Effect of rectorite on the synthesis of Ag NP and its catalytic activity

• Ag NPs were synthesized greenly with chitosan derivative and rectorite.
• Layers of rectorite were exfoliated.
• Ag NPs were formed on the interlayer and external surface of rectorite.
• Confinement effect of rectorite decreased the diameters of Ag NPs.
• Rectorite enhanced the stability and catalytic activity of Ag NPs.

Silver nanoparticles (Ag NPs) were synthesized greenly into the lamellar space of rectorite (REC) with quaternized carboxymethyl chitosan (QCMC), meanwhile quaternized carboxymethyl chitosan/rectorite/silver bionanocomposite was obtained. Results showed that QCMC and rectorite acted as reducing agent and solid support for Ag NPs, respectively. Exfoliated rectorite (REC) and organic rectorite (OREC) were obtained, simultaneously Ag NPs were formed on their interlayer and external surface. With the confinement effect of rectorite, the average diameters of Ag NPs changed from 45 nm to 22 nm, along with the change in size distributions from 30–65 nm to 18–28 nm, and their shapes changed from sphere to oval. The obtained quaternized carboxymethyl chitosan/rectorite/silver bionanocomposites were made into beads (∼1 mm) to catalyze the reduction of 4-nitrophenol (4-NP), the catalytic rate followed the order: the beads with OREC > those with REC > those without rectorite. The beads with quaternized carboxymethyl chitosan/rectorite/silver bionanocomposites without any treatments still performed well for four consecutive catalytic experiments. Using rectorite to stabilize Ag NPs and get smaller Ag NPs with narrower size distribution may extend the synthesis strategy of other nanoparticles.

Silver nanoparticles were synthesized with chitosan derivative as reducing agent; the stabilizer rectorite decreased the size and size distribution of silver nanoparticle, and enhanced catalytic activity was obtained. Synthesis of quaternized carboxymethyl chitosan/organic rectorite/silver bionanocomposite beads and their catalytic process.Figure optionsDownload as PowerPoint slide