One pot synthesis of octahedral {111} CuIr gradient alloy nanocrystals with a Cu-rich core and an Ir-rich surface and their usage as efficient water splitting catalyst

A facile one pot synthetic route has been developed to obtain octahedral CuIr nanocrystals with Ir-rich {111} facets. Co-decomposition of Cu and Ir precursors in the presence of CTAC (cetyltrimethylammonium chloride) forms CuIr nanocrystals with an Ir-rich {111} facet. A mechanistic study reveals that the surface Cu atoms of the initially formed octahedral-shaped Cu-rich Cu-Ir alloy nanoparticles are replaced by Ir atoms via a galvanic replacement reaction. The formation of the Ir phase is rather slow, leading to the impermeable nature of the Ir shell, which does not allow the dissolution of the Cu phase. The CuIr nanocrystals with an Ir-rich shell show high catalytic activity toward oxygen evolution reaction.