Application: Oxygen Evolution Reaction (OER).
Instrument: HPR-40 DEMS.
Cell: ECL-Static.
Configuration: Catalyst-coated working electrode with continuous operando oxygen analysis.
Key Capabilities: Quantitative O₂ analysis, calibration, Faradaic efficiency, real-time DEMS, operando catalyst evaluation.
Why read this paper?
Improving the efficiency of the oxygen evolution reaction is critical for the development of practical water electrolysers, but understanding whether increased current corresponds to genuine oxygen production requires accurate, quantitative gas analysis. In this study, the Hiden HPR-40 DEMS fitted with the ECL-Static electrochemical cell was used to continuously monitor oxygen evolution while evaluating tungstate-modified nickel-iron oxyhydroxide catalysts under alkaline conditions. The catalyst was mounted directly onto the working electrode, allowing oxygen production to be measured in real time throughout the electrochemical experiments.
Following calibration of the DEMS response, the HPR-40 provided quantitative oxygen evolution measurements used to determine Faradaic efficiency across the applied potential range. By directly correlating measured oxygen production with electrochemical current, the authors confirmed that the enhanced catalytic activity corresponded to genuine oxygen evolution at close to 100% Faradaic efficiency, ruling out parasitic side reactions such as H₂O₂ production. In a second, mechanistically critical application, the HPR-40 was used to perform ¹⁸O isotope labelling experiments using ¹⁸O-labelled KOH electrolyte. By monitoring the ³²O₂, ³⁴O₂ and ³⁶O₂ isotopologue distribution, the authors demonstrated that oxygen is released from the nickel active site rather than directly from the tungsten-peroxo species — providing direct evidence for a previously unrecognised electrophilic metal-peroxo reaction pathway.
This paper demonstrates how the HPR-40 DEMS combines quantitative gas analysis, Faradaic efficiency measurements and operando electrochemistry to provide direct evidence of catalyst performance, making it an outstanding reference for researchers developing next-generation OER catalysts.
Paper Reference: Lee, H.S., Shin, H., Park, S., Kim, J., Jung, E., Hwang, W., Lee, B.-H., Yoo, J.M., Antink, W.H., Lee, K., Lee, S., Na, G., Suh, K., Kim, Y.S., Lee, K.-S., Yoo, S.J., Sung, Y.-E. and Hyeon, T. (2023). Electrochemically generated electrophilic peroxo species accelerates alkaline oxygen evolution reaction. Joule, 7(8), pp.1902–1919.
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