• Mascaro, Lucia Helena
• Medina, Marina
• Santos, Hugo

Abstract

<jats:p>Amorphous molybdenum sulfide (MoS<jats:sub>x</jats:sub>) is a promising material for hydrogen evolution reaction (HER) due to its nearly zero hydrogen adsorption free energy at the sulfur (S) edge-sites. To prepare more efficient MoS<jats:sub>x</jats:sub>-based electrocatalysts, new attempts are required to increase the exposure of the MoS<jats:sub>x</jats:sub> lateral size and, therefore, increase the S atom’s contents. The majority of studies reported in the literature investigate MoS<jats:sub>x</jats:sub> over conductive substrates. However, MoS<jats:sub>x</jats:sub> can be electrodeposited over inexpensive and chemically stable platforms, such as semiconductors. This work presents the semiconductor substrate morphology effect for prepared sulfur-rich MoS<jats:sub>x</jats:sub> for electrochemical hydrogen evolution reaction. The electrodes are prepared by cyclic voltammetry with 25 cycles over TiO<jats:sub>2</jats:sub> film and TiO<jats:sub>2</jats:sub> nanotubes (TiO<jats:sub>2</jats:sub>NT) substrates. The MoS<jats:sub>x</jats:sub> deposit on TiO<jats:sub>2</jats:sub>NT presents an increase S atoms contents and exhibits excellent HER activity with a low overpotential of 93 ± 7.5 mV to reach −10 mA cm<jats:sup>−2</jats:sup> and a higher exchange current density equal to 91 <jats:italic>μ</jats:italic>A cm<jats:sup>−2</jats:sup>, and a smaller Tafel slope of 43 mV dec<jats:sup>−1</jats:sup>.</jats:p>

Topics

• density
• impedance spectroscopy
• molybdenum
• amorphous
• nanotube
• semiconductor
• Hydrogen
• current density
• cyclic voltammetry