Enhanced Stability and Thickness‐Independent Oxygen Evolution Electrocatalysis of Heterostructured Anodes with Buried Epitaxial Bilayers

Baniecki, J. D.; Yamaguchi, H.; Harnagea, Cătălin; Ricinschi, Dan; Gu, Zhiqi; Spanier, Jonathan E.; Yamazaki, Takashi; Aso, Hiroyuki

doi:10.1002/aenm.201803846

Cited by 18 publications

(14 citation statements)

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“…Through atomic-level control of synthesis in form of epitaxial thin films and heterostructures it is now possible to create desired combinations of different chemical compositions for perovskite oxides ( Gunkel et al, 2017 ; Baniecki et al, 2019 ). This allows engineering surface cover layers ( Akbashev et al, 2018 ; Heymann et al, 2022 ), and controlling chemical gradients and electronic properties independently via charge-transfer processes ( Gunkel et al, 2020b ; Burton et al, 2022 ) or sub-surface engineering ( Akbashev et al, 2018 ; Zhang et al, 2020 ), and enables a systematic understanding and tuning of activity and degradation from atomically defined model systems ( Weber and Gunkel, 2019 ).…”

Section: Atomistic Understanding Of Activity and Degradation Relies O...mentioning

confidence: 99%

Activity-Stability Relationships in Oxide Electrocatalysts for Water Electrolysis

et al. 2022

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The oxygen evolution reaction (OER) is one of the key kinetically limiting half reactions in electrochemical energy conversion. Model epitaxial catalysts have emerged as a platform to identify structure-function-relationships at the atomic level, a prerequisite to establish advanced catalyst design rules. Previous work identified an inverse relationship between activity and the stability of noble metal and oxide OER catalysts in both acidic and alkaline environments: The most active catalysts for the anodic OER are chemically unstable under reaction conditions leading to fast catalyst dissolution or amorphization, while the most stable catalysts lack sufficient activity. In this perspective, we discuss the role that epitaxial catalysts play in identifying this activity-stability-dilemma and introduce examples of how they can help overcome it. After a brief review of previously observed activity-stability-relationships, we will investigate the dependence of both activity and stability as a function of crystal facet. Our experiments reveal that the inverse relationship is not universal and does not hold for all perovskite oxides in the same manner. In fact, we find that facet-controlled epitaxial La0.6Sr0.4CoO3-δ catalysts follow the inverse relationship, while for LaNiO3-δ, the (111) facet is both the most active and the most stable. In addition, we show that both activity and stability can be enhanced simultaneously by moving from La-rich to Ni-rich termination layers. These examples show that the previously observed inverse activity-stability-relationship can be overcome for select materials and through careful control of the atomic arrangement at the solid-liquid interface. This realization re-opens the search for active and stable catalysts for water electrolysis that are made from earth-abundant elements. At the same time, these results showcase that additional stabilization via material design strategies will be required to induce a general departure from inverse stability-activity relationships among the transition metal oxide catalysts to ultimately grant access to the full range of available oxides for OER catalysis.

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Section: Atomistic Understanding Of Activity and Degradation Relies O...mentioning

confidence: 99%

Activity-Stability Relationships in Oxide Electrocatalysts for Water Electrolysis

et al. 2022

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“…[5][6][7][8][9][10][11][12][13] In some cases, depletion layer. [29] Thickness-dependent strain effects in thin films might also lead to corresponding changes to the electronic structures, impacting activity. [30][31][32][33] Missing, however, is a systematic understanding of how the thickness of a conductive oxide can impact OER activity and how such trends might depend on the nature of the underlying support.…”

Section: Introductionmentioning

confidence: 99%

Contribution of the Sub‐Surface to Electrocatalytic Activity in Atomically Precise La_0.7Sr_0.3MnO₃ Heterostructures

Lee

Adiga

Lee

et al. 2021

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the redox of these metals during cycling, such as in RuO 2 [14] and Ni-based oxides, [15] can be used to estimate their surface concentration. The density of active sites is often simply approximated by the exposed geometric surface area (measured by, e.g., microscopy or N 2 adsorption [16] ) or the electrochemical surface area (ECSA) by assumptions regarding intrinsic capacitance. [15,[17][18][19] However, all of these normalization approaches imply that electrochemical activity is governed exclusively by the terminal surface layer of the oxide, without serious consideration of sub-surface layers that may influence activity as well.Size effects in the OER activity of nanoparticles, [20,21] thickness-dependent effects in thin films, [22] and substrate-dependent effects in 2D materials [23] imply that while a catalytic reaction occurs at the catalyst/electrolyte interface, the supporting layers of a catalyst (and/or its support) can influence activity as well. For oxides, these size effects can include manipulating the ability of transition metal sites to oxidize prior to the onset of OER. [20,21] Thickness effects can additionally include charge transfer to/from a support, [24][25][26] quantum tunneling through ultra-thin layers, [27,28] and formation of a Electrocatalytic reactions are known to take place at the catalyst/electrolyte interface. Whereas recent studies of size-dependent activity in nanoparticles and thickness-dependent activity of thin films imply that the sub-surface layers of a catalyst can contribute to the catalytic activity as well, most of these studies consider actual modification of the surfaces. In this study, the role of catalytically active sub-surface layers was investigated by employing atomicscale thickness control of the La 0.7 Sr 0.3 MnO 3 (LSMO) films and heterostructures, without altering the catalyst/electrolyte interface. The activity toward the oxygen evolution reaction (OER) shows a non-monotonic thickness dependence in the LSMO films and a continuous screening effect in LSMO/SrRuO 3 heterostructures. The observation leads to the definition of an "electrochemically-relevant depth" on the order of 10 unit cells. This study on the electrocatalytic activity of epitaxial heterostructures provides new insight in designing efficient electrocatalytic nanomaterials and core-shell architectures.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/smll.202103632.

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“…12,14,29,30 Furthermore, heterostructure engineering was demonstrated to successfully enhance the OER reaction kinetics while maintaining a good chemical stability toward the surface oxidation. 28,31 Therefore, the thin film electrocatalysts were proved to be useful not only in understanding reaction mechanisms but also in designing and fabricating oxide electrocatalysts with an excellent activity and stability. Generally, the electrocatalytic activity of CoObased electrocatalysts is limited by their intrinsic weak electronic conductivity.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, thin film electrocatalysts were studied for exploring structure–activity relationships of the oxide electrocatalysts. − Advanced thin film growth techniques, such as pulsed laser deposition and sputtering, were adopted to understand and control those factors, such as crystal orientation, strain, and stoichiometry, influencing the electrocatalytic activity of the oxide catalysts. ,,, Furthermore, heterostructure engineering was demonstrated to successfully enhance the OER reaction kinetics while maintaining a good chemical stability toward the surface oxidation. , Therefore, the thin film electrocatalysts were proved to be useful not only in understanding reaction mechanisms but also in designing and fabricating oxide electrocatalysts with an excellent activity and stability. Generally, the electrocatalytic activity of CoO-based electrocatalysts is limited by their intrinsic weak electronic conductivity .…”

Section: Introductionmentioning

confidence: 99%

Enhanced Oxygen Evolution Activity of CoO–La_0.7Sr_0.3MnO_3−δ Heterostructured Thin Film

Xie

Shi

et al. 2020

ACS Appl. Energy Mater.

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The design and fabrication of highly efficient oxygen evolution reaction (OER) electrocatalysts is crucial for further development of electrochemical conversion devices. In this paper, the pulsed laser deposition technique was first used to fabricate high quality and well-defined CoO−La 0.7 Sr 0.3 MnO 3−δ (LSMO) heterostructured electrocatalysts. The current density was about 70 and 20 times larger with respect to single-phase CoO and LSMO thin film electrocatalysts, respectively. The enhancement of electrocatalytic activity was investigated in detail by using electrochemical and X-ray photoemission/absorption spectroscopies. The introduction of the LSMO intermediate layer not only promoted charge transfer kinetics but also resulted in a larger Co 3+ /Co 2+ ratio due to the partial oxidation of the CoO layer during film growth. The design of coatings with a tunable oxygen electrocatalytic activity implementing the heterostructure engineering approach was demonstrated.

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Enhanced Stability and Thickness‐Independent Oxygen Evolution Electrocatalysis of Heterostructured Anodes with Buried Epitaxial Bilayers

Cited by 18 publications

References 35 publications

Activity-Stability Relationships in Oxide Electrocatalysts for Water Electrolysis

Activity-Stability Relationships in Oxide Electrocatalysts for Water Electrolysis

Contribution of the Sub‐Surface to Electrocatalytic Activity in Atomically Precise La_0.7Sr_0.3MnO₃ Heterostructures

Enhanced Oxygen Evolution Activity of CoO–La_0.7Sr_0.3MnO_3−δ Heterostructured Thin Film

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Enhanced Stability and Thickness‐Independent Oxygen Evolution Electrocatalysis of Heterostructured Anodes with Buried Epitaxial Bilayers

Cited by 18 publications

References 35 publications

Activity-Stability Relationships in Oxide Electrocatalysts for Water Electrolysis

Activity-Stability Relationships in Oxide Electrocatalysts for Water Electrolysis

Contribution of the Sub‐Surface to Electrocatalytic Activity in Atomically Precise La0.7Sr0.3MnO3 Heterostructures

Enhanced Oxygen Evolution Activity of CoO–La0.7Sr0.3MnO3−δ Heterostructured Thin Film

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Contribution of the Sub‐Surface to Electrocatalytic Activity in Atomically Precise La_0.7Sr_0.3MnO₃ Heterostructures

Enhanced Oxygen Evolution Activity of CoO–La_0.7Sr_0.3MnO_3−δ Heterostructured Thin Film