Abstract Deuterium(D)‐labeled aromatics play an essential part in the Yield of fine chemicals. However, deuteration reactions are particularly dependent on the specific chemical environment of the metal to finish the oxidative addition and reductive elimination. Herein, a complex valence Pt/Ca 12 Al 14 O x catalyst was successfully synthesized for the deuteration of toluene using inexpensive D 2 O. It exhibited high deuteration efficiency, achieving 96% deuteration in just 4 hours, 14% higher than the most commonly Pt/C catalyst. The catalyst can also be reactivated and recycled up to 16 times. Multiple characterization techniques were used to demonstrate the interaction between Pt and Ca 12 Al 14 O x generates the co‐existence of Pt(δ+) and Pt(0). The synergy between Pt(δ+) and Pt(0) can promote the completion of oxidation and elimination reactions. Thus, the complex valence of Pt improves the processes required for H−D exchange and boosts the reaction rate and stability of the hydrogen isotope exchange system.