Interfacial Auδ--OV-Zr3+ structure promoted C H bond activation for oxidative esterification of methacrolein to Methyl methacrylate

Constructing abundant metal-support interfacial active sites is an effective strategy to boost catalytic performance toward interfacial electronic structure-sensitive reactions, such as oxidative esterification of oxygenates. Herein, we successfully promote the generation of the interfacial active sites via tuning the crystal phases of Au/ZrO2 catalysts. Multi-characterizations (such as in-situ FT-IR spectra and reaction kinetics) and density functional theory (DFT) calculations demonstrated that the interfacial Auδ--OV-Zr3+ structure with the synergistic effect exhibits strong electrons transfer from tetragonal-ZrO2 to Au atom. Specifically, the OV-Zr3+ could facilitate the adsorption of methacrolein substrate, and the electron-rich Auδ- species could promote the CH bond activation of the CH2C(CH3)CHOOCH3 intermediate. Therefore, the interface-rich Au/t-ZrO2 catalyst achieved nearly 90 % yield of MMA and excellent catalyst stability without the incorporation of second promoter. The outcome of this work could provide some insights into developing an efficient Au-based catalyst in the oxidative esterification system.