Theoretical study of size and shell composition effect of TiO2 core-shell mesoporous microsphere on UV absorption effectivity for photocatalytic application

• Published in: Journal of quantitative spectroscopy & radiative transfer 2025-01, Vol.330, p.109246, Article 109246
• Main Authors: Geints, Yury E., Panina, Ekaterina K.
• Format: Article
• Language: English
• Subjects: Core-shell microparticle; Finite elements method; Full-wave electromagnetics; Nanosphere; Optical absorption; Photocatalyst
• ISSN: 0022-4073
• DOI: 10.1016/j.jqsrt.2024.109246

•Full-wave simulation of optical field inside a hollow microsphere randomly self-assembled from multiple TiO2 nanoparticles is presented;.•A unified physical explanation of the published experimental data on the optical activity of titanium-dioxide microcapsules is provided;.•Efficiency of optical absorption by a porous microcapsules with different structural design for enhancing photocatalytic activity is discussed;. Microdispersed photocatalysts based on titanium dioxide (TiO2) in the form of hollow core-shell microspheres (microcapsules) with mesoporous structure are widely demanded in modern critical technologies related to the catalysis of various chemicals, solving environmental problems, and obtaining cheap fuel. To date, a number of experimental works are known, showing that geometrical parameters of microcapsules (size, shell thickness), as well as microstructural composition (nanosized metal additives, additional inner dielectric core- the "yolk") noticeably affect their photocatalytic activity. At the same time, a valuable physical description of the optical properties of porous microcapsules has not been presented in the literature so far. Using the finite element method, we perform a full-wave theoretical simulation of the optical field inside a hollow microsphere whose shell is randomly self-assembled from multiple TiO2 nanoparticles forming an irregular nanoporous structure. We provide a unified physical explanation of the published experimental data on the optical activity of titanium-dioxide microcapsules and show that the existing theoretical models do not always give a correct interpretation of the observed empirical behaviors.