Interfacial synergy-enhanced catalysis in hierarchically confined poly (glycidyl methacrylate) @ZIF-8@Au composite microspheres for p-nitrophenol degradation

The excellent catalytic performance of noble metal nanoparticles (NMNPs) is often hampered by their tendency to agglomerate and poor recyclability, which significantly limits their large-scale industrial use. To address these challenges, anchoring NMNPs onto porous supports has been proposed as an effective strategy, as it not only suppresses their migration and agglomeration but also enhances their catalytic stability and recyclability through strong metal–support interactions. In this study, novel poly (glycidyl methacrylate) @ZIF-8@Au (PGMA@ZIF-8@Au) composite microspheres were fabricated via three steps: gigaporous PGMA microspheres were first prepared via suspension polymerization, followed by the in-situ growth and subsequent etching of ZIF-8 on their surface, and finally, the confined loading of gold nanoparticles (AuNPs) with three different sizes. This designed structure effectively mitigates issues such as nanoparticle aggregation, detachment, and mass transfer limitations. The hierarchical pores of the PGMA microspheres provide a high specific surface area and abundant active sites, while the rich epoxy rings create an electron-rich environment that facilitates electron transfer to the AuNPs. Moreover, ZIF-8 improves the structural stability and biocompatibility of the composite microspheres and promotes the uniform dispersion of AuNPs. The resulting catalyst achieved 100 % degradation of p-nitrophenol (PNP) within 20 min and maintained a conversion of 84.8 % after ten consecutive cycles. Based on the synergistic effects between the composite and the AuNPs, a plausible catalytic mechanism was proposed. This work offers a promising strategy for designing highly efficient catalysts for environmental remediation.