Cation Exchange between CdSe Nanocrystals and Pd²⁺ Cations in Different Solvent Environments toward Phase-Dependent Ethanol Oxidation Electrocatalysis

The cation-exchange strategy has shown great potential to create a large variety of inorganic nanostructures. We herein report the cation-exchange reactions between CdSe nanocrystals and Pd2+ cations in different solvent environments and identify three features not sufficiently noticed before: (i) the exchange between Cd2+ and Pd2+ cations could be fully achieved in both aqueous and organic solvents and is also independent of its parent CdSe crystal structures; (ii) the exchange between Cd2+ and Pd2+ cations in aqueous solvent results in amorphous Pd-Se exchanged products, while in organic solvent, it leads to a cubic Pd17Se15 phase; and (iii) the exchanged Pd17Se15 product exhibits better electrocatalysis for ethanol oxidation reaction in an alkaline medium relative to its amorphous counterpart and the commercial Pd/C catalyst.