engleski

Ceria-zirconia-based high entropy oxides as catalysts for pinacol-type reactions

Novel high entropy oxides (HEOs) were synthesized in nanocrystalline powder form using a modified citrate sol-gel route. These compounds were further structurally characterized using powder X- ray diffraction (PXRD), Raman spectroscopy, scanning electron microscopy coupled with energy- dispersive X-ray spectroscopy (SEM-EDS), high resolution transmission electron microscopy (HRTEM), BET physisorption measurements and thermogravimetric analysis. HEOs were further used as catalysts for efficient Lewis acid-catalyzed direct conversion of aldehydes to 1, 2-diketones in liquid phase. The synergistic effect of various cations incorporated in the same oxide structure (framework) is partially responsible for the efficiency of multi-cationic materials compared to corresponding single-cation oxide forms. Furthermore, a clear, linear relationship between the Lewis acidity and the catalytic activity of the HEOs is observed. Due to the developed strategy, exclusively diketone selective, recyclable, versatile heterogeneous catalytic transformation of aldehydes can be realized under mild reaction conditions.

1, 2-diketone selective conversion of aldehydes ; ceria ; ceria-zirconia-based multimetallic oxides ; high entropy oxides

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