Synergistic interfacial engineering and orbital hybridization in a polyoxometalates@porous aromatic framework catalyst for efficient ethanol oxidative esterification

Abstract

The efficient oxidation esterification of bioethanol in the liquid phase remains challenging. Herein, polyoxometalates supported on a porous aromatic framework catalyst (PW₁₁Co@iPAF-2) are synthesized for the one-pot production of ethyl acetate (EA) from ethanol, yielding 89.6% EA. The interaction between PW₁₁Co and iPAF-2 effectively regulates the orbital electron distribution of Co²⁺, promoting the activation of ethanol by PW₁₁Co. Furthermore, the pore structure of iPAF-2 excludes water molecules, thereby reducing the local water concentration around the PW₁₁Co active site. This localized anhydrous microenvironment is conducive to the reversible reaction proceeding in the forward direction, leading to high selectivity for EA. This research offers a new perspective on designing more efficient esterification catalysts.