Design of Nickel Electrodes by Electrodeposition: Effect of Internal Stress on Hydrogen Evolution Reaction in Alkaline Solutions

Here we report the fabrication of Ni electrodes with induced internal stress, electrodeposited in the presence of coumarin (COU) or 1,3,6-naphthalenetrisulfonic acid trisodium salt (NTS), to enhance the hydrogen evolution reaction. The crystallographic structure and morphology of the Ni electrodeposits prepared from a plating bath containing COU showed large columnar structures with a [100] preferred orientation, whereas the electrodeposits with NTS grew fine columnar structures along the [111] and [100] direction. The tensile or compressive stress in the Ni lattice was controlled by additive concentration, which led to the incorporation of hydrogen or sulfur in the Ni matrix. The Ni electrode with induced compressive stress exhibited a higher exchange current density and lower Tafel slopes than those with induced tensile stress, which can be attributed to modification of the hydrogen adsorption energy, as evidenced by a downshift in the d-band center. (C) 2017 Elsevier Ltd. All rights reserved.