Phase-transfer interface promoted corrosion from PtNi10 nanoctahedra to Pt4Ni nanoframes

A novel two-phase approach towards the corrosion of PtNi10 nanoctahedra has been developed. In this strategy, the active component of Ni in oil-soluble PtNi10 nanoctahedra which resided in the upper toluene phase, suffered from etching and was then transferred into a lower aqueous phase with coordination by ethylenediaminetetraacetate (EDTA). Due to the existence of the phase-transfer interface promoted by EDTA, the corrosion reaction proceeded at an accelerated rate under the mild conditions. Specifically, the resultant products of octahedral Pt4Ni nanoframes were successfully fabricated for the first time, and PtNi4 porous octahedra could be obtained when the dosage of EDTA-2Na was reduced. After a systematic study of this two-phase system, a synergetic corrosion mechanism is proposed to account for the formation of octahedral Pt4Ni nanoframes, involving contributions from many species (i.e., O-2, H2O, H+, OAm, and EDTA(4-)). As a result of the fascinating three-dimensional geometry of Pt4Ni nanoframes and PtNi4 porous octahedra, both of the corroded nanocrystals showed superior activity over the pristine PtNi10 nanoctahedra for ethanol electrooxidation in alkaline media and hydrogenation of nitrobenzene.