Electrochemical characterization of the Ni–W catalyst formed in situ during alkaline electrolytic hydrogen production—Part II
Objective of this work was to investigate the electrocatalytic efficiency using quasi-potentiostatic, galvanostatic and impedance spectroscopy techniques of the Ni–W catalysts obtained by in situ electrodeposition in an alkaline, 6 M KOH, electrolyser. Synergetic effect is observed, with its maximum at industrial conditions (high temperature and current density). The Tafel slopes are ∼120 mV and exchange current densities are in the range of 10−4 mA cm−2. Results are presented to show the Tafel slopes, the exchange current densities, the apparent energy of activation and the apparent electrochemical surface of the in situ formed Ni–W catalyst. Obtained results could have significant impact on the industrial process for the alkaline hydrogen production and suggest to good catalytic performance not only from the increase of the real surface area of the electrodes, but also from the true catalytic effect.
Graphical abstract.Figure optionsDownload full-size imageDownload high-quality image (92 K)Download as PowerPoint slideHighlights► Investigation on the electrocatalytic efficiency of Ni–W catalyst for the HER. ► Synergetic effect is observed, with its maximum when applying industrial conditions. ► Ni–W catalyst reveal the Tafel slopes ∼120 mV, j0 ∼ 10−4 A cm−2. ► The apparent energy of activation of 30 kJ mol−1.
Journal: Applied Catalysis A: General - Volume 405, Issues 1–2, 3 October 2011, Pages 29–35