期刊
SN APPLIED SCIENCES
卷 1, 期 6, 页码 -出版社
SPRINGER INTERNATIONAL PUBLISHING AG
DOI: 10.1007/s42452-019-0586-1
关键词
Silver nanoparticles; Starch; Photochemical synthesis; Photochemical kinetic
资金
- CNPq [308038/2012-6]
- CAPES/Pro-Amazonia [3333-047/2012]
- FAP-DF [0193.000829/2015]
In this contribution, we report an original photochemical method and its mechanism, in which Ag nanoparticles (AgNPs) are formed in the presence of starch. AgNO3/potato starch aqueous suspensions are irradiated (254 nm, 8 W) at room temperature and the Ag+/starch ratio can be varied to tune the size of AgNPs. The evolution of the AgNPs plasmon resonance band during the reaction is monitored by UV-Vis spectroscopy and evidences that AgNPs are formed in a two-stage process combining nucleation and growth, with the nucleation being controlled by the amount of added starch. Moreover, infrared and Raman spectra indicates that starch undergoes oxidation simultaneously to Ag+ reduction, even though starch alone is not capable of reducing Ag+ at an appreciable rate and UV irradiation is essential to produce sizeable amounts of AgNPs. Transmission electron microscopy reveals that AgNPs are nearly spherical with diameters ranging between 13 and 8 nm. The AgNPs/starch suspensions exhibit hydrodynamic diameters between 150 and 200 nm and zeta potentials very close to zero. Since AgNPs/starch suspensions are very stable over time, the colloidal stability is ensured by the steric hindrance imposed by starch rather than electrostatic repulsion. [GRAPHICS]
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