Crystal phase-based epitaxial growth of hybrid noble metal nanostructures on 4H/fcc Au nanowires

Crystal-phase engineering offers opportunities for the rational design and synthesis of noble metal nanomaterials with unusual crystal phases that normally do not exist in bulk materials. However, it remains a challenge to use these materials as seeds to construct heterometallic nanostructures with desired crystal phases and morphologies for promising applications such as catalysis. Here, we report a strategy for the synthesis of binary and ternary hybrid noble metal nanostructures. Our synthesized crystal-phase heterostructured 4H/fcc Au nanowires enable the epitaxial growth of Ru nanorods on the 4H phase and fcc-twin boundary in Au nanowires, resulting in hybrid Au–Ru nanowires. Moreover, the method can be extended to the epitaxial growth of Rh, Ru–Rh and Ru–Pt nanorods on the 4H/fcc Au nanowires to form unique hybrid nanowires. Importantly, the Au–Ru hybrid nanowires with tunable compositions exhibit excellent electrocatalytic performance towards the hydrogen evolution reaction in alkaline media. Heterometallic nanomaterials in unusual crystal phases that are impossible to form in the bulk state can show interesting physical and chemical properties. Here, crystal-phase heterostructured 4H/fcc Au nanowires are used as seeds to epitaxially grow a variety of binary and ternary hybrid noble metal nanostructures on the phase boundary.