Development\nof Monolithic Hyper-Cross-Linked Polystyrene-Supported\nUltrasmall Nano-Ag Catalysts for Enhanced NaBH<sub>4</sub>‑Mediated\nDye Degradation

Synthesizing\ncatalyst supports with appropriate compositions\nand\nstructures is crucial for reducing the sizes of metal nanoparticles\nand enhancing their catalytic activities. In this work, a series of\nmonolithic hyper-cross-linked supports (HCP-CC) with hierarchical\npores were synthesized. The monolithic structure facilitated easy\noperation in catalytic reactions, while the composition and structure\nof HCP-CC could be tailored simultaneously by utilizing the functional\ncross-linking agent cyanogen chloride. Furthermore, <i>in situ</i> loading of nano-Ag into HCP-CC resulted in the hybrid catalyst HCP-CC-Ag.\nThe synergy of confinement and coordination effect controlled and\nlimited the size of nano-Ag to approximately 3 nm, classifying them\nas ultrasmall nanoparticles, which ensured outstanding catalytic activity.\nThis hybrid catalyst could improve the reaction rate constant to 0.423\nmin<sup>–1</sup>; it efficiently promoted the degradation of\norganic dye and exhibited great universality and recyclability, making\nit a potential heterogeneous catalyst for dye wastewater treatment.