Insight into Oxidation of Lead Powder during Electrodeposition

Pure lead powder can be electrodeposited by reduction of lead ions (Pb 2+ ) in aqueous electrolyte. In this investigation, ultra-fine lead powders with a minimum median diameter of 4.5 μm were electrodeposited in acetate solution. The formation mechanism of lead oxide (PbO) during electrodeposition was proposed. Operation parameters such as pH value, current density, and gelatin had remarkable influence on oxidation degree, median diameter, and current efficiency, which were detailed for the first time. Metallic Pb was formed with strong (111) preferred orientation, and micrography, composition, and structure were characterized. Amorphous PbO was found in as-deposited lead powder, and a gel-layer process was proposed to elucidate the formation of PbO. It was suggested the Pb···OH was the most important intermediate state to form PbO and the gel-layer played the key role in generation of pure lead powder.