EQCM study of the electrodeposition of manganese in the presence of ammonium thiocyanate in chloride-based acidic solutions

Effect of gluconate ions on electroreduction phenomena during manganese deposition on glassy carbon in acidic chloride and sulfate solutions

“…The latter shows the presence of two phases in the deposit oxidizing at various potentials. This is usually attributed to the dissolution of pure metal (peaks A and A1) as well as MnO or Mn(OH) 2 precipitated in the manganese phase during intensive hydrogen evolution [5,23]. Similar phenomenon was observed also in the current study, since quite large amount of white precipitate was formed during washing (in an alcohol or acetone) of the deposit obtained from the chloride-gluconate bath.…”

“…Some inorganic additives are intentionally introduced to the solutions to increase current efficiency of manganese deposition. SO 3 2À , SeO 3 2À TeO 3 2À or SCN À ions are reduced on the cathode producing adsorbates acting as a poison for hydrogen evolution [1,[4][5][6][7][8]. Alternative organic additives (amines, paraformaldehyde, glycerol) [7] or non-aqueous solutions [9,10] as well as various electrolysis performances (pre-electrolysis, membrane reactor) [11,12] were also tested for the improvement of the process.…”

Electrodeposition of Alloys Coatings from Electrolytic Baths Prepared by Recovery of Exhausted Batteries for Corrosion Protection

“…This XDR measurement also indicated that these experimental conditions did not favor the formation of a Zn-Mn alloy. This result may be related to the formation of Mn(OH) 2 (s) species on the substrate surface due to the hydrogen formation under these experimental conditions, resulting in an increase in the pH in the vicinity of the working electrode [38]. In addition, the formation of Mn(OH) 2 in high alkaline conditions agrees well with the Eh x pH (Pourbaix) diagrams [39].…”

Electrodeposition of High-Mn Zinc-Manganese Alloys From Chloride Eectrolyte

“…The appropriate explanation for such an increase in current efficiency with the sweep rate could be the fact that Mn is the most electronegative metal that can be electrodeposited from aqueous solutions, so it is unstable and tends to dissolve easily in acidic media, during the inverse scan [11]. This is non-faradaic dissolution (mass loss without charge transfer associated) so it does not have an associated oxidation current in the voltammogram [12]. The higher sweep rate reduces the time available for Mn self-dissolution and consequently increases the amount of Mn which contributes to the A 2 peak current, i.e.…”

“…6 d, g) posses pores with diameter of 1 -2 µm, probably due to hydrogen evolution during alloy deposition. However, iron, the substrate material, is not detected by EDS analysis on any sample, which proves that the pores are present only on the coating surface, and do not extend into the coating depth [12].…”