Effect of Experimental Operations on the Limiting Current Density of Oxygen Reduction Reaction Evaluated by Rotating‐Disk Electrode

Abstract

The universal linear scan voltammogram measurement on the rotating disk electrode (RDE) has been identified as a simple method to investigate the oxygen reduction activity of electrocatalysts. The steady‐state limiting current density Ilim indicates the maximum diffusion current density in the oxygen reduction reaction (ORR) during RDE measurement, which should be a fixed value in theory for a 4e ORR in a particular concentration solution and at a certain rotate speed. However, in experiments, Ilim is always variable and smaller than theoretical value even though with the same the catalyst, electrode, and rotator. So the impact of various experimental operating parameters on Ilim is highly necessary to be investigated. In this paper, factors, such as catalyst loading, O2 inlet condition, O2 flow rate, gas tightness, solution concentration, and purity, have been investigated for their effects on the Ilim of ORR on three typical catalysts (20 % commercial Pt/C, Iron/Nitrogen/Carbon‐catalyst and N‐doped carbon nanotubes). The results indicate that the catalyst loading and O2 inlet condition are the key factors influencing the Ilim of ORR. While, the O2 flow rate, gas tightness, solution concentration, and purity have little influence on the Ilim of ORR. The correct Ilim could be obtained under the optimized catalyst loading and the O2 inlet with an extended sand core tube.

A Facile Way for Acquisition of a Nanoporous Pt–C Catalyst for Oxygen Reduction Reaction

“…It is also important to mention that the limiting current density values for both Pt–C and Pt catalysts are close to the theoretical value, indicating 4e − reduction mechanism. [ 57 ] The mass and specific activities of Pt–C catalyst calculated from the corresponding LSV curve at 0.9 V RHE are about 0.02 A mg −1 Pt and 0.06 mA cm −2 Pt , respectively. These values are comparable with one measured at identical conditions for commercial Pt/C catalyst [ 58–61 ] (note that electrocatalytic activity of platinum is significantly lower in 0.5 m H 2 SO 4 acid electrolyte than in 0.1 m HClO 4 ).…”

Green synthesis of iron and nitrogen co‐doped porous carbon via pyrolysing lotus root as a high‐performance electrocatalyst for oxygen reduction reaction

“…0592 × pH. Catalyst suspension was prepared based on previous work 40 . The glassy carbon disk electrode was covered with 20 μL suspensions and dried at ~25°C for 1 hour.…”

Can Aqueous Zinc–Air Batteries Work at Sub‐Zero Temperatures?

“…Additionally, the ORR limiting current density and the ORR electron transfer number are unaffected under lower temperatures (Figure S4), manifesting little effect on oxygen mass transfer or the selective 4 e À reduction pathway. [28] (3) Anodic reaction. Zn-Zn symmetry cells were evaluated to determine the influence of anodic kinetics.…”