Gas Diffusion Electrode for Oxygen Evolution Reaction Catalyst Testing

Abstract

The oxygen evolution reaction (OER) is one of the major contributors of efficiency loss in water electrolysis and consequently, development of OER catalysts to improve the electrolyser efficiency is a major reasearch theme in the field. Though the current commercial PEMWE may operate at anode potential <1.60 V, futue PEMWE may operate at potential higher than this as the drive to operate PEMWE at high current density is inceasing. Inorder to achieve this, an active and stable catalyst is required that can operate at this regime. Also, the potential experienced by the anode during the startup/shutdown of an electrolyser are different to the steady state value.Conventional OER testing involves catalysts coated on a conductive substrate submerged in an electrolyte solution, in a three electrode cell. However, such techniques are generally limited to low current densities due to oxygen bubble formation and site blocking at high current density limiting the system to study the OER kinetics below realistic operating current density. Although Rotating Disk Electrode(RDE) is widely employed to mitigate this, the RDE system is still not effective enough to remove the bubbles1.A floating electrode system developed by Kucernak et al2 shows that combining direct access with a lower catalyst loading improves the O2 gas mass transport and a higher current density could be achieved for the ORR. This technique also used for OER by Arenz et al.3, for easier bubble removal. Combining these two above mentioned systems, we have developed a new GDE cell system which allows screening of OER catalyst at industrially relevant current densities. This cell allows to study the OER kinetics at very realistic voltage/current regime and the information obtained helps to develop more active/stable catalyst.The OER catalyst diagnostics test from our GDE cell was comparable to the standard three electrode cell with an additional advantage of extended potential window upto 1.80 V vs.RHE. Preliminary results obtained from our study shows a promising opportunity to study the OER at high current densities.Reference FathiTovini, A.Hartig-Weiß, H.A.Gasteigerand, H.A.El Sayed, Journal of The ElectrochemicalSociety, 2021, 168, 014512.M.Zalitis,D.KramerandA.R.Kucernak,Phys.Chem.Chem.Phys.,2013,15,4329-4340Schröder,V.A.Mints,A.Bornet,E.Berner,M.FathiTovini,J.Quinson,etal., JACS Au 2021,1(3),247-25