Oxygen evolution at ultrathin nanostructured Ni(OH)2 layers deposited on conducting glass

Ultrathin and transparent nanostructured Ni(OH)(2) films were deposited on conducting glass (F:SnO2) by a urea-based chemical bath deposition method. By controlling the deposition time, the amount of deposited Ni(OH)(2) was varied over 7 orders of magnitude. The turnover number for O-2 generation, defined as the number of O-2 molecules generated per catalytic site (Ni atom) and per second, increases drastically as the electrocatalyst amount decreases. The electrocatalytic activity of the studied samples (measured as the current density at a certain potential) increases with the amount of deposited Ni(OH)(2) until a saturation value is already obtained for a thin film of around 1 nm in thickness, composed of Ni(OH)(2) nanoplatelets lying flat on the conductive support. The deposition of additional amounts of catalyst generates a porous honeycomb structure that does not improve (only maintains) the electrocatalytic activity. The optimized ultrathin electrodes show a remarkable stability, which indicates that the preparation of highly transparent electrodes, efficient for oxygen evolution, with a minimum amount of nickel is possible. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.