The world's oceans are polluted by a continuous inflow of plastic. Plastic fragments finally into microplastic, which can be taken up, for example by plankton, and subsequently by the entire ocean food web. An approach to reduce plastic pollution constitutes the accelerated microplastic degradation in marine environments. TiO₂ (anatase) is commonly used as an oxidative photocatalyst and well known to catalyze the degradation of organic compounds upon UV irradiation.

In this study, a selective activation of TiO₂ (anatase) particles encapsulated by Ca- or Sr-polyphosphate is presented. The TiO₂ polyphosphate core-shell particles are envisaged as additives in plastic products. The highly concentrated cations from seawater, viz. Na⁺ and Mg²⁺, displace the Ca²⁺ or Sr²⁺ cations from the polyphosphate shell. As a result, the polyphosphate coating dissolves and thus the photocatalytically active TiO₂ core is released. The stability of the TiO₂ polyphosphate particles in potable water and the seawater activated disintegration of methylene blue, methyl methacrylate, terephtalic acid, and poly(vinyl alcohol) was shown. It has been demonstrated, that the sweetwater stable polyphosphate coating degrades in the presence of seawater, which could be monitored by the activation of the TiO₂ (anatase) photocatalyst.

持续不断的塑料流入污染了世界海洋。最终塑料碎片变成微塑料，例如可以被浮游生物吸收，然后被整个海洋食物网吸收。减少塑料污染的方法构成了海洋环境中加速的微塑料降解。TiO ₂（锐钛矿）通常用作氧化性光催化剂，众所周知，它可在UV辐射下催化有机化合物的降解。

在这项研究中，提出了由Ca-或Sr-多磷酸盐封装的TiO ₂（锐钛矿）颗粒的选择性活化。设想将TiO ₂多磷酸盐核-壳颗粒用作塑料产品中的添加剂。来自海水的高浓度阳离子，即。Na ⁺和Mg ^2+可以从多磷酸盐壳中置换出Ca ²⁺或Sr ²⁺阳离子。结果，聚磷酸盐涂层溶解并且因此释放了光催化活性的TiO ₂核。TiO ₂的稳定性显示了饮用水中的多磷酸盐颗粒和海水激活了亚甲基蓝，甲基丙烯酸甲酯，对苯二甲酸和聚乙烯醇的崩解。已经证明，在海水的存在下，对甜水稳定的多磷酸盐涂层会降解，这可以通过TiO ₂（锐钛矿）光催化剂的活化来监测。