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A novel, efficient and durable ZrP@PDA/Ag nanocatalyst was prepared via the facile reduction and deposition of silver nanoparticles (AgNPs) on two dimensional (2D) α-zirconium phosphate (ZrP) nanosheets using bio-inspired dopamine chemistry. The formation, adhesion and dispersion of AgNPs were confirmed by the full morphological and structural characterizations including SEM, TEM, FTIR, TGA, WXRD, and XPS. This ZrP@PDA/Ag nanocatalyst was evaluated by the reduction of 4-nitrophenol into 4-aminophenol, utilizing UV-vis absorption spectroscopy to monitor the reaction solution with a trace silver content of 0.125 μg mL−1. ZrP@PDA/Ag exhibits a superior catalytic activity compared with other noble metal nanocatalysts due to its high turnover frequency of 32.36 min−1 at room temperature without stirring, which is as high as almost 10 times that of the reported nanocatalysts using 2D graphene and silica supports. Furthermore, due to the excellent catalytic recyclability of ZrP@PDA/Ag it has very promising prospects in the treatment of organic pollutants in water. [ABSTRACT FROM AUTHOR]

We disclose an economical and metal-free catalyst system of (thio)ureas/organic bases for effective fully alternating copolymerization of epoxides and anhydrides, which remains a challenge in sustainable polyester synthesis. A series of commercial (thio)ureas and organic bases were employed as dual catalysts to optimize the activity, and the results indicate that the (thio)ureas with higher basicity paired with quaternary onium salts show higher activity. Particularly, the U1/PPNCl pair shows extremely high TOF (456 h−1) toward the ring-opening alternating copolymerization of cyclohexane oxide with phthalic anhydride, which is comparable to the activity of metal-based complex catalysts. Structurally diverse polyesters with high ester linkages (99%) and various glass transition temperatures (ranging from −8 to 133 °C) can be obtained by coupling of various renewable epoxides and anhydrides. What's more, structural analysis of the resultant polymers and the interactions between the monomers and the dual catalysts confirmed by 1H NMR reveal that the (thio)urea can act as a bifunctional catalyst, which activates both the initiating chain end and the monomer through H-bonding in the (thio)urea/PPNCl catalyst system, resulting in high activity. [ABSTRACT FROM AUTHOR]