Within a flask containing Milli-Q water, with the approximate volume added to result in 50 mL, 200 µL of 1 M HCl was added. Subsequently, 125 µL of seeds were added, followed by the addition of HAuCl4, AgNO3, and ascorbic acid. HAuCl4, AgNO3, and ascorbic acid were added in a 2:2:1 ratio. The volumes of HAuCl4 used in this experiment include 250 μL, 500 μL, and 2 mL.