Anion-induced oxygen vacancies regulate Zn/CeMO catalyst active domain to efficiently catalyze acetylene hydration

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To enhance the catalytic performance of Zn-based catalysts for the coal-based acetylene process synthetic acetaldehyde, increased density of active species, accelerated water dissociation kinetics, and improved dispersion of Zn components are the main methods. In this study, the high-temperature calcination of Ce-LDH precursors effectively removes interlayer anions, yielding CeMO supports with abundant and homogeneously distributed oxygen vacancies. The superior Zn/CeMO-850 catalyst displayed the better catalytic performance and stability with 80 ​% acetylene conversion and 82 ​% acetaldehyde selectivity for the acetylene hydration under the reaction conditions (T ​= ​260 ​°C, GHSV (C2H2) ​= ​90 h −1 and V H2O /V C2H2 ​= ​4). High-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) showed that the oxygen-vacancy-enriched CeMO carriers could produce more hydroxyl zinc reactive species for the Zn/CeMO catalysts. The energy spectroscopy analysis (EDS) and X-ray diffraction analysis (XRD) results demonstrated that the oxygen-vacancy-enriched CeMO carriers were able to effectively improve the dispersion of the reactive metal component and inhibit the metal agglomeration for the Zn/CeMO catalysts. Density-functional theory (DFT) calculations showed that the presence of oxygen vacancies could improve the increase of reactants and reduce the reaction energy barrier resulting in the improvement of reaction rate and catalytic performance. This work provides fundamental insights for designing oxygen-enriched supports to optimize Zn-based catalysts. High-temperature calcination of Ce-LDH precursors effectively removes interlayer anions, yielding CeMO supports with abundant and homogeneously distributed oxygen vacancies. These structural features could promote the formation of reactive zinc-hydroxyl species, enhance active component dispersion while suppressing metal sintering, and facilitate reactant adsorption/activation resulting to the lower reaction energy barriers. Collectively, these effects significantly accelerate reaction kinetics and enhance catalytic performance in the reaction. • Oxygen vacancies significantly enhanced Zn-catalyst activity in acetylene hydration. • Oxygen vacancies promoted uniform dispersion of Zn species and increase active site density. • DFT calculations confirmed oxygen vacancies strengthen adsorption, lower energy barriers, and accelerate kinetics.