Interfacial assembly of mussel-inspired polydopamine@Ag core-shell nanoparticles as highly recyclable catalyst for nitroaromatic pesticides degradation.

With the abundant use of pesticides in agriculture and grassland farming, water contamination unavoidably occurs due to the leaching of pesticide residues into environment. Now, most of the research on degradation of nitroaromatic pesticides residues has focused on nano catalysis-based method, however, effective post-reaction separation and recycling of the tiny nanocatalysts is also a significant technological challenge to be addressed. Herein, we report a simple and versatile strategy for the construction of efficient and recyclable catalysts of polydopamine (PDA)@Ag/polystyrene (PS) films for degradation of pesticides based on multi-purpose PDA microspheres inspired by mussel adhesion. The PDA not only functioned as a scaffold, a reductant as well as a stabilizer for the formation and dispersions of Ag NPs in situ, but also served as an adhesive layer between the nanocatalysts and the substrate. The obtained PDA@Ag/PS films were evaluated for the first time against the catalytic degradation of pendimethalin. Most importantly, the recovery of catalysts can be easily realized by simply pulling out PS substrate from the reaction mixture and the catalytic activity of the nanofilms was found to be equally efficient for seven catalytic cycles. Considering their excellent catalytic activity and recyclability in the degradation of nitroaromatic pesticides, the PDA@Ag/PS films have great potential applications in the fields of environment protection, soil contamination remediation, and sewage treatment. Also, by virtue of the remarkable reducing and stabilizing ability and adhesive versatility of PDA, this approach can be extended to the deposition of various metals and semiconducting NPs, which can be stably anchored on a diverse range of solid substrates regardless of physiochemical and morphology.