A two-step method for synthesis of micron sized nanoporous silver powder and ZnO nanoparticles

- Nanoporous micron-sized silver particles via dealloying of Ag-Zn are prepared.
- Mechanical alloying is used to make the Ag-Zn alloy powders.
- Electrolytes are HCl and HCl + AgNO3 solutions under free corrosion condition.
- Recovery of Zn++ ions as ZnO nanoparticles from dealloyed solution is proposed.

Micron-sized nanoporous silver powder with pore size of ∼100-160 nm and specific surface area of ∼4.7-5.5 m2/g was synthesized from three mechanically alloyed Ag-Zn powders (composition: 25, 50 and 75 at.% Zn). Dealloying was carried out at free corrosion conditions in NaOH, HCl and AgNO3 solutions. Both partial and complete dealloying were obtained by suitable choice of electrolyte and time of exposure. Zn in the solution after dealloying was recovered in the form of ZnO nanoparticles with particle size of 55.7 ± 18 nm. The effect of composition and electrolyte on the degree of dealloying was also studied.

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