Influence of Temperature on the Formation of Silver Nanoparticles by using a Seed-Free Photochemical Method under Sodium-Lamp Irradiation.
Silver nanoparticles can be prepared by using a seed-free photo-assisted citrate reduction method under the irradiation of a sodium lamp. Under the same irradiation intensity, bath temperatures are crucial in influencing the reaction rate, morphologies of final products, and shape evolution of the silver nanostructures. For example, when the bath temperature is 80 °C, the product yields of silver nanoplates, nanorods, and nanodecahedra are 38±6 %, 35±10 %, and 12±8 %, respectively. However, when the bath temperature is 30 °C, the product yields of silver nanoplates, nanorods, and nanodecahedra are 6±3 %, 0 %, and 83±16 %, respectively. Time-dependent UV/Vis spectra and TEM images show that silver nanoplates were formed at the earlier reaction stage and greatly decreased in amount at the later stage when the bath temperatures are less than or equal to 40 °C. This indicates that the silver nanoplates, which can be regarded as intermediates, are kinetically favored products. They are not thermodynamically favored products at these relatively low bath temperatures. The SERS spectra of crystal violet (CV) show that all the silver colloids synthesized at various temperatures exhibit good enhancement factors and that the colloids prepared at lower bath temperatures have a higher enhancement factor.
Department of Applied Chemistry, National Chiayi University, 300 Sha-Fu Road, Chiayi City, 60004, Taiwan.
Yen-Ling
YL
Kuo
Department of Applied Chemistry, National Chiayi University, 300 Sha-Fu Road, Chiayi City, 60004, Taiwan.
Tzong-Yuan
TY
Juang
Department of Applied Chemistry, National Chiayi University, 300 Sha-Fu Road, Chiayi City, 60004, Taiwan.
Shi-Hise
SH
Chang
Department of Applied Chemistry, National Chiayi University, 300 Sha-Fu Road, Chiayi City, 60004, Taiwan.
Chin-Ming
CM
Tsai
Department of Applied Chemistry, National Chiayi University, 300 Sha-Fu Road, Chiayi City, 60004, Taiwan.
Yen-Shang
YS
Lai
Department of Applied Chemistry, National Chiayi University, 300 Sha-Fu Road, Chiayi City, 60004, Taiwan.
Li-Chen
LC
Yang
Department of Applied Chemistry, National Chiayi University, 300 Sha-Fu Road, Chiayi City, 60004, Taiwan. clhuang@mail.ncyu.edu.tw.
Cheng-Liang
CL
Huang
D053758:Nanoparticles; D010777:Photochemistry; D012834:Silver / Q000737:chemistry*; D012964:Sodium / Q000737:chemistry*; D013696:Temperature
D012834:Silver; D012964:Sodium
citrate reduction method; nanoparticles; photochemistry; seed-free; silver