Optimizing Hybrid-Phase IrO2 Catalysts with Ti for Enhanced Oxygen Evolution Reaction for Proton Exchange Membrane Water Electrolysis

Yun, Young [Korea Institute of Energy Research]; Choi, Jungwoo [Korea Institute of Science & Technology]; Park, Youngtae [National Renewable Energy Lab., Golden, CO (United States)]; Park, Hyeongjung [Korea Institute of Energy Research]; Doo, Gisu [Korea Institute of Energy Research]; Kim, MinJoong [Korea Institute of Energy Research; Kyung Hee University]; Han, Sang [Korea Institute of Science & Technology]; Park, Jong [Yonsei University]; Lee, Sechan [Kookmin University; Korea Institute of Energy Research]; Lee, Changsoo [Korea Institute of Energy Research]; Cho, Hyun-Seok [Korea Institute of Energy Research; Sogang University]

doi:10.1002/smll.202503601

DOE OSTI · 2583644

Optimizing Hybrid-Phase IrO2 Catalysts with Ti for Enhanced Oxygen Evolution Reaction for Proton Exchange Membrane Water Electrolysis

View original source ↗Read source document ↗Export metadata ↓

Abstract

To realize a sustainable energy transition, water electrolysis-particularly proton exchange membrane water electrolysis (PEMWE)-holds significant promise. However, practical deployment is hindered by the cost and instability of the anode catalyst, IrO2. Recent studies indicate that tuning the Ir-O bond distance, via doping or composite formation, is key to enhancing the oxygen evolution reaction (OER) performance of IrO2-based electrocatalysts. Herein, a hybrid-phase Ti-incorporated IrO2 electrocatalyst is developed, exhibiting outstanding OER activity (298.8 mV at 100 mA cm-2) and stability over 25 h. This improvement originates from asymmetric interatomic interactions introduced by Ti, as revealed by combined experimental X-ray analyses and theoretical modeling. Ti incorporation induces tensile strain along the z-axis in IrO2 motifs, effectively reducing the average Ir-O bond distance and thereby enhancing OER activity. In situ X-ray absorption spectroscopy further confirms that at 1.5 V (vs. RHE), the elongated Ir-O bond facilitates -OOH* intermediate formation while suppressing Ir dissolution, contributing to superior stability. These findings underscore the critical role of Ir-O bond engineering in balancing activity and durability, offering strategic insights for the rational design of high-performance OER catalysts for renewable energy technologies.

Explore related subjects

08 HYDROGEN IrO2 OER stability dissolution mechanism in situ XAS oxygen evolution

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Yun, Young [Korea Institute of Energy Research], Choi, Jungwoo [Korea Institute of Science & Technology], Park, Youngtae [National Renewable Energy Lab., Golden, CO (United States)], Park, Hyeongjung [Korea Institute of Energy Research], Doo, Gisu [Korea Institute of Energy Research], Kim, MinJoong [Korea Institute of Energy Research; Kyung Hee University], Han, Sang [Korea Institute of Science & Technology], Park, Jong [Yonsei University], Lee, Sechan [Kookmin University; Korea Institute of Energy Research], Lee, Changsoo [Korea Institute of Energy Research], Cho, Hyun-Seok [Korea Institute of Energy Research; Sogang University]. 2025-07-02. Optimizing Hybrid-Phase IrO2 Catalysts with Ti for Enhanced Oxygen Evolution Reaction for Proton Exchange Membrane Water Electrolysis. https://doi.org/10.1002/smll.202503601

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related reports

DOE OSTI2026

Elucidating key reducing species beyond ions in hydrogen plasma smelting reduction of iron ore

Hydrogen plasma smelting reduction (HPSR) of iron ore has attracted significant attention over the past decade due to its high-temperature operation, rapid plasma mediated reduction kinetics, and simpler density-based separation of molten iron product, compared to H2-based solid-state reduction. All of these attributes enable processing of low-grade ores for downstream use in electric-arc furnaces, as virgin iron with low gangue content is required for high quality steel and improved furnace operation. While positive ions exist within the plasma arc, this work demonstrates that near the anodic ore surface, hydrogen radicals and vibrationally excited hydrogen species dominate and their densities correlate well with observed reduction rates. Species concentrations in the transferred plasma arc and at the plasma-ore interface are evaluated using coupled thermal plasma and near-wall non-equilibrium plasma models. The thermal plasma model is validated against experimental voltage data and spectroscopic measurements of plasma temperature and density for varying current inputs. Modeling of the near surface thermochemical non-equilibrium and micrometer scale anode sheath layer reveals, in addition to the expected H + , significant concentrations of ArH + and H$^+_3$ ions, typically not observed in thermal plasmas under thermodynamic equilibrium. Our results show that the inverted sheath structure at the anodic ore surface strongly suppresses reactive positive ion fluxes, while non-equilibrium electron-impact processes generate abundant hydrogen radicals and vibrationally excited species. These findings highlight the critical role of non-equilibrium effects in hydrogen arc-driven iron ore reduction and advance understanding beyond prevailing hypotheses centered on hydrogen ion-driven mechanisms.

08 HYDROGEN↗

DOE OSTI2026

SimH 2 : an integrated techno-economic modeling framework for hydrogen pipeline infrastructure and network optimization

Large-scale hydrogen (H 2 ) pipeline transport design and network optimization have seldom been reported due to the lack of a cost model accounting for the relationship between transport cost and hydrogen mass flow rate. Here, this work introduced a system-level cost model for hydrogen pipeline transport at supercritical state and integrated it with an existing CO 2 pipeline network tool, SimCCS, for hydrogen-specific pipeline design and optimization. The Intermountain West (I-West) region of the U.S., historically dependent on fossil fuel-based economies, is chosen to demonstrate the capabilities of our H 2 pipeline cost model and transport network optimization platform called SimH 2 . Two scenarios are examined: one where the pipeline is not allowed to pass through disadvantaged communities and the other where it is permitted. The results highlight that incorporating disadvantaged-community constraints lead to longer pipeline routes and increased transport costs, reflecting the trade-offs involved in equitable infrastructure development. It is demonstrated that the newly developed SimH 2 tool not only enables the efficient design of H 2 transportation pipelines but also optimizes the network by accounting for local terrain and the presence of disadvantaged areas.

08 HYDROGEN↗

DOE OSTI2026

Disordered hydrogen adsorption at the three-fold site of W(110)

Hydrogen often forms disordered phases on metals; however, deciphering the atomic-scale behavior requires experimental and modeling techniques that directly probe the short-range order between neighboring hydrogen adsorbates. Here, to address this challenge, we applied direct recoil spectroscopy (DRS) to investigate hydrogen adsorption on the W(110) surface. We show that the recoiled hydrogen flux measured during DRS is sensitive to the short range order of the adsorbed hydrogen. Ordered hydrogen neighbors are much more efficient at dechanneling incident ions along low-index surface channels, strongly suppressing the recoiled hydrogen flux along these directions. By modeling the DRS measurements with molecular dynamics for ordered and disordered hydrogen phases, we find that at a hydrogen surface coverage of approximately Θ = 0.6, the hydrogen adsorbates are bound to three-fold sites in a disordered phase at room temperature. This finding is consistent with transfer-matrix scaling model calculations that suggest the transition to an ordered hydrogen phase occurs at a greater surface coverage of Θ = 0.83.

08 HYDROGEN↗