Mechanistic Analysis of Hydrogen Evolution Reaction on Pt in HClO₄ Using Inverted Rotating Disc Electrode

Abstract

An inverted rotating disc electrode (IRDE) setup was fabricated to study the hydrogen evolution reaction (HER) on a Pt electrode. Potentiodynamic polarization studies were conducted in solutions from 5 to 100 mM HClO4 on Pt at three different rotational speeds. Periodic anodic activation of the electrode yielded repeatable results. At high currents, bubble formation adversely affects current measurement in the rotating disc electrode, but not in IRDE. At large cathodic overpotentials, HER current in IRDE is limited by the mass transfer of H+ ions. Simulations show that the polarization results of HER on Pt IRDE are described well by the Volmer Heyrovsky mechanism.

Research on engineered electrocatalysts for efficient water splitting: a comprehensive review

“…The linearity reveals that H 2 evolution follows first order reaction and a noticeable change in j k is observed. 23 The fresh catalysts show an increase in the electron transfer rate with increasing overpotential, whereas in the catalysts after chronoamperometry, the observed constant j k values (with overpotential), implying a rapid electron transfer. The obtained Levich slope ( B ) and transferred electrons number ( n ) ( n < 1) (0.72 < n < 0.94) suggest that the Volmer reaction become the rate-limiting step.…”

“…Yan et al reported that HER could be diffusion limited when the electrode kinetics becomes fast, as evidenced by the rotation speed dependent HER current on Pt in acid and the overlap of HER polarization curve with concentration overpotential curve. 23 The diffusion limitation of HER originated from the slow mass transport of produced H 2 on the electrode to the bulk electrolyte and the reversible nature of HOR/HER. Though the diffusion overpotential for HER becomes small, it has a significant impact on kinetic analysis in the low overpotential region, leading to inaccurate mechanistic interpretations.…”

“…Franceschini et al reported that Ni/Ru electrodes, after being characterized for different electrochemical techniques (LSV by RDE at different temperatures, EIS at different potentials), were subjected to a chronoamperometric pulse for 4 h to analyze the short-term ageing effect of the catalysts during the hydrogen evolution. 23 Kouteckye–Levich analysis shows that there are changes in the number of electrons transferred, which increased after short term ageing and the Volmer reaction become the rate determining step except for the NR3600 catalyst, which seems to exhibit a change in the reaction mechanism after ageing. The results of Tafel and EIS analysis indicates Langmuir type H adsorption isotherm not only in freshly synthesized catalysts but also in aged catalysts, unlike that observed in pure nickel, where ageing induces a Temkin type H adsorption.…”

“…The investigation of HER on Pt were carried out by Bockris et al 24 up to a current density of 100 mA cm −2 , Strumcnik et al 24 up to a current density of 125 mA cm −2 , Kucernak et al 24 up to a current density of 125 mA cm −2 , and Koster et al 24 up to a current density of 60 mA cm −2 . An inverted RDE (IRDE) can be used to overcome this limitation: 23 mass transfer characteristics of IRDE are similar to those of RDE. In IRDE, the electrode surface is oriented upward, and the gaseous products form microbubbles released shortly from the electrode surface and move up due to buoyant forces.…”

“…IRDE has been used to study Ni–Mo alloys, Zn electrodeposition, CO 2 reduction, pulse plating of Cu–Co, and Co electrodeposition. 23 Studies on the fluctuation of concentration overpotential during HER on Pt IRDE in alkaline solution have been reported, and the hydrodynamics of two-phase flow and size distribution of microbubbles during HER on Pt IRDE in acidic solution have been reported. 23 Since an electrode becomes oriented in the downward direction in a hanging meniscus configuration, it encountered the same difficulty in disengaging gas bubbles as normal RDE.…”