Effect of SeO2 on the morphology of electrodeposited manganese

• Published in: Journal of applied electrochemistry Vol. 50; no. 12; pp. 1291 - 1299
• Main Authors: Pérez-Garibay, R., Rojas-Montes, J. C., Bello-Teodoro, S., Flores-Álvarez, J. M.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.12.2020; Springer Nature B.V
• Subjects: Ammonium sulfate; Anion exchanging; Anolytes; Chemistry; Chemistry and Materials Science; Crystal growth; Dissolution; Electrochemistry; Electrodeposition; Grain size; Hydrogen evolution; Industrial Chemistry/Chemical Engineering; Manganese dioxide; Metal plates; Morphology; Nuclei; Nuclei (cytology); Physical Chemistry; Research Article; Selenium dioxide; Silver base alloys; Stainless steels; Sulfuric acid; Manganese electrodeposition; concentrations; Microstructure; SeO; Morphology; Electrocrystallization
• ISSN: 0021-891X; 1572-8838
• DOI: 10.1007/s10800-020-01489-y

Most studies of the electrodeposition of manganese have focused on finding the best operation conditions to obtain good recovery efficiencies. However, few studies have focused on how these variables affect the final deposition product, the formation of initial nuclei, and crystal growth. This work studies the effect of SeO 2 (0.14, 0.27, 0.54, and 0.81 mM) on the electrodeposition of manganese, the growth of the deposition product, and the microstructure of the crystals at different electrodeposition times. The catholyte was prepared by dissolving MnSO 4 ·H 2 O (0.27 M) at a pH of 3.7 and (NH 4 ) 2 SO 4 (0.9 M), and the anolyte was prepared with a solution of 0.5 M sulfuric acid. A stainless steel 316 plate was used as the cathode, and a Pb–Ag alloy plate was used as the anode (both with an area of 57 cm 2 ). The laboratory cell (500 mL) was partitioned with an anion-exchange membrane to prevent the transfer of ions between the compartments. Low electrodeposition efficiencies were found when using a SeO 2 concentration of less than 0.27 mM due to a high rate of hydrogen evolution and dissolution of the deposited manganese film, forming a blackish deposit (MnO 2 ). Above this concentration of SeO 2 , the deposits had a compact, well-defined crystalline structure and larger grain size. The availability of selenium during the initial stage of electrocrystallization allows for the formation of the first nuclei of manganese, promoting their growth. Graphic abstract