Abstract: Shape-controlled silver nanoparticles (Ag NPs) were prepared in a well-dispersed mode on the active imprinting sites of chitosan-TiO2 adsorbent (CTA) by means of bioaffinity adsorption and TiO2 photocatalysis. Nontoxic hydrogen peroxide (H2O2) was used as a suitable etching reagent in our production of shape-controlled Ag NPs, since it could regulate the TiO2 photocatalysis and accelerate the generation of O2. With the same amount of H2O2 addition, silver nanocubes, nanospheres and truncated triangular nanoplates were individually obtained on the surface of CTA under UV irradiation by facilely adjusting the initial Ag+ concentration. The FE-SEM, XRD and UV-visible characterizations confirmed single crystal Ag NPs with different shapes loaded on CTA. The mechanism for the formation of shape-controlled Ag NPs was discussed based on a photocatalytic reaction system. As an example of applications of the Ag NPs, we tested the biocidal properties, and silver nanocubes exhibited the highest antibacterial activity. Our research provided a simple synthesis for shape-regulated Ag NPs steadily loaded on CTA. It might moreover be a guide in preparing metal nanocrystals monodispersely immobilized on chemical substrates
Author keywords: silver nanoparticle, Shape-controlled systhesis, chitosan-TiO2 adsorbent, Bioaffinity adsorption, Photocatalysis

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