The In Situ Electrochemical-Chemical Cascade Strategy for Pyruvic Acid Synthesis

Hydrogen peroxide (H₂O₂), as a green oxidizing medium, can be generated and utilized in situ via an electrochemical-chemical cascade, enabling organic transformations while enhancing efficiency and selectivity. However, balancing high H₂O₂ production, efficient activation, and selective substrate conversion remains challenging. Herein, a series of transition metal-doped CeO₂ catalysts were developed for electrocatalytic H₂O₂ generation and its subsequent use in converting α-hydroxy acids to pyruvate. Among them, Ni-CeO₂ exhibited the best performance, achieving a pyruvate production rate of 19.9 mmol g^-1 h^-1 and a Faradaic efficiency of 55.3%. Mechanistic studies revealed that transition metal doping regulates the local coordination environment and oxygen vacancy concentration, thereby optimizing the adsorption strength of the *OOH intermediate, which governs the two-electron oxygen reduction reaction pathway and H₂O₂ generation and release. Furthermore, in situ generated H₂O₂ was selectively activated on the catalyst surface to form a reactive oxygen species network dominated by hydroxyl radicals (·OH) and assisted by singlet oxygen (¹O₂). Among these, ·OH showed the lowest energy barrier for α-C─H bond activation and subsequent electron rearrangement, making it the key species for pyruvate formation. This work provides a new strategy for the preparation of value-added chemicals.