Developing new strategies for fabrication of porous materials with tunable morphology which have fewer environmental impacts is highly desired. Herein, conventional precipitation polymerization of polyurea (PU) synthesis is converted to interfacial polymerization via simple microfluidics and hierarchically porous and uniform PU microspheres (PPM) are prepared by the reaction of toluene diisocyanate and water, eliminating the use of toxic amines and organic solvents. The morphology and porosity of PPM are probed. The size of PPM is controlled by changing the diameter of flow channels of microfluidic device and their pore size and porosity are tuned by optimizing the polymerization conditions. Moreover, palladium (Pd) is immobilized on PPM by impregnation and subsequent reduction approach to get Pd@PPM. The hybrid composite, Pd@PPM, is used for catalytic reduction of toxic Cr⁶⁺ to benign Cr³⁺ by formic acid as a reductant along with sodium format as a promoter in aqueous system. Pd@PPM exhibited high catalytic activity and good stability for Cr⁶⁺ reduction and their large size with high uniformity eased their recovery to reuse them in subsequent Cr⁶⁺ reduction. Porous PU with controllable shape and morphology are rarely available. This work therefore provides new strategy to synthesis PPM with controllable porous morphology and their use as an effective support for catalysis.

非常需要开发用于制造具有可调节形态的多孔材料的新策略，这些材料对环境的影响较小。在此，聚脲（PU）合成的常规沉淀聚合通过简单的微流体转化为界面聚合，并通过甲苯二异氰酸酯和水的反应制备分层多孔且均匀的 PU 微球（PPM），无需使用有毒胺和有机溶剂。研究了 PPM 的形态和孔隙率。PPM 的大小通过改变微流控装置流道的直径来控制，并通过优化聚合条件来调整其孔径和孔隙率。此外，钯（Pd）通过浸渍和随后的还原方法固定在 PPM 上以获得 Pd@PPM。混合复合材料 Pd@PPM，⁶⁺以甲酸为还原剂，钠格式为水体系中的促进剂，可将 Cr ³⁺转化为良性的 Cr ³⁺。Pd@PPM 对 Cr ⁶⁺还原表现出高催化活性和良好的稳定性，并且它们的大尺寸和高均匀性易于回收，以便在随后的 Cr ⁶⁺还原中重新使用。形状和形态可控的多孔聚氨酯很少见。因此，这项工作为合成具有可控多孔形态的 PPM 及其作为催化的有效载体提供了新的策略。