Hierarchical Cu(OH)2@Co(OH)2Nanotrees for Water Oxidation Electrolysis

In order to achieve highly-efficient water electrolysis, an effective strategy is to design three-dimensional hierarchical nanostructures by decorating the surface of the main catalysts with co-catalytic metal compounds. Herein, leave-like ultrathin Co(OH)(2)nanoflakes are grown on branch-like Cu(OH)(2)nanowires via the combination of an anodization process together with an electrodeposition process. The resulting hierarchical Cu(OH)(2)@Co(OH)(2)nanotrees can be used as efficient OER electrocatalysts with an overpotential as low as 283 mV to reach 10 mA cm(-2). After 20 hours of multi-current density stability test, the electrode shows negligible degradation while retaining an overpotential of 290 mV to reach 10 mA cm(-2), thus showing a high electrocatalytic capability and stability. This work provides a new strategy to improve transition metal electrocatalysts in view of low-cost water oxidation in alkaline media.