High-Resolution Transmission Electron Microscope images of CeO
NPs and Nanobyk™ NPs in deionized water. A) uncoated CeO2 NPs, B) NB NPs before treatment, C) NB NPs after 4 months aging in daylight (NB-DL), and D) NB NPs after acidic degradation (NB-DA). The inter-reticular distance (dhkl) measured at ~3.2 Å is attributed to the (111) crystalline plane of CeO2. No changes in shape, crystal structure, or CeO2 cluster size were observed by HRTEM.