Facet-engineered CeO2 with Cu single atom drives photocatalytic selective oxidation of 5-hydroxymethylfurfural

Abstract

The crystal facet of CeO2 is crucial in governing the catalytic performance. However, studies on the relationship between the photocatalytic oxidation performance of CeO2 and its crystal facets are scarce. Herein, we synthesized a series of CeO2. Through loading Cu single atom (Cu/CeO2), the facet effects of crystal facets on the photocatalytic selective oxidation were studied systematically via employing the selective oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran as a model. Because the (110) facet's superior electron transfer efficiency, are feasible for absorbing 5-hydroxymethylfurfural, eliminating α-H, and desorbing 2,5-diformylfuran, the selectivity of Cu/CeO2-nanorod (Cu/CeO2-R) with (110) facet (93.34%) is much higher than that of Cu/CeO2-nanocube (Cu/CeO2-C) with (100) facet (32.22%) and Cu/CeO2-nanooctahedra (Cu/CeO2-O) with (111) facet (15.20%). The DFT calculation shows that the Cu 3d has orbital hybridization with Ce 5d and 4f, which provides a favorable pathway for electron transfer. This work delves into the facet-performance relationship during the photocatalytic process.