In operando activation of alkaline electrolyzer by ruthenium spontaneous deposition

Abstract

Conventional alkaline electrolyzers used for water splitting can considerably increase their efficiency upon modification of the surface of the electrode. Here we present in operando evidence of activation of a conventional alkaline electrolyzer using nickel electrodes modified by spontaneous deposition of ruthenium (1 × 10−5 M in 30% w/v KOH electrolyte). Surface modifications were analyzed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. Conventional electrochemical techniques were used to establish the kinetic and thermodynamic parameters of hydrogen generation before and after the spontaneous deposition of Ru. Changes on the nickel electrodes by direct modification of the electrolyte allowed to reduce the potential at minimum current from 1.64 to 1.00 V under the same operating conditions. That is, a considerable increase in the electrolysis efficiency was attained by reducing the activation overvoltage. Thus, using a simple, inexpensive, and reproducible method, it is possible to increase the efficiency of conventional electrolyzers.