A novel core/shell C-TiO₂/CoTiO₃ type II heterojunction was successfully synthesized via a direct calcination method by using MIL-125/Co core-shell nanocakes as a sacrificial template and precursor. In the calcination process, the organic ligand in MIL-125 acts as an in-situ carbon doping source to form a carbon-doped TiO₂ core (C-TiO₂). At the same time, CoTiO₃ nanoparticles are formed on the surface of C-TiO₂ by an in-situ solid-state reaction between the C-TiO₂ and Co²⁺ shell of MIL-125/Co. Due to such delicate core/shell structural features, carbon doping and type II heterojunctions, C-TiO₂/CoTiO₃ core/shell composites can effectively harvest visible light, facilitate the interfacial separation and suppress the recombination of photogenerated electron-hole pairs, leading to the remarkable photocatalytic activity for removal of ciprofloxacin (CIP). In particular, C-TiO₂/CoTiO₃-3 exhibits the best photocatalytic degradation activity of CIP with a degradation efficiency of 99.6% and a total carbon content removal percentage of 76% under visible-light illumination for 120 min. In addition, the proposed photocatalytic mechanism study illustrated that the main radical species in the photocatalytic degradation of CIP using C-TiO₂/CoTiO₃ as the photocatalyst is •OH. This work provides a new approach and insight for synthesizing core/shell heterojunction-based photocatalysts for various applications.

以MIL-125 / Co核壳纳米饼为牺牲模板和前驱体，通过直接煅烧法成功合成了新型核/壳C-TiO ₂ / CoTiO ₃ II型异质结。在煅烧过程中，MIL-125中的有机配体充当原位碳掺杂源，以形成碳掺杂的TiO ₂核（C-TiO ₂）。与此同时，CoTiO ₃形成C-TiO 2的表面上的纳米颗粒₂由C-TIO之间的原位固态反应₂和Co ²⁺ MIL-125 /钴的壳。由于这种精细的核/壳结构特征，碳掺杂和II型异质结，C-TiO ₂ / CoTiO_3种核/壳复合材料可以有效地收集可见光，促进界面分离并抑制光生电子-空穴对的重组，从而具有显着的光催化活性，可去除环丙沙星（CIP）。特别地，C-TiO ₂ / CoTiO ₃ -3在可见光照射120分钟下表现出CIP的最佳光催化降解活性，其降解效率为99.6％，总碳含量去除率为76％。此外，所提出的光催化机理研究表明，C-TiO ₂ / CoTiO ₃对CIP的光催化降解中的主要自由基种类因为光催化剂是•OH。这项工作为合成基于核/壳异质结的光催化剂提供了一种新的方法和见识，可用于各种应用。