Hollow structures have attracted ever-growing interest owing to their various excellent properties. However, a facile strategy for their fabrication is still desired. Herein, PdPt alloy with three different morphologies, that is, cubes, hollow cubes, and truncated octahedrons, is synthesized by using a one-pot, template-free method. The mechanism and dynamics of this system is also studied in detail. In particular, the hollow cubic structure represents enhanced catalytic activity in both coupling reactions and in the electrochemical oxidation of formic acid.