Abstract
Hydrogen production by proton exchange membrane (PEM) water electrolysis is among the promising energy storage solutions to buffer an increasingly volatile power grid employing significant amounts of renewable energies. In PEM electrolysis research, 24 h galvanostatic measurements are the most common initial stability screenings and up to 5,000 h are used to assess extended stability, while commercial stack runtimes are within the 20,000–50,000 h range. In order to obtain stability data representative of commercial lifetimes with significantly reduced test duration an accelerated degradation test (ADT) was suggested by our group earlier. Here, we present a study on the broad applicability of the suggested ADT in RDE and CCM measurements and showcase the advantage of transient over static operation for enhanced catalyst degradation studies. The suggested ADT-1.6 V protocol allows unprecedented, reproducible and quick assessment of anode catalyst long-term stability, which will strongly enhance degradation research and reliability. Furthermore, this protocol allows to bridge the gap between more fundamental RDE and commercially relevant CCM studies.
Highlights
The development of general test protocols for the Oxygen Evolution Reaction (OER) and, in particular, for degradation screening of OER catalysts is of crucial importance for the success of water electrolysis and other industrial electrochemical processes that make use of the OER
A strong electrode potential dependence of catalyst dissolution was observed, which could be significantly enhanced by applying transient accelerated degradation test (ADT) protocols instead of static CA or CP protocols in, both, RDE and catalyst coated membranes (CCMs) tests
Additional physical catalyst damage was observed on IrOx-ADT samples subjected to potentials ⩾ 1.8 VRHE while physicochemical catalyst properties of IrOx-ADT-1.6 V developed analogous to static tests
Summary
The development of general test protocols for the Oxygen Evolution Reaction (OER) and, in particular, for degradation screening of OER catalysts is of crucial importance for the success of water electrolysis and other industrial electrochemical processes that make use of the OER. 0.95 VRHE represents the transition of IrIII+ to IrIV+.14 With increasing Eup a larger amount of redox active Ir and stabilization of reduced Ir states (cf growing redox feature b, Fig. 1a) was observed for the ADTs. Strikingly, transient operation in ADT-1.4 V already resulted in stronger change than the most severe static protocol CA-2.0 V (Fig. 1b).
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