Enhanced photocatalytic VOCs degradation performance on Fe-doped ceria under visible light

In this study, Fe ions doped ceria with two different morphologies were synthesized and their photocatalytic abilities of gaseous acetaldehyde degradation were compared. Interestingly, the photooxidation ability of Fe/CeO2 nanorods (Fe/CeO2-r) for acetaldehyde removal reaches 4.72 times higher than that of pure CeO2 nanorods (CeO2-r). It was found that Fe/CeO2-r and CeO2-r mainly exposed {110} and {100} facets, while CeO2 and Fe/CeO2 with cube morphology mainly exposed {100} facets. The aberration-corrected HAADF-STEM detection for Fe/CeO2-r illustrates isolated dispersion of Fe atom and these Fe atoms were indeed doped into CeO2 crystals via replacing Ce atoms. More importantly, EPR measurement shows that the ·O2− signal intensity of Fe/CeO2-r is stronger than that of other photocatalysts, which means that a large number of active oxygen species are formed during the photocatalytic reaction of volatile organic compounds (VOCs) degradation process. In addition, the dependence of iron ions doping was also analyzed by density functional theory (DFT) calculations and clearly confirmed that Fe/CeO2 {110} is more conducive to the acetaldehyde absorption and carbon dioxide desorption than Fe/CeO2{100}, which is greatly agreement with the experimental results. In a word, the photocatalytic acetaldehyde pollutions degradation efficiency of ceria-based photocatalysts can be improved by Fe ions doping which provides a feasible strategy for improving the performance of other semiconductor photocatalyst materials.