Deposition of β-Co(OH)₂ Films by Electrochemical Reduction of Tris(ethylenediamine)cobalt(III) in Alkaline Solution

Abstract

Films of β-Co(OH)2 with a dense microcone morphology are electrodeposited at room temperature by reducing tris(ethylenediamine)cobalt(III) in alkaline solution. The synthesis exploits the fact that the kinetically inert Co(III) complex of ethylenediamine (en) is 35 orders of magnitude more stable than the kinetically labile Co(II) complex. [Co(en)3]3+ is therefore stable in alkaline solution, but [Co(en)3]2+ reacts with excess hydroxide ion to produce β-Co(OH)2. The electrodeposited β-Co(OH)2 is an active catalyst for the oxygen evolution reaction. Raman spectroscopy suggests that the surface of β-Co(OH)2 is converted to CoOOH at the potentials at which oxygen evolution occurs.

Structural evolution, magnetic properties and electrochemical response of MnCo2O4nanosheet films

“…3) and a weak band around 3600 cm À1 (Fig. The bands at 260 and 609 cm À1 match well with the E g modes reported for Co(OH) 2 (space group P 3m1) 25 whereas the band at 470 cm À1 can be assigned to A 1g mode, despite the shi in wavenumber when compared to Co(OH) 2 and Mn(OH) 2 (see Fig. The bands at 260 and 609 cm À1 match well with the E g modes reported for Co(OH) 2 (space group P 3m1) 25 whereas the band at 470 cm À1 can be assigned to A 1g mode, despite the shi in wavenumber when compared to Co(OH) 2 and Mn(OH) 2 (see Fig.…”

Observing the Electrochemical Oxidation of Co Metal at the Solid/Liquid Interface Using Ambient Pressure X-ray Photoelectron Spectroscopy

“…Previous electrochemical studies revealed that Co(OH) 2 is electrochemically oxidized to CoOOH in water-alkali electrolyzers in this voltage region. 2,28,29 Therefore, the formation of cobalt oxyhydroxide on the WE surface at +0.4 V holding potential is anticipated in our operando experiment. As shown in Figure 2a, there is an additional component which 19,21,24 We conclude that the new species formed at +0.4 V is CoOOH.…”

CoP nanosheet assembly grown on carbon cloth: A highly efficient electrocatalyst for hydrogen generation

“…However, the Co 2p 3/2 binding energy 781.9 eV observed in Figure 3a indicates that major oxidized species present in CoP/CC is Co(OH) 2 [57,58]. Despite of the presence of oxidized species such as Co(OH) 2 does not exhibit any appreciable HER current ( Figure S6).…”