Microfluidically Assisted Construction of Hierarchical Multicomponent Microparticles for Short Intermediate Diffusion Paths in Heterogeneous Catalysis

The construction of hierarchical nanoparticle assemblies with well-defined surface control and stability has captured enormous attention because of their fascinating coupled properties and enhanced interfacial ability useful for catalysis, biomedical, and sensing applications. Progressively, the present work here introduces the preparation progress of hierarchical multicomponent assembly particles in which multilayered nanoparticles and microparticles have been fabricated via electrostatic surface interaction. Various types of metal nanoparticles were uniformly deposited on the surfaces of charged/swellable polymer nanoparticles, and the further deposition of these composite nanoparticles has been selectively applied on the surfaces of hydrogel microparticles. The fabrication procedure is based on microfluidic technology, which provides the advantages of homogeneous size distribution of particles and highly precise interfacial interaction. Layer-by-layer technology was used to combine oppositely charged nanoparticles through electrostatic interaction. A potential catalysis application is investigated by the reductive bleaching of an azo dye by sodium borohydride. The results show that the reaction rate is enhanced by the effect of composite particles. Because this fabrication method and the fabricated assembly particles are robust, showing potential in heterogeneous catalysis, the other types of metal nanoparticles can also be loaded onto the polymer microparticles, which may provide a platform to explore novel applications in future needs.