Elucidating the Mechanism of Oxygen Evolution Reaction on Nanostructured Copper-Based Catalysts

In water splitting processes, the oxygen evolution reaction (OER) is one of the main kinetic control steps that should be triggered by high-efficiency catalysts. A series of Cu-based catalysts are considered potential candidates. This work provides a simple and effective strategy for fabricating large-scale copper-based catalysts by anodization on a copper foil at room temperature in a KOH solution. The representative petal-shaped CuO and Cu(OH) 2 nanorods are obtained. The corresponding surface areas are 0.0197 and 1.966 m 2 /g, respectively. The surface wettability of Cu(OH) 2 is lower than that of CuO. The catalytic performance is studied by linear sweep voltammetry (LSV). The results show that the potential of the OER for CuO at 10 mA/cm 2 is 1.67 V, which reduces by 130 mV compared to Cu(OH) 2 . The CuO could keep 10 mA/cm 2 after a 1 h chronoamperometry test, which is about 3 times higher than that of Cu(OH) 2 . To verify the distinguishing catalytic difference between CuO and Cu(OH) 2, in situ Raman spectra have been recorded. Inspiringly, the Cu III active specie at 603 cm –1 is captured during the OER process on CuO instead of Cu(OH) 2 . The related mechanism has been discussed in detail.