Electrochemical Syntheses of Binary Silver Oxides

The electrolytic syntheses of the oxides AgjOj and AgjO are carried out in a simple beaker containing the electrolyte. Only for the synthesis of AgO a closed cell is required, because in the latter case electrolysis has to be performed at a temperature of about 100°, which is close to the boiling point of the electrolyte. 

The stock solution is prepared as follows. A solution containing 1.00 + 0.05 mol/L Ag is prepared by dissolving silver perchlorate monohydrate (225.3 g, 1.0 mol) in one liter of doubly distilled water. The solid salt and the aqueous solution are both stable and easy to handle. Alternatively, the stock solution may be prepared by adding an excess of silver(l) carbonate to aqueous perchloric acid. Silver hexafluorophosphate or tetraffuoroborate, which may also be used for the synthesis of Ag203, are difficult to prepare in sufficient purity. 

The products are isolated as follows. After electrolysis the anode covered with product crystals is removed cautiously together with the cap of the cell. Both are transferred to a 20-mL test tube filled with cold, doubly distilled water. The crystals are removed mechanically from the electrode and sampled using a small filter crucible. After washing with cold, doubly distilled water the crystals are dried in vacuum ( — 1 mbar) for at least 10 min, and, depending on the total mass of the product, up to several hours. 

For collecting and drying the samples we have used a special apparatus as shown in Fig. 1. The crystals can be transferred through the open ground 

Scale-up of the procedures is possible by increasing the volume of the electrolyte, while maintaining current density and the time of electrolysis. Consequently, a larger volume of electrolyte will require an anode with a large surface. 

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