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

• Constructing more interfacial Auδ--O V -Zr3+ active sites by tuning the crystal structure of ZrO 2 supports. • Interfacial Auδ--O V -Zr3+ structure exhibits strong electrons transfer from tetragonal-ZrO 2 to Au atom. • The O V -Zr3+ could facilitate the adsorption of methacrolein substrate. • The electron-rich Auδ- species could promote the C H bond activation of the negatively charged intermediate. 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/ZrO 2 catalysts. Multi-characterizations (such as in-situ FT-IR spectra and reaction kinetics) and density functional theory (DFT) calculations demonstrated that the interfacial Auδ--O V -Zr3+ structure with the synergistic effect exhibits strong electrons transfer from tetragonal-ZrO 2 to Au atom. Specifically, the O V -Zr3+ could facilitate the adsorption of methacrolein substrate, and the electron-rich Auδ- species could promote the C H bond activation of the CH 2 C(CH 3)CHOOCH 3 intermediate. Therefore, the interface-rich Au/t-ZrO 2 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. [ABSTRACT FROM AUTHOR]