Organic Additive-Mediated Synthesis of Novel Cobalt(II) Hydroxides

Novel aspects of the physical chemistry of Co/SiO2 Fischer–Tropsch catalyst preparations

“…The Co 3 O 4 in Catalyst 10C must have originated from Co(OH) 2 present in Catalyst 10D before calcination, because precipitations of cobalt salts by alkali metal hydroxides are known to give cobalt hydroxides [9]. According to reference [10], Co(OH) 2 has no characteristic IR absorption for the Co-O bond. The presence of Co(OH) 2 in Catalyst 10D may not be surprising if we consider that only 0.55 equivalent silica per Co was used in the catalyst preparation.…”

Electrodeposition of α‐ and β‐cobalt hydroxide thin films via dilute nitrate solution reduction

“…Following the analogous nomenclature for nickel hydroxides, the α-Co(OH) 2 phase should indicate a complementary hydrated brucite phase having water molecules intercalated in the sheet structure (M(OH) 2-x (H 2 O) x ) x+ [10]. However, in the literature we have observed that reported α-Co(OH) 2 phases contained additional anionic compounds such as chloride, carbonate, or nitrate.…”

“…Those deposited at 95 °C yielded the brucite β-Co(OH) 2 . tures having a net positive charge between brucite-like layers and charge compensation balanced by anions such as nitrate, carbonate, or chloride in the interlayer space [10][11][12][13][14][15][16][17]. The net charge imbalance in α-Co(OH) 2 can be established by two mechanisms: hydroxyl deficiencies, or polyvalent cobalt ions in the layers [11,14,15].…”

“…Such an elevated concentration of a single salt suggested that the metal nitrate served as both the ion source for precipitation and the supporting electrolyte in solution. This process produces massive aggregates of poorly crystallized materials, often displaying turbostratic disorder between layers [10][11][12][13][14].…”

“…Nitrate precursors have been used for cobalt and nickel hydroxide electrodeposition for energy storage applications. In these experiments metal working electrodes such as steel, Pt, Co, and Ni were used, with metal nitrate salt concentrations >0.1 M [10][11][12][13][14]. Such an elevated concentration of a single salt suggested that the metal nitrate served as both the ion source for precipitation and the supporting electrolyte in solution.…”