Fabrication of Mo-modified carbon felt as candidate substrate for electrolysis: Optimization of pH, current and metal amount

Abstract

Mo was electrochemically deposited over a carbon felt (C) support in order to enhance hydrogen evolution activity of the support and make it a candidate for further modifications. For this aim, the effects of pH of deposition bath solution, deposition current and amount of deposited Mo were studied and optimized. Hydrogen evolution activity of the electrodes was evaluated in 1 M KOH solution with the help of electrochemical techniques. Surface structures of the electrodes were examined by scanning electron microscopy (SEM). It was found that 1 g Mo/g C modified electrode at pH 6 and 50 mA current exhibits the best hydrogen releasing performance. The enhanced current density at this electrode under −1.60 V(Ag/AgCl) was 59.6% with respect to the bare support, which demonstrates that modifying the support by a thin Mo layer favors the hydrogen evolution reaction (HER) and reduces the energy requirement. The high hydrogen evolution performance of this modified substrate was assigned to its excellent structure, large surface area as well as high intrinsic catalytic activity of Mo. According to experimental findings, the Mo-modified C substrate was suggested for preparation of further modified electrode materials, especially with trace amounts of precious metals. © 2018 Hydrogen Energy Publications LLC