Facile Synthesis of 3d Transition-Metal-Doped α-Co(OH)₂ Nanomaterials in Water–Methanol Mediated with Ammonia for Oxygen Evolution Reaction

Abstract

Layered cobalt hydroxides are cost-efficient electrocatalysts for oxygen evolution reaction (OER) in the field of energy conversion. Herein, we developed a facile synthesis method of 3d transition-metal-doped α-Co(OH)2 nanomaterials mediated with ammonia in water–methanol at room temperature. The doping of Cu2+ and Ni2+ leads to flower-like nanostructures similar to pure α-Co(OH)2, whereas the doping of Fe2+ produces nanoparticles with more than 2 times larger surface area in comparison with the Cu2+- and Ni2+-doped nanoflowers. The obtained dispersion with the addition of Nafion can be used directly as an electrocatalyst for OER with excellent catalytic activity, especially that the overpotential of Fe2+ doped is as low as 290 mV at 10 mA cm–2 and the turnover frequency is improved by 3 times as compared with that of α-Co(OH)2. Furthermore, the catalyst can be loaded onto foam nickel, which presents excellent durability with the current density unchanged under continuous chronoamperometry reaction for as long as 12 h and almost quantitative faradaic efficiency. The superior electrocatalytic properties combined with the simple synthesis without the tedious purification procedure is very promising for OER.

Electrochemical Reconstruction of Zn0.3Co2.7(PO4)2·4H2O for Enhanced Water Oxidation Performance

“…Meanwhile, several reports have also focused on the exploration of bimetallic systems, which delivered better catalytic activities compared to the monometallic systems. For example, Fe incorporation into the cobalt and nickel-based systems results in the significant reduction in the overpotentials. , In some reports, zinc doping into Co and Ni-based catalysts also resulted in the improvement of the catalytic performance. , Recently, development of α-M­(OH) 2 (M = Co, Ni) has gained significant attention as it delivers a better electrocatalytic ability compared to the corresponding β phase. , This improvement in the catalytic activity is attributed to the higher layer spacing in α-M­(OH) 2 that helps in the exposure of a larger number of metal ions to the electrolyte. Metal phosphates are another class of materials with promising electrocatalytic activities.…”

“…22,23 Recently, development of α-M(OH) 2 (M = Co, Ni) has gained significant attention as it delivers a better electrocatalytic ability compared to the corresponding β phase. 24,25 This improvement in the catalytic activity is attributed to the higher layer spacing in α-M(OH) 2 that helps in the exposure of a larger number of metal ions to the electrolyte. Metal phosphates are another class of materials with promising electrocatalytic activities.…”

Structural Buffer Engineering on Metal Oxide for Long‐Term Stable Seawater Splitting

“…And from its high‐resolution transmission electron microscopy (HRTEM) image, the ordered lattice fringes with interplanar spacing of 0.260 nm could be found, which is corresponding to α‐Co(OH) 2 (012) plane (Figure 1c). [ 24 ] In contrast, Co 2 (OH) 3 Cl shows a rectangular shape with uniform size of about 10 nm (Figure 1e), and exhibits the ordered (113) plane lattice fringes with the interplanar spacing of 0.285 nm (Figure 1f). [ 18 ] The EDS results show that Co, O, and Cl elements are distributed homogeneously along the scanning line, indicating the uniform distribution of Cl atoms on Co 2 (OH) 3 Cl nanoplatelet (Figure S1, Supporting Information).…”

Enhancing the oxygen evolution reaction of cobalt hydroxide by fabricating nanocomposites with fluorine-doped graphene oxide

“…19 In recent years, cobalt hydroxide (Co(OH) 2 )-based catalysts have received increased attention owing to their environmental friendliness and Earth abundance. [20][21][22][23][24] However, pure Co(OH) 2 shows low OER activity since the fully occupied t 2g orbitals of the metal centre contribute to low electron transfer conductivity. 25 But incorporating heteroatoms or other metal ions into the Co(OH) 2 matrix improves the electronic properties and shows strong OER activity.…”