Pt1Bi1 Intermetallic Structure with Controllable C–H and C–O Bond Activation Ability for Enhanced Diethylene Glycol Oxidation

Diethylene glycol serves as a versatile building block for commercial chemicals, and development of its high-value conversion strategies with industrial prospects remains the ultimate goal. Herein, we prepare the bimetallic Pt2Bi1/TiO2 catalyst with an intermetallic structure to enable the oxidation of diethylene glycol to high-value-added diglycolic acid. Specifically, the introduction of Bi promotes the formation of hcp-type Pt1Bi1 intermetallic compounds, inducing a transition of Pt from six coordination (Pt–Pt) to three coordination (Pt–Bi). Moreover, the coordinated Bi in the elongated Pt–Bi bond weakens the bridge adsorption of O in the C–O–C bond while the electron-enriched Pt modulates the adsorption configuration of diethylene glycol into the η1-O-1 type, thereby promoting the activation of the twice C–H bond. Thanks to this synergistic effect, a record-high diglycolic acid selectivity (>75%) is obtained on the Pt1Bi1 intermetallic structure. The catalytic system was further extended to the oxidation of other polyols, including ethylene glycol, 1,3-propanediol, and glycerol, to their diacids with satisfactory catalytic performance.