Nanoplastic pollution, the final product of plastic waste fragmentation in the environment, represents an increasing concern for the scientific community due to the easier diffusion and higher hazard associated with their small sizes. Therefore, there is a pressing demand for effective strategies to quantify and remove nanoplastics in wastewater. This work presents the “on-the-fly” capture of nanoplastics in the three-dimensional (3D) space by multifunctional MXene-derived oxide microrobots and their further detection. A thermal annealing process is used to convert Ti₃C₂T_x MXene into photocatalytic multi-layered TiO₂, followed by the deposition of a Pt layer and the decoration with magnetic γ-Fe₂O₃ nanoparticles. The MXene-derived γ-Fe₂O₃/Pt/TiO₂ microrobots show negative photogravitaxis, resulting in a powerful fuel-free motion with six degrees of freedom under light irradiation. Owing to the unique combination of self-propulsion and programmable Zeta potential, the microrobots can quickly attract and trap nanoplastics on their surface, including the slits between multi-layer stacks, allowing their magnetic collection. Utilized as self-motile preconcentration platforms, they enable nanoplastics’ electrochemical detection using low-cost and portable electrodes. This proof-of-concept study paves the way toward the “on-site” screening of nanoplastics in water and its successive remediation.

纳米塑料污染是环境中塑料废物破碎的最终产物，由于其较小的尺寸更容易扩散和更高的危害，因此受到科学界越来越多的关注。因此，迫切需要有效的策略来量化和去除废水中的纳米塑料。这项工作展示了多功能 MXene 衍生氧化物微型机器人在三维 (3D) 空间中“动态”捕获纳米塑料及其进一步检测。采用热退火工艺将 Ti ₃ C ₂ T _x MXene 转化为光催化多层 TiO ₂，​​然后沉积 Pt 层并用磁性 γ-Fe ₂ O进行装饰₃纳米粒子。MXene 衍生的 γ-Fe ₂ O ₃ /Pt/TiO ₂微型机器人显示出负光重力，在光照射下产生六自由度的强大无燃料运动。由于自推进和可编程 Zeta 电位的独特组合，微型机器人可以在其表面快速吸引和捕获纳米塑料，包括多层堆叠之间的狭缝，从而实现磁性收集。作为自运动预浓缩平台，它们可以使用低成本和便携式电极实现纳米塑料的电化学检测。这项概念验证研究为“现场”筛选水中的纳米塑料及其后续修复铺平了道路。