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[Display omitted] • Both size and support effects of Au catalysts are explored for MAL conversion. • The Au edge site is identified as the main active site for MMA generation. • A kinetics strategy for disentangling Au geometric and electronic effects is presented. The direct oxidative esterification of methacrolein (MAL) has drawn considerable attention as a promising route to produce methyl methacrylate (MMA). Here, we report a kinetics strategy to identify the active sites of Au catalyst for its disentanglement of geometric and electronic effects on this reaction. A series of Al 2 O 3 and CeO 2 supported Au catalysts are prepared by urea deposition–precipitation method, whose particle sizes are tailored by changing the vacuum-drying temperature. Their catalytic activity is correlated with Au particle size based on a crystal structure modelling, in which the Au edge site is identified as the main active site. The reduction in the valence electron population of Au 5 d states facilitates the adsorption of MAL, thus the positive core-level shift of Au 4f levels for each support gives rise to a higher production of MMA. This kinetics strategy could be extended to the design of other metal catalysts for this reaction. [ABSTRACT FROM AUTHOR]

We report the unique nanoscale alkaline earth metals doped Pt/M−MCM−41 (70) (M = Mg, Ca, Sr and Ba) catalysts for the selective oxidation of glycerol in base-free medium. Strong basic sites generated by alkaline earth metal oxides (especially MgO and CaO) could induce the strong electronic transfer ability, the modified reduction properties of Pt and abundant surface oxygen vacancies. Reaction kinetics demonstrated that the addition of alkaline earth metal oxide (e.g. CaO) could promote the activation of primary hydroxyl group and C-H bond, resulting in the excellent catalytic performance. • Basic strength-dependent catalytic performance for glycerol oxidation was investigated. • Alkaline earth metals changed the structural properties of the Pt/MCM-41 catalyst. • The promotion role of alkaline earth metal on the reaction mechanism was elucidated. • Record TOF values for the base-free oxidation of glucose and xylose were obtained. Fundamental understanding of basic site of supported metal catalysts is highly desirable for aqueous phase oxidation of alcohols without adding extra alkali. Herein, nanoscale alkaline earth metals doped Pt/M−MCM−41 catalysts (M = Mg, Ca, Sr and Ba) were prepared for the aqueous phase oxidation of glycerol to glyceric acid in base-free medium. By establishing the correlation between basic active site and catalytic performance, it is found that catalytic activity increases almost linearly with the strength of basic sites, and excessively strong basic sites are not conducive to the improvement of glyceric acid selectivity. Multi-characterizations revealed that strong basic sites generated by alkaline earth metal oxides (especially MgO and CaO) could induce the enhanced electronic transfer ability, the modified reduction properties of Pt and abundant surface oxygen vacancies in the Pt/M−MCM−41 catalysts. Moreover, reaction kinetics demonstrated that the addition of alkaline earth metal oxides (e.g. CaO) could promote the activation of primary hydroxyl group and C-H bond, resulting in the excellent catalytic performance. In addition, as the representative of the optimal solid base catalysts, the Pt/Ca-MCM-41 (70) catalyst also exhibits record high turnover frequency (TOF) values for the oxidation of glucose (9623.0 h−1) and xylose (4561.0 h−1) to corresponding carboxylic acids. [ABSTRACT FROM AUTHOR]