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

Abstract

Recently, copper(II) complexes have been exten-sively 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 micros-copy, energy dispersive spectrometry, X-ray diffraction, Raman spectroscopy, in situ visible microscopy, in situ visible spectroelec-trochemistry, 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.