Mechanistic Investigation of Enhanced Catalytic Selectivity toward Alcohol Oxidation with Ce Oxysulfate Clusters.

Ceria-based materials have been highly desired in photocatalytic reactions due to their redox properties and strong oxygen storage and transfer ability. Herein, we report the structures of one CeCe oxysulfate cluster and four MCe clusters (M = Cu, Ni, Co, and Fe) with the same Ce core. As noted, single-crystal X-ray diffraction confirmed the structures of CeCe and the MCe series, while Raman spectroscopy indicated an increase in oxygen defects upon the introduction of Cu and Fe ions. The clusters catalyzed the oxidation of 4-methoxybenzyl alcohol under ultraviolet light. CuCe and FeCe exhibited enhanced reactivity compared to CeCe and improved aldehyde selectivity compared to control experiments. In comparison with their homogeneous congeners, the CeCe/MCe clusters altered the location of radical generation from the bulk solution to the clusters' surfaces. Mechanistic studies highlight the role of oxygen defects and specific transition metal introduction for efficient photocatalysis. The mechanistic pathway in this study provides insight into how to select or design a highly selective catalyst for photocatalysis.