Formation of Porous Gold Electrodeposits by Pulse Technique in AlCl3–NaCl–KCl Molten Salt Containing AuCl

Abstract

This study investigated the electrodeposition behavior of Al–Au alloys in AlCl3–NaCl–KCl molten salt containing AuCl at 443 K, and porous gold was formed by potential pulse electrolysis in the molten salt. The deposition/dissolution potential of Au in the molten salt was approximately 2.0 V vs. Al/Al(III). For the Al–Au alloy electrodeposits obtained by constant potential electrolysis, the Au concentration was less than 1 at% at potentials lower than 0.0 V. Then the Au concentration increased sharply to 84 at% at 0.0 V and increased gradually to 92 at% at 0.3 V and 98 at% at 0.9 V. Porous gold was formed by potential pulse electrolysis with repeated Al–Au alloys electrodeposition and Al dissolution. The specific surface area of the electrodeposits obtained by potential pulse electrolysis increased with decreasing frequency. The specific surface area of porous gold obtained in this experiment was up to 9.2 m2 g−1.

Keywords

• molten salt
• al–au alloy
• pulse deposition
• porous gold