The Relationship between Photoluminescence Emissions and Photocatalytic Activity of CeO2 Nanocrystals

In this work, we focus on understanding the morphology and photocatalytic properties of CeO2 nanocrystals (NCs) synthesized via a microwave-assisted solvothermal method using acetone and ethanol as solvents. Wulff constructions reveal a complete map of available morphologies and a theoretical-experimental match with octahedral nanoparticles obtained through synthesis using ethanol as solvent. NCs synthesized in acetone show a greater contribution of emission peaks in the blue region (similar to 450 nm), which may be associated with higher Ce3+ concentration, originating shallow-level defects wit h i n the CeO2 lattice while for the samples synthesized in ethanol a strong orange-red emission (similar to 595 nm) suggests that oxygen vacancies may originate from deep-level defects wit h i n the optical bandgap region. The superior photocatalytic response of CeO2 synthesized in acetone compared to that of CeO2 synthesized in ethanol may be associated with an increase in long-/short-range disorder wit h i n the CeO2 structure, causing the Egap value to decrease, facilitating light absorption. Furthermore, surface (100) stabilization in samples synthesized in ethanol may be related to low photocatalytic activity. Photocatalytic degradation was facilitated by the generation of center dot OH and center dot O-2- radicals as corroborated by the trapping experiment. The mechanism of enhanced photocatalytic act i v i t y has been proposed suggesting that samples synthesized in acetone tend to have lower e '-h center dot pair recombination, which is reflected in their higher photocatalytic response.

Automated summary

This study investigates the morphology and photocatalytic properties of CeO2 nanocrystals synthesized using microwave-assisted solvothermal method with acetone and ethanol as solvents. The results show that CeO2 synthesized in acetone has more emission peaks in the blue region, possibly due to higher Ce3+ concentration, while CeO2 synthesized in ethanol exhibits a strong orange-red emission, suggesting the presence of oxygen vacancies. CeO2 synthesized in acetone demonstrates superior photocatalytic response compared to that synthesized in ethanol, possibly due to increased disorder in the CeO2 structure, leading to enhanced light absorption.