Electrodeposition of epitaxial Co(OH)₂ on gold and conversion to epitaxial CoOOH and Co₃O₄

Abstract

Abstract

Operando Surface X-ray Diffraction Studies of Structurally Defined Co3O4 and CoOOH Thin Films during Oxygen Evolution

“…2 3 4 These materials are earth abundant, easy to prepare, and present good catalytic properties and stability in alkaline and neutral electrolytes. 2,5,6,7 Cobalt oxides may be prepared with an amorphous or a crystalline structure, using a variety of methods, including thermal salt decomposition, 8 autoclave synthesis, 9 photochemical reactions, 10 sol-gel synthesis, 11 Co electrodeposition and subsequent oxidation, 12,13,14 and direct oxide electrodeposition. 2,15,16 For understanding and further developing Co oxide catalysts it is necessary to clearly separate intrinsic structure-property relationships, which describe the dependence of the OER activity on the atomic-scale surface structure, from effects caused by the nano-and microscale material morphology.…”

Particle size-controlled synthesis of high-performance MnCo-based materials for alkaline OER at fluctuating potentials

“…The electrodeposition of Co 3 O 4 spinel on a gold surface enabled the control of the oxidation state of Co and ensured a high surface area and active metal dispersion. 17,18 A high OER performance was achieved for spinel type materials and could be optimised by the enhancement of the surface area via nanostructuring, like hard-templating. This led to a low η of 0.34 V at 10 mA cm −2 .…”

Cobalt oxysulphide/hydroxide nanosheets with dual properties based on electrochromism and a charge storage mechanism

“…Generally, the as-prepared a-Co(OH) 2 lm can be obtained by the electrodeposition technique. 15 The Co(OH) 2 is a hydrotalcite-like structure with the hexagonal crystal phase of space group P3m1 with lattice parameters of a ¼ b ¼ 0.3183 nm, and c ¼ 0.4652 nm. 15,16 From the XRD pattern, Co(OH) 2 is the main composition in the mixed materials.…”

“…15 The Co(OH) 2 is a hydrotalcite-like structure with the hexagonal crystal phase of space group P3m1 with lattice parameters of a ¼ b ¼ 0.3183 nm, and c ¼ 0.4652 nm. 15,16 From the XRD pattern, Co(OH) 2 is the main composition in the mixed materials. Note that the peak at 9.8 refers to the (001) plane of a-phase Co(OH) 2 relating to anions (NO 3 À , S 2À and SO x 2À ) intercalated within the interlayer of nanosheets (JCPDS no.051-1731).…”

“…14,16,20 The CoO(OH) is a hexagonal crystal phase of space group R3m with lattice parameters of a ¼ b ¼ 0.3183 nm, and c ¼ 1.315 nm. 15,16 The caxis of CoO(OH) clearly expands and disorders when compared with the crystal structure of Co(OH) 2 . Meanwhile, CoS is a hexagonal crystal phase of space group P6 3 /mmc with lattice parameters of a ¼ b ¼ 0.3368 nm, and c ¼ 0.517 nm.…”