In situ decoration of Ag nanoparticles on chitosan spheres with enhanced photo-catalytic activity

In this study, Ag-decorated chitosan (Ag-chitosan) spheres were synthesized through in situ decoration of Ag nanoparticles (NPs) on the surface of chitosan spheres via a hydrothermal route. Chitosan spheres were synthesized through emulsification of chitosan solution in the paraffin oil followed by cross-linked with glutaraldehyde. They were then soaked in the solution of AgNO₃ and subject to a hydrothermal treatment at 120°C to produce Ag-chitosan spheres. SEM observation showed that the Ag-chitosan spheres were spherical in shape with the diameter of 5-20 µm. An EDS spectrum showed that the Ag-chitosan spheres were rich in C, O, and Ag elements. After incubation in the solution of 4-nitrophonol and NaBH₄, Ag-chitosan spheres showed good photo-catalytic activity for reduction of 4-nitrophonol. (paper)