Abstract
The Langmuir adsorption isotherms of over-potentially deposited hydrogen (OPD H) for the cathodic hydrogen evolution reaction (HER) at poly-Au and Rh/0.5 M aqueous electrolyte interfaces have been studied using cyclic voltammetric and ac impedance techniques. The behavior of the phase shift for the optimum intermediate frequency can be linearly related to that of the fractional surface coverage of OPD H for the cathodic HER at the interfaces. The phase-shift profile (−ϕ vs. E) for the optimum intermediate frequency, i.e., the phase-shift method, can be used as a new electrochemical method to determine the Langmuir adsorption isotherm (θ vs. E) of the OPD H for the cathodic HER at the interfaces. At the poly-Au/0.5 M aqueous electrolyte interface, the equilibrium constant (K) and the standard free energy of the OPD H are and 32.2 kJ/mol, respectively. At the poly-Rh/0.5 M aqueous electrolyte interface, K and of the OPD H are or and 19.3 or 11.0 kJ/mol depending on E, respectively. In contrast to the poly-Au electrode interface, two different Langmuir adsorption isotherms of OPD H are observed at the poly-Rh electrode interface. The two different Langmuir adsorption isotherms of OPD H correspond to two different adsorption sites of OPD H on the poly-Rh electrode surface. © 2003 The Electrochemical Society. All rights reserved.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
