1808 Microsc. Microanal. 27 (Suppl 1), 2021 doi:10.1017/S1431927621006619 © Microscopy Society of America 2021 Electron Microscopy Contributions to Producing an Effective Germicide Photocatalyst Rodney Herring, Shae Pazdernick, Zhina Hadisi, Mohsen Akabari, Elaine Humphrey and Vahid Moradi University of Victoria, Victoria, British Columbia, Canada The information obtained from Scanning Electron Microscopy (SEM) and High Resolution Transmission Electron Microscopy (HRTEM) of a Fe doped TiO2 photocatalytic crystals played a significant role to enable their efficient activation using safe, visible light and to verify their germicide mechanism against bacteria now being tested against COVID-19 virus. When activated using visible light, these crystals produce hydroxyl radicals, OH:, one of the strongest oxidants, able to kill bacteria effectively and efficiently upon contact. Prior to this work, ultraviolet (UV) was necessary to activate the TiO2 crystals severely limiting their disinfecting applications as UV is carcinogenic and doesn’t pass through water nor glass. Resolving and understanding this problem, as we show here, paved the way towards applying them to keep surfaces germ free, theoretically forever since the crystals are a catalyst, and using the crystals to clean water reducing our environmental impact on rivers, lakes and oceans, helping to prevent red tides and reduce the acidification of our waters. HREM imaging of freshly made Fe doped TiO2 crystals revealed the existence of a thin amorphous contamination layer on their surfaces (Figure 1) sometimes just a couple atoms thick. Cleaning the surface of the Fe doped TiO2 nanoparticles using HCl acid removed the surface contamination resulting in the atomic planes of the Fe doped TiO2 crystals to extend to the surface. The surface cleaning significantly improved the transport of the electrons and positive holes to the surface where they create hydroxyl radicals and super oxygen radicals from water improving the disinfecting ability and degradation efficiency of the water cleaning process [1, 2]. Crystals applied to surfaces kept them germ free (Figure 2a) lasting for several weeks. Afterwards, reactivation of the crystals on soiled surfaces continued upon cleaning the surface of spilt food and drink. Mixing the crystals with E-coli in solution and exposing them to ambient light reduced cell survival to zero after 4 hours (Figure 2b). The mechanism by which the crystals killed E-coli was revealed by SEM showing lysed cell membranes at points of contact with the crystals (Figure 2c). The degradation process is indescriminant, cleaning all germs on surfaces as wells eliminating al contaminants in wastewater including the ammonia necessary to reduce red tides. Tests against the COVID-19 virus on many types of surfaces are now being conducted. Grants from NSERC Discovery and Engage, CFI and BCKDF are greatly appreciated. https://www.cambridge.org/core/terms. https://doi.org/10.1017/S1431927621006619 Downloaded from https://www.cambridge.org/core. IP address: 3.238.179.163, on 05 Nov 2021 at 00:45:15, subject to the Cambridge Core terms of use, available at