Catalysts that can rapidly degrade tetracycline (TC) in water without introducing secondary ion pollution have always been challenging. Herein, a cobalt-based catalyst (CoO_x@P-C) is prepared so that CoO_x quantum particles (5–10 nm) are uniformly distributed on a linear substrate, and the outer layer is covered with a shell (P-C). The quantum particles of CoO_x provide many active sites for the reaction, which ensures the efficient degradation effect of the catalyst, and 30 mg/L TC can be completely degraded in only 5 min. The shell of the quantum particles' outer layer can effectively reduce ions' extravasation. The combination of the shell-like structure and the linear substrate greatly enhances the catalysis's stability and ensures that the catalyst is prepared into a film for practical application. The high catalytic activity of CoO_x@P-C is mainly due to the following factors: (1) Uniformly distributed ultra-small nanoparticles can provide many active sites. (2) The microenvironment formed by the core-shell structure enhances not only catalytic stability but also provides the driving force to improve the reaction rate. (3) The composite of CoO_x and P-C core-shell structure can accelerate electron transfer and generate many reactive oxygen species in a short time, which makes TC degrade extremely rapidly.

能够快速降解水中四环素（TC）而不引入二次离子污染的催化剂一直是一个挑战。在此，制备了一种钴基催化剂（CoO _x @PC），使CoO _x量子粒子（5-10 nm）均匀分布在线性基底上，外层覆盖有壳（PC）。_{CoO x}的量子粒子为反应提供了许多活性位点，保证了催化剂的高效降解效果，30 mg/L TC仅需5 min即可完全降解。量子粒子外层的外壳可以有效减少离子的外渗。壳状结构与线性基质的结合大大增强了催化剂的稳定性，保证了催化剂制备成薄膜的实际应用。_{CoO x} @PC的高催化活性主要归因于以下因素：（1）均匀分布的超小纳米粒子可以提供许多活性位点。(2)核壳结构形成的微环境不仅增强了催化稳定性，而且为提高反应速率提供了驱动力。_{(3) CoO x}的复合物而PC核壳结构可以加速电子传递，并在短时间内产生大量活性氧，使得TC降解速度极快。