Room-Temperature Synthesis of Intermetallic Cu–Zn by an Electrochemically Induced Phase Transformation

Ordered intermetallic compounds (OICs) are useful materials for applications ranging from catalysis to optoelectronics. However, generalizable synthetic methods for preparing OIC nanomaterials composed of an electropositive metal and late transition metal has remained a substantial challenge. Herein, we report a process for synthesizing ordered intermetallic γ-Cu5Zn8 or intermetallic β-CuZn (high-temperature phase) from Zn-rich Cu alloys at room temperature and atmospheric pressure by an electrochemically induced phase transformation (EIPT). In the EIPT process, Zn is dissolved from the lattice by electrochemical corrosion, initiating the reorganization of the crystal to an intermetallic phase. The transformation of ϵ-CuZn4 (space group: P63/mmc) to ordered intermetallic γ-Cu5Zn8 (space group: I4̅3m) or intermetallic β-CuZn (space group: I4̅3m) is controlled by the potential and electrolyte used during dealloying. The phases that were accessed was gated by the thermodynamic stability of Zn-rich Cu alloys in aqueous electrolytes. These results have established a key development in the synthesis of intermetallic nanomaterials at room temperature and atmospheric pressure.