Ab Initio Thermodynamics Insight into the Structural Evolution of Working IrO2 
Catalysts in Proton-Exchange Membrane Electrolyzers

Opalka, Daniel; Scheurer, Christoph; Reuter, Karsten

doi:10.1021/acscatal.9b00796

Item

ITEM ACTIONSEXPORT

Add to Basket

Local TagsRelease HistoryDetailsSummary

Released

Journal Article

Ab Initio Thermodynamics Insight into the Structural Evolution of Working IrO₂ Catalysts in Proton-Exchange Membrane Electrolyzers

MPS-Authors

There are no MPG-Authors in the publication available

External Resource

No external resources are shared

Fulltext (restricted access)

There are currently no full texts shared for your IP range.

Fulltext (public)

There are no public fulltexts stored in PuRe

Supplementary Material (public)

There is no public supplementary material available

Citation

Opalka, D., Scheurer, C., & Reuter, K. (2019). Ab Initio Thermodynamics Insight into the Structural Evolution of Working IrO₂ Catalysts in Proton-Exchange Membrane Electrolyzers. ACS Catalysis, 9(6), 4944-4950. doi:10.1021/acscatal.9b00796.

Cite as: https://hdl.handle.net/21.11116/0000-000A-77E8-B

Abstract

At the cell voltages required to reach technologically viable current densities in proton-exchange membrane (PEM) electrolyzers, IrO₂ catalysts are suspected to undergo a transformation to an amorphous hydrous form. Here, we present a systematic ab initio thermodynamics study analyzing the shape and stability of IrO₂ nanoparticles in this potential range. Our results confirm a thermodynamic instability of the rutile crystal structure induced by the stabilization of highly oxidized O species at the surface already at onset potentials for the oxygen evolution reaction (OER). Intriguingly, this is preceded by a transformation of the equilibrium shape at even lower potentials. Instead of the well-studied IrO₂(110) facets, this shape is dominated by IrO₂(111) facets that have hitherto barely received attention. Our findings highlight the need to extend detailed characterization studies to this high-potential range, not the least to establish more suitable active-site models for the OER that may then serve as the basis for computational screening studies aimed at reducing the rare-metal content in future PEM OER catalysts.