Stabilizing copper particles by silanol nests on modified silicalite-1 for ethanol dehydrogenation

Abstract

Copper(Cu)-based catalysts are highly promising candidates for ethanol dehydrogenation owing to their exceptional activity in cleaving O-H and C-H bonds. Nevertheless, their widespread application is hindered by challenges such as rapid deactivation and complex preparation procedures. Herein, inspired by the deactivation mechanism of Cu/MFI (silicalite-1) catalysts, two strategies, i.e., using mixed solvents for impregnation and enriching silanol nests of MFI to anchor Cu particles, were used to synthesize Cu/MFI-R catalysts with high stability and activity. The mixed solvent approach reduces the surface tension of solvents, enhancing the uniform dispersion of Cu over the hydrophobic surface of MFI. Subsequently, a MFI-R support with abundant silanol nests was synthesized via optimizing hydrothermal conditions, as confirmed by reaction results and characterizations of FT-IR, UV-Vis and solid NMR. By combining these strategies, Cu/MFI-R catalysts were synthesized for ethanol dehydrogenation, achieving > 90 % ethanol conversion and 95 % acetaldehyde selectivity over the 600 h time on stream test. This work provides a very promising scalable approach for the design of stable Cu-based catalysts in hydrogen-related reactions.