Controllable synthesis of hierarchical Au/PdAg heterostructures consisting of nanosheets on nanorods with plasmon-enhanced electrocatalytic properties

Abstract

Hierarchical hybrid metal nanostructures with complex architectures are attracting considerable attention because of their tunable properties, novel functions, and promising applications. In this work, the controllable synthesis of unique hierarchical Au/PdAg heterostructures consisting of regularly aligned PdAg nanosheets epitaxially grown on Au nanorods (Au/PdAg NRNSs) was realized in the presence of a mixture of dodecyltrimethylammonium bromide (DTAB) and cetyltrimethylammonium bromide (CTAB). If DTAB was used as the single surfactant, PdAg nanodendrite-tipped Au nanorods (Au/PdAg NRNDs) were produced, whereas Pd nanoblock-tipped Au nanorods (Au/Pd NRNBs) were obtained in the absence of Ag⁺ ions. It was revealed that a desirable combination of appropriate DTAB and CTAB concentrations is crucial to the formation of the unusual Au/PdAg NRNSs. When the three nano-heterostructures were used as catalysts for the electrocatalytic hydrogen evolution reaction, the Au–PdAg NRNSs exhibited the best catalytic performance. Furthermore, all of the three heterostructures showed pronounced plasmon-enhanced electrocatalytic activity with the Au/PdAg NRNSs exhibiting the best photo-assisted electrocatalytic activity. This work may open new avenues toward rational design and controllable synthesis of well-defined heterostructured nanoparticles with novel architectures and promising applications.