Restacking or aggregation inhibition of MXene nanosheets is crucial to the maintenance of their excellent electrochemical performance during use. In this study, a positively charged surfactant is inserted into the MXene nanolayers through a simple self-assembly process based on electrostatic interaction, producing a MXene/surfactant complex with enlarged interlayer spacing. Then 3D MXene-based porous structure could be prepared by the facile and low-cost breath figure method, in which MXene/surfactant complex is used as a casting material, therefore the inhibition of restacking or aggregation and increase of surface area at multiscale are realized in one system at the same time. Benefiting from the high conductivity of MXene and increased surface area of 3D porous structure that can provide massive active sites and facilitate the electrolyte infiltration and ion or electron access, enhanced electrochemical performance, for instance, electrochemical sensing of dopamine (DA) is shown. A low detection limit of 36.8 nM with excellent anti-interference, reproducibility, repeatability and long-term stability is realized. Good accuracy for DA detection in real biological samples is also confirmed by determining DA concentration in complex human urine samples. More importantly, porous structure such as pore size, uniformity, order and porosity can be adjusted through tuning the fabrication conditions, thereby regulating its electrochemical properties. This work not only provides a high-performance electrode for electrochemical sensing, but also offers a simple and practical strategy for the construction of 3D porous MXene film that holds great potential in electromagnetic interference shielding, supercapacitors and batteries.

MXene 纳米片的重新堆叠或聚集抑制对于在使用过程中保持其优异的电化学性能至关重要。在这项研究中，通过基于静电相互作用的简单自组装过程将带正电的表面活性剂插入到 MXene 纳米层中，产生具有更大层间距的 MXene/表面活性剂复合物。然后可以通过简单且低成本的呼吸图方法制备基于 3D MXene 的多孔结构，其中 MXene/表面活性剂复合物作为浇注材料，从而实现了在多尺度上抑制重新堆叠或聚集和增加表面积同时在一个系统中。受益于 MXene 的高电导率和 3D 多孔结构增加的表面积，可以提供大量的活性位点并促进电解质的渗透和离子或电子的进入，从而提高电化学性能，例如多巴胺 (DA) 的电化学传感。实现了 36.8 nM 的低检测限，具有出色的抗干扰性、重现性、重复性和长期稳定性。通过确定复杂的人类尿液样本中的 DA 浓度，也证实了在真实生物样本中检测 DA 的良好准确性。更重要的是，可以通过调整制备条件来调节孔径、均匀性、有序度和孔隙率等多孔结构，从而调节其电化学性能。