Water Oxidation by a Copper(II) Complex with 6,6′-Dihydroxy-2,2′-Bipyridine Ligand: Challenges and an Alternative Mechanism

Recently,
copper(II) complexes have been extensively investigated
as oxygen-evolution reaction (OER) catalysts through a water-oxidation
reaction. Herein, new findings regarding OER in the presence of a
Cu(II) complex with 6,6′-dihydroxy-2,2′-bipyridine ligand
are reported. Using scanning electron microscopy, energy dispersive
spectrometry, X-ray diffraction, Raman spectroscopy, in situ visible
microscopy, in situ visible spectroelectrochemistry, X-ray absorption
spectroscopy, and electrochemistry, it is hypothesized that the film
formed on the electrode’s surface in the presence of this complex
causes an appropriated matrix to produce Cu (hydr)oxide. The resulting
Cu (hydr)oxide could be a candidate for OER catalysis. The formed
film could form Cu (hydr)oxide and stabilize it. Thus, OER activity
increases in the presence of this complex.