Effect of the Composition, Nickel Sulfate Addition, and Reduction Temperature on the Morphology of Nickel Oxide through Reduction
The morphology of nickel oxide through reduction under various, controlled conditions was investigated. The reduction process increased the specific surface area of samples from 0.03 to >2 m2/g linearly until ~80 % completion, when it plateaued. Nickel oxide samples with varying concentrations and types of impurities, most notably copper (0.13-5.18 %) and sulfur (0.005-0.36 %) were analyzed to determine their effects on product morphology. The presence of copper impurities had the greatest impact specific surface area, which ranged from 2-6 m2/g between samples after being reduced at 400 °C. The addition of nickel sulfate also increased the specific surface areas by a factor of 1.5-2 by decreasing the rate of sintering. Each type of nickel oxide had a temperature range where the nickel/nickel oxide’s porous network was in a way maintained that depended on the concentration of the sulfate.