Urchin-Like Cobalt-Copper (Hydr)oxides as an Efficient Water Oxidation Electrocatalyst

Graphical Looks like a sea urchin : Cobalt-Copper (hydr)oxides with urchin-like nanostructure were successfully prepared. They have a high electrocatalytic activity and a relatively robust structure towards oxygen evolution reaction under alkaline conditions. The suitable Cu 2+ dopant and the anion exchange process promote the formation of high-valent active Co species. This leads to the reconstruction of the catalyst morphology and structure with a larger surface area, which is beneficial for the electrocatalytic water splitting. The development of efficient and low-cost oxygen evolution reaction (OER) catalysts is essential for the generation of clean hydrogen energy from water splitting. Herein, a novel hierarchical urchin-like cobalt-copper (hydr)oxide in situ grown on copper foam (CoCuO x H y (S)/CF) was synthesized through the electrochemical transformation of cobalt-copper sulfides (Co 9 S 8 -Cu 1.81 S) via anodization process. This CoCuO x H y (S)/CF anode exhibited a low overpotential ( η ) of 274 mV at a current density of 100 mA cm −2 with a robust durability over a period of 40 h when operated at 10 mA cm −2 . Further investigations imply that the unique nanowires aggregated urchin-like structure of CoCuO x H y (S) derived from the in situ anion exchange process could facilitate the exposure of active sites and accelerate electron transfer. More importantly, the incorporation of copper resulted in an electronic delocalization around the cobalt species, which contributed to reach a high-valent catalytically active cobalt species and further improved the OER performance.