Controlled Surface-Assembly of Nanoscale Leaf-Type Cu-Oxide Electrocatalyst for High Activity Water Oxidation

The controlled surface deposition of a robust and high-performance nanostructured copper-oxide (CuOx-NLs) electrocatalyst for water oxidation is presented. The material exhibits a characteristic leaf-type morphology and self-assembles on a copper substrate by straightforward constant-current anodization. The oxygen onset occurs at about 1.55 V versus RHE (eta = 320 mV), which is 400-500 mV less than for amorphous Cu-oxide films. A Tafel slope of 44 mV dec(-1) is obtained, which is the lowest observed relative to other copper-based materials. Long-term catalytic performance and stability tests of the electrocatalytic CuOx-NLs sample show a stable current density of >17 mA cm(-2) for oxygen evolution, which was sustained for many hours.