Overcoming the Oxygen Activation Barrier: Dual-Functional Ce-OH Sites for Methanol Adsorption and Oxidation

Engineering dual-functional sites that couple reactant adsorption with oxygen activation is a crucial strategy for enhancing catalytic oxidation. Despite the known adsorption function of metal hydroxyl groups, their role in activating molecular oxygen and driving subsequent oxidation reactions remains poorly understood. Herein, Ce-OH sites were rationally constructed within Ce-ZSM-5 channels via ion exchange into Brønsted acid sites (BAS), forming Z[Ce4+(OH)3]+ sites that integrate methanol adsorption with the more critical function of O2 activation. These sites reduce the O2 activation barrier to 1.12 eV, compared with BAS in H-ZSM-5 (3.35 eV) and CeO2 (1.39 eV). DFT calculations further reveal that, over Z[Ce4+(OH)3]+ sites, methanol oxidation proceeds via a pathway in which O2 adsorption and activation are concerted with *HCHO formation, with the decomposition of *HCHO identified as the rate-determining step (with a barrier of 1.55 eV). This cooperative mechanism, engaging both the Ce center and adjacent hydroxyl groups, promotes methanol deprotonation and C-H bond cleavage while simultaneously activating O2, thereby enabling efficient oxidation─a function inaccessible to BAS. These findings provide fundamental insights into oxygen activation over Ce-OH sites and offer a rational strategy for designing zeolite-based catalysts with tailored dual-functional sites for catalytic oxidation.