Vertically Oriented Metallic Heterodimer Array Semiembedded in Flat Conductive Carbon Film for Electrochemical Application

General synthesis of a highly oriented metallic heterodimer array based on a selective electrodeposition technique onto a metal nanoparticle-embedded carbon film is proposed, which enables the preparation of heterodimers with a wide variety of metal combinations. This method requires no surfactant, capping agent, organic solvent, or heat treatment. As a representative metal combination, a nickel (Ni)/palladium (Pd) heterodimer array was prepared by selective electrodeposition of Ni nanoparticles (Ni NPs) on top of partially exposed Pd NPs embedded in carbon film electrodes fabricated by a cosputtering technique. Such a selective electrodeposition becomes possible by utilizing the difference in electrodeposition overpotentials between carbon and Pd NP surfaces. X-ray photoelectron spectroscopy revealed a charge transfer from Ni NPs to Pd NPs, implying that the catalytic and optical properties can be expected to be controllable. The formed heterodimer array structure was mechanically stable against ultrasonication in ethanol for over 1 h because most parts of the Pd NPs were tightly embedded in the carbon film. After conversion from Ni to nickel hydroxide (Ni(OH)(2)), the electrode showed high electrocatalytic activity toward glucose oxidation, with a higher turnover rate and lower overpotential to Ni(OH)(2) on carbon film electrodes.

Automated summary

A method for the synthesis of highly oriented metallic heterodimer arrays on a metal nanoparticle-embedded carbon film using a selective electrodeposition technique is proposed. This method does not require the use of surfactants, capping agents, organic solvents, or heat treatment. Selective electrodeposition is achieved by utilizing the difference in electrodeposition overpotentials between carbon and Pd nanoparticle surfaces.