Chemistry Forum

How to prepare colloidal silver through chemical reduction, I have a
0.355L / 0.1M silver nitrate solution (AgNO₃) and sodium citrate tribasic dihydrate (C₆H₅Na₃O₇·2H₂O)???
Pls help me

To prepare colloidal silver through chemical reduction using the given reagents, you'll need to follow these steps:
Prepare Silver Nitrate Solution:
Measure 0.355 liters of the 0.1 M silver nitrate (AgNO₃) solution. This solution contains silver ions (Ag⁺) that will be reduced to form colloidal silver.
Prepare Sodium Citrate Solution:
Dissolve sodium citrate tribasic dihydrate (C₆H₅Na₃O₇·2H₂O) in water to prepare a sodium citrate solution. The concentration of this solution will depend on the desired properties of the colloidal silver.
Combine Solutions:
Mix the silver nitrate solution with the sodium citrate solution in a suitable container. The ratio of silver nitrate to sodium citrate will influence the size and stability of the colloidal silver particles.
Reduce Silver Ions:
Add a reducing agent to the combined solution to reduce silver ions (Ag⁺) to elemental silver (Ag⁰). Common reducing agents used for this purpose include citric acid, glucose, or ascorbic acid (vitamin C).
Stir and Heat (Optional):
If necessary, stir the solution and heat it gently to facilitate the reduction process. Avoid boiling the solution, as excessive heat can affect the properties of the colloidal silver.

A two-step reduction produces silver colloids with homogeneous shape and size. Small silver particles are formed by rapidly reducing silver nitrate with sodium citrate at 100°C and then growing at 92°C. Transmission electron microscopy, ultraviolet-visible absorption spectrophotometry, zeta-potential measurements, and Ag+ concentration analysis are used to characterize the chemical mechanisms and silver colloids that occur. The surface-enhanced Raman scattering (SERS) activity of silver colloids is next examined, with crystal violet (CV) serving as a SERS probe. The silver colloids are homogenous in shape and size, with consistent SERS activity. The silver particles have an average size of 47 nm (14% relative standard deviation), whereas the average sizes of silver colloids generated at 100°C and 92°C are 41 (30%) and 71 nm (33%), respectively.