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.

中文翻译：

---

TiO2核壳介孔微球尺寸及壳组成对光催化紫外吸收效果影响的理论研究


基于钛白粉 （TiO2） 的微分散光催化剂，以具有介孔结构的空心核壳微球（微胶囊）形式存在，在与催化各种化学品、解决环境问题和获得廉价燃料相关的现代关键技术中被广泛需求。迄今为止，已知的许多实验工作表明，微胶囊的几何参数（大小、壳厚）以及微观结构组成（纳米级金属添加剂、额外的内部介电芯 - “卵黄”）显着影响它们的光催化活性。同时，迄今为止，文献中尚未对多孔微胶囊的光学特性进行有价值的物理描述。使用有限元方法，我们对空心微球内部的光场进行了全波理论模拟，该微球的外壳由多个 TiO2 纳米颗粒随机自组装而成，形成不规则的纳米多孔结构。我们对已发表的关于二氧化钛微胶囊光学活性的实验数据进行了统一的物理解释，并表明现有的理论模型并不总是对观察到的经验行为给出正确的解释。