Roa, V., Cea, S., Pazo-Carballo, C., Llanos, J., Olivares, D., Escalona, N., Leiva, A., Hidalgo-Rosa, Y., Zarate, X., Dongil, A. B. & Schott, E. (2025). Sulfate-Modified MOF-808 as Superacid Catalysts: A Performance Evaluation of Zr (IV) and Hf (IV) Analogues in Acetalization Reactions. Dalton Transactions. https://doi.org/10.1039/D5DT00608B

Abstract: In this study, we report the synthesis and characterization of MOF-808-SO₄-M (M = Zr(IV), Hf(IV)), derived from MOF-808-M precursors. The introduction of sulfate groups enhances the Brønsted acidity of these materials, significantly improving their catalytic performance in the benzaldehyde acetalization reaction. The materials were characterized using powder X-ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FT-IR), nitrogen adsorption–desorption analysis, thermogravimetric analysis (TGA), energy-dispersive spectroscopy (EDS), and Hammett indicator tests. Catalytic evaluation revealed that MOF-808-SO₄-Zr exhibited significantly higher conversion compared to its Hf-based analogue, a difference attributed to its greater density of acid sites, as confirmed by temperature-programmed surface reaction (TPSR) analysis. These experimental results were further supported by density functional theory (DFT) calculations, which provided insights into the acidic properties and catalytic behavior of the materials.