Self-assembly of copper nanoparticles (cubes, rods and spherical nanostructures): Significant role of morphology on hydrogen and oxygen evolution efficiencies

Nanocrystalline copper nanoparticles with varying morphology, nanocubes (∼50 nm), nanorods (diameter of ∼3 nm and length of ∼50 nm) and nanospheres (5 nm) have been synthesized using the microemulsion method and subsequent treatment at 400 °C in hydrogen atmosphere. The role of concentration in the self-assembly of nanoparticles in varying dimensionality has been brought out in this study. Copper nanoparticles are known to be efficient electro-catalysts for a variety of reactions. In addition, the ability of copper catalyst to generate hydrogen and oxygen in electrochemical reactions provided the impetus to understand size and shape dependence of such electro-catalytic reactions of copper in nanocrystalline form. Cube-shaped nanoparticles show significantly high hydrogen and oxygen evolution efficiencies compared to the nanorods and spherical nanoparticles. The nanospheres show higher hydrogen and oxygen evolution efficiencies than the nanorods. [Display omitted]