Development of Monolithic Hyper-Cross-Linked Polystyrene-Supported Ultrasmall Nano-Ag Catalysts for Enhanced NaBH4-Mediated Dye Degradation.

Synthesizing catalyst supports with appropriate compositions and structures is crucial for reducing the sizes of metal nanoparticles and enhancing their catalytic activities. In this work, a series of monolithic hyper-cross-linked supports (HCP-CC) with hierarchical pores were synthesized. The monolithic structure facilitated easy operation in catalytic reactions, while the composition and structure of HCP-CC could be tailored simultaneously by utilizing the functional cross-linking agent cyanogen chloride. Furthermore, in situ loading of nano-Ag into HCP-CC resulted in the hybrid catalyst HCP-CC-Ag. The synergy of confinement and coordination effect controlled and limited the size of nano-Ag to approximately 3 nm, classifying them as ultrasmall nanoparticles, which ensured outstanding catalytic activity. This hybrid catalyst could improve the reaction rate constant to 0.423 min^-1; it efficiently promoted the degradation of organic dye and exhibited great universality and recyclability, making it a potential heterogeneous catalyst for dye wastewater treatment.