Au/NiP core/shell nanocrystals from bimetallic heterostructures: In situ synthesis, evolution and supercapacitor properties

A synthetic route to achieve core/shell nanostructures consisting of noble metal cores and single crystal semiconductor shells with different crystal systems is proposed, which involves a simple phosphorization process from corresponding bimetallic heterostructures. The triphenylphosphine is designed to serve as both a capping agent and a phosphorous source during the formation of Au/NiP core/shell nanoparticles (NPs) from Au-Ni bimetallic heterodimers. The semiconductor shells of the obtained Au/NiP nanostructures are controlled to form single crystals with a thickness of B5 nm. The structure-dependent supercapacitor properties of Au-modified NiP nanostructures were further investigated. The synergistic effect of the metal/semiconductor nanostructure is observed to be superior to its oligomer-like counterpart when serving as a supercapacitor electrode. The specific capacitance of an electrode fabricated from core/shell NPs is 806.1 F g with a retention of 91.1% after 500 charge-discharge cycles.