Green Cobalt Oxide (CoOx) Film with Nanoribbon Structures Electrodeposited from the BF2-Annulated Cobaloxime Precursor for Efficient Water Oxidation

In this study, we report for the first time on the use of a water-soluble BF2-annulated cobaloxime, Co-(dmgBF(2))(2)(OH2)(2) (Co-DMB, dmgBF(2) = difluoroboryl-dimethylglyoxime), as a catalyst precursor for electrocatalytic water oxidation. Oxygen gas bubbles were clearly produced on the FTO electrode at a low overpotential under neutral pH conditions containing Co-DMB. Interestingly, stable green films were produced under these conditions. The current densities can reach to >5 mA/cm(2) at 1.1 V and >10 mA/cm(2) at 1.5 V (vs Ag/AgCl). The morphologies of the films showed nanoribbon structures, which were characterized by scanning electron microscope (SEM), energy-dispersive X-ray analysis (EDX), and X-ray photoelectron spectroscopy (XPS).