Self-Supported Cu-Based Nanowire Arrays as Noble-Metal-Free Electrocatalysts for Oxygen Evolution

Crystalline Cu-based nanowire arrays (NWAs) including Cu(OH)(2), CuO, Cu2O, and CuOx are facilely grown on Cu foil and are found to act as highly efficient, low-cost, and robust electrocatalysts for the oxygen evolution reaction (OER). Impressively, this noble-metal-free 3D Cu(OH)(2)-NWAs/Cu foil electrode shows the highest catalytic activity with a Tafel slope of 86mVdec(-1), an overpotential () of about 530mV at approximate to 10mAcm(-2) (controlled-potential electrolysis method without iR correction) and almost 100% Faradic efficiency, paralleling the performance of the state-of-the-art RuO2 OER catalyst in 0.1m NaOH solution (pH12.8). To the best of our knowledge, this work represents one of the best results ever reported on Cu-based OER systems.