Synthesis of chitosan/silver nanocomposites by phase inversion with the assistance of carbon dioxide

Int J Biol Macromol. 2021 Oct 21:S0141-8130(21)02273-X. doi: 10.1016/j.ijbiomac.2021.10.115. Online ahead of print.ABSTRACTCarbon dioxide (CO2) assisted synthesis of water-soluble silver nanoparticle with a narrow particle size distribution is reported here based on the phase-inversion procedure. Bio-derived chitosan (CS) is used to stabilize the metal nanoparticles according to its abundant functional groups. Formic acid is employed as both a solvent (for the polymer) and a reductant for in-situ reducing the silver precursor along with the solvent evaporation. CO2 is utilized to combine with the amino groups of CS, reducing the viscosity of chitosan/formic acid solution and limiting the formation of hydrogen bonds. This promotes the stabilization and reduction efficiency of silver nanoparticles. In particular, 100% of Ag metal nanoparticles with the size of 7.5 ± 2.3 nm is successfully synthesized with the assistance of CO2. Interestingly, the synthesized CS/Ag nanocomposites are water-soluble owing to the formation of carbamate groups. This water-soluble silver nanoparticle presents an exceptional performance in the selective reduction of 4-nitrophenol, where the turnover frequency (TOF = 599 h-1) is even double with respect to the CO2 free system.PMID:34688679 | DOI:10.1016/j.ijbiomac.2021.10.115
Source: International Journal of Biological Macromolecules - Category: Biochemistry Authors: Source Type: research