Abstract α-Ni(OH)2 was electrodeposited from NiCl2 solution by membrane electrolysis method. Various ethanol contents and concentration electrolytes were used to investigate the relevant mechanism. XRD and CV results demonstrated a… Click to show full abstract
Abstract α-Ni(OH)2 was electrodeposited from NiCl2 solution by membrane electrolysis method. Various ethanol contents and concentration electrolytes were used to investigate the relevant mechanism. XRD and CV results demonstrated a preferentially conducted side reaction of Ni2+ to Ni. Ethanol was proved to be effective to poison this reaction. Linear relationships of the product mass and electrodeposition time for electrodepositions in 0.1 M NiCl2 solutions indicated an ignored output of Ni. A four-step mechanism for Ni(OH)2 electrodeposition from the side reaction priority system was proposed. XRD and FT-IR results suggested β-Ni(OH)2 and α-Ni(OH)2 were certain to be synthesized in 0.05–0.1 and 0.2–1.0 M NiCl2 solution. β-Ni(OH)2 formed in these low concentration electrolytes was proved to be prevented by circulating the cathodic electrolyte. Analyses suggested β-Ni(OH)2 formed in the present cases might be either converted from α-Ni(OH)2 under high alkaline digestion or synthesized originally due to the proper ratio of Ni2+ and OH−.
               
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