Electrodeposition of catalytically active nickel powder from sulphate baths: Effect of some operating variables

Fine-grained nickel powder has been successfully electrodeposited from a very dilute all-sulphate bath of the composition 0.0125 moll⁻¹ NiSO₄ · 7H₂O, 0.23 moll⁻¹ (NH₄)₂SO₄, 0.1 moll⁻¹ H₃BO₃ and 0.07moll⁻¹ Na₂SO₄ · 10H₂O. The current efficiency of the deposition process and the surface morphology, as well as the catalytic activity of the electrodeposited nickel powder towards the decomposition of 0.4% H₂O₂ solution, were found to be fundamentally influenced by the operating variables pH, current density and duration of the electrolysis. X-ray diffraction studies revealed that the nickel powder is free from oxide and hydroxide contaminations. Under the optimum operating conditions (pH = 7.7 j = 13.3 A dm⁻² and t = 10 min) the selected bath produced a nickel deposit characterized by catalytic activity approaching 100% with a deposition efficiency around 18%.