Reconstruction of the ZnAl Mixed Oxides Into the Layered Double Hydroxide Catalysts Active in the Aldol Condensation of Furfural: The Role of ZnO Particles

Lada Dubnová; Rostislav Daňhel; Vendula Meinhardová; Valeriia Korolova; Lucie Smoláková; Tomasz Kondratowicz; Oleg Kikhtyanin; Libor Čapek

doi:10.3389/fchem.2021.803764

Reconstruction of the ZnAl Mixed Oxides Into the Layered Double Hydroxide Catalysts Active in the Aldol Condensation of Furfural: The Role of ZnO Particles

Front Chem. 2022 Jan 14:9:803764. doi: 10.3389/fchem.2021.803764. eCollection 2021.

Authors

Lada Dubnová¹, Rostislav Daňhel¹, Vendula Meinhardová¹, Valeriia Korolova², Lucie Smoláková¹, Tomasz Kondratowicz¹, Oleg Kikhtyanin², Libor Čapek^{1

1}

Affiliations

¹ Department of Physical Chemistry, Faculty of Chemical Technology, University of Pardubice, Pardubice, Czechia.
² Technopark Kralupy VŠCHT Praha, University of Chemistry and Technology Prague, Prague, Czechia.

Abstract

A memory effect is the ability to restore the original, lamellar layered double hydroxide structure. Herein, we have described 1) the changes in the structural and basic properties of ZnAl mixed oxides during their transformation into ZnAl-reconstructed LDHs (RE-LDHs); 2) the extraordinary properties of ZnAl RE-LDHs compared to the original ZnAl LDHs; and 3) the changes of basic properties during the interaction of ZnAl RE-LDHs with atmospheric CO₂. Aldol condensation was selected as probe reaction to prove the catalytic potential of ZnAl RE-LDHs. We have described a target method for preparing ZnAl RE-LDHs with a large number of basic sites. ZnAl RE-LDHs possess significantly higher furfural conversion in the aldol condensation of furfural than MOs. The structural, textural, and basic properties of the studied materials were described by temperature-programmed analysis, X-ray diffraction, N₂ adsorption, temperature-programmed desorption of CO₂, and in-situ diffuse reflectance spectroscopy.

Keywords: Na leaching; ZnAl reconstructed LDHs; aldol condensation of furfural; basic properties; in-situ DRS; structural properties; temperature programmed techniques.