Support composition engineering of gold catalysts for efficient oxidative esterification of ethylene glycol

• Multi-component oxide supported gold catalyst for oxidative esterification of ethylene glycol to methyl glycolate. • Synergistic modulation of acid-base sites and Au electron density by multi-component support. • Activation energy reduced by ∼70 % via synthesizing the multi-component oxides supported Au. • Under the molecular oxygen mediated, realize high selective conversion of ethylene glycol to methyl glycolate. To address the overcapacity in coal-to-ethylene glycol production, developing eco-friendly process to convert ethylene glycol into high-value-added chemicals is an important topic in current industrial research. In this work, we prepared a multi-component metal oxide-supported Au catalyst through a simple physical mixing and impregnation strategy, and investigated the influence of the support composition on the catalyst activity. Among all tested catalysts, Au/NbZnAlO x exhibited the optimal catalytic performance, achieving a selectivity of 95 % for methyl glycolate, while maintaining good stability (>90 % selectivity) after five cycles. The characterization of XRD, XPS, TPD and ATR-IR indicated that the incorporation of 10 wt% ZnO and 10 wt% Al 2 O 3 into Nb 2 O 5 effectively modulates the balanced distribution of acid-base sites on the catalyst surface and the substrate adsorption capacity. Meanwhile, NbZnAlO x support endowed Au nanoparticles highest electron density, promoting the activation of O 2 , thereby enhancing the catalytic activity. Kinetic studies revealed a remarkable reduction in activation energy from 77 kJ mol -1 to 24 kJ mol -1 upon ZnO/Al 2 O 3 incorporation into Nb 2 O 5 . These findings provide insights into designing multi-component oxide-supported gold catalysts and highlight the critical importance of support composition in optimizing selective oxidation reactions. NbZnAlO x supported Au provides optimal distribution of surface acid-base site and endowed Au nanoparticles highest electron density, promoting moderate substrate adsorption strength and the activation of O 2 , thereby enhancing the catalytic activity.