic metal-semiconductor heteronanocrystals with intended configurations through the site-selective overgrowth of semiconductor CuO on desired sites of anisotropic Au nanocrystals. Both the exploitation of structural characteristics of Au nanocrystals and the selective stabilization of their surfaces are keys to the construction of heteronanocrystals with a specific configuration. Our approach can provide an opportunity to precisely explore the link between the solar energy conversion efficiency and the structure of heteronanocrystals as well as to obtain important insights into the underpinning mechanism. Heteronanocrystals produced by CuO overgrowth preferentially on the multiple high-curvature sites of Au nanocrystals exhibited prominent photocatalytic hydrogen production activity due to efficient charge separation by strong plasmon excitation at the Au-CuO interface and subsequent sustainable hot electron transfer from Au to CuO.

A synthesis strategy for the preparation of ultrathin free-standing ternary-alloy nanosheets is reported. Ultrathin Pd-Pt-Ag nanosheets with a thickness of approximately 3 nm were successfully prepared by co-reduction of the metal precursors in an appropriate molar ratio in the presence of CO. Both the presence of CO and the interplay between the constituent metals provide fine control over the anisotropic two-dimensional growth of the ternary-alloy nanostructure. The prepared Pd-Pt-Ag nanosheets were superior catalysts of ethanol electrooxidation owing to their specific structural and compositional characteristics. This approach will pave the way for the design of multicomponent 2D nanomaterials with unprecedented functions.

Incorporation of catalytically active materials into plasmonic metal nanostructures can efficiently merge the reactivity and energy-harvesting abilities of both types of materials for visible light photocatalysis. Herein, we explore the influence of electromagnetic hotspots in the ability of plasmonic core–shell colloidal structures to induce chemical transformations. For this study, we developed a synthetic strategy for the fabrication of Au nanoparticle (NP) trimers in aqueous solution through fine controlled galvanic replacement between Ag nanoprisms and Au precursors. Core–shell Au@M NP trimers with catalytically active metals (M = Pd, Pt) were subsequently synthesized using Au NP trimers as templates. Our experimental and computational results highlight the synergy of geometry and composition in plasmonic catalysts for plasmon-driven chemical reactions.

The controlled synthesis of metal–semiconductor yolk–shell heteronanostructures with high photocatalytic performance was achieved through a facile aqueous method.