Preparation and Characterization of Silver Nanoparticles and Their Use in Catalytic Reduction of 4-Nitrophenol

Silver nanoparticles of various sizes were prepared at room temperature using silver nitrate as a precursor, various molar ratios of sodium citrate as a surfactant stabilizing material and sodium borohydride as a reducing agent. The morphology, distribution and sphericity of the particles were assessed in images from a transmission electron microscope (TEM). The sizes of the particles were calculated as being 9, 11 and 14 nm. The effects of the particles’ sizes on the plasmon bands were confirmed by ultraviolet-visible spectra measurements. The prepared samples were applied in photo catalysis of 4-Nitrophenol (4-NP), and the rate constant was determined as 0.05 s-1, 0.0015 s-1 and 0.00021 s-1 for particles of 9 nm, 11 nm and 14 nm, respectively. Due to their high surface energy, the smaller particle sizes were more active in the photo catalytic application.

Synthesis, Characterization and Photocatalytic Application of Different Sizes of Gold Nanoparticles on 4-Nitrophenol

In this work, different sizes of gold nanoparticles were synthesized at room temperature by using trisodium citrate as a surfactant stabilizing agent and sodium borohydride as a reducing agent. Transmission Electron Microscopy (TEM) confirmed that the samples were synthesized in spherical shapes with three different particle sizes: 4 nm, 7 nm and 11 nm. Ultraviolet-visible spectra measurements were used to analyze the way that surface plasmon bands were affected by the different particles sizes. The effect of sphere size on photocatalytic reduction of 4-Nitrophenol was then studied and the rate constant of the reduction was calculated to be 0.014 s-1, 0.0091 s-1 and 0.003 s-1 for particles sizes of 4 nm, 7 nm and 11 nm, respectively. The results obtained indicated that small particles were more active in catalytic reduction due to their high surface energy.