Au/Ni12P5 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/Ni12P5 core/shell nanoparticles (NPs) from Au-Ni bimetallic heterodimers. The semiconductor shells of the obtained Au/Ni12P5 nanostructures are controlled to form single crystals with a thickness of ∼5 nm. The structure-dependent supercapacitor properties of Au-modified Ni12P5 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−1 with a retention of 91.1% after 500 charge–discharge cycles. Chinese researchers have designed a simple and efficient route to fabricating nanoparticles comprised of a gold core coated with a single-crystal-thick layer of a nickel phosphide semiconductor. Synthesis of this type of core-shell nanoparticle was previously problematic. Sibin Duan and Rongming Wang from Beihang University and University of Science and Technology Beijing in China examined the nanoparticles created using their new scheme under the microscope and by X-ray and found they contained few defects. They then assessed the electrochemical properties of the particles and showed that they have better supercapacitor properties than both nickel phosphide alone and gold-nickel phosphide nanoparticles without the core-shell design. The researchers' new synthesis could be used to make core-shell nanoparticles for a wide range of applications including energy storage materials, such as lithium-ion batteries, and electrochemical sensors. Au/Ni12P5 core/shell nanocrystals with single crystalline shells are synthesized via an in situ phosphorization of dumbbell-like Au–Ni nanoparticles (NPs) as precursors. The obtained core/shell Au/Ni12P5 NPs are served as supercapacitor electrode materials with distinct enhanced super-capacitance characteristics compared with pure Ni12P5 and oligomer-like Au–Ni12P5 NPs. This synthesis method provides a new strategy to fabricate metal–semiconductor nanomaterials for enhanced properties.