Design and Synthesis of Ir/Ru Pyrochlore Catalysts for the Oxygen Evolution Reaction Based on Their Bulk Thermodynamic Properties

Daniel F. Abbott, Rebecca K. Pittkowski, Kateřina Macounová, Roman Nebel, Elena Marelli, Emiliana Fabbri, Ivano E. Castelli, Petr Krtil, Thomas J. Schmidt

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Density functional theory (DFT) has proven to be an invaluable and effective tool for identifying highly active electrocatalysts for the oxygen evolution reaction (OER). Herein, we take a computational approach to first identify a series of rare-earth pyrochlore oxides based on Ir and Ru as potential OER catalysts. The DFT-based phase diagrams, Pourbaix diagrams (E vs pH), projected density of states, and band energy diagrams were used to identify prospective OER catalysts based on rare-earth Ir and Ru pyrochlores. The predicted materials were synthesized using the spray-freeze freeze-drying approach to afford nanoparticulate oxides conforming to the pyrochlore structural type A2B2O7 where A = Nd, Gd, or Yb and B = Ir or Ru. In agreement with the computed Pourbaix diagrams, the materials were found to be moderately stable under OER conditions. All prepared materials show higher stability as compared to the benchmark IrO2 catalyst, and the OER mass activity of Yb2Ir2O7 and the ruthenate pyrochlores (Nd2Ru2O7, Gd2Ru2O7, and Yb2Ru2O7) were also found to exceed those of the benchmark IrO2 catalyst. We find that the OER activity of each pyrochlore series (i.e., iridate or ruthenate) generally improves as the size of the A-site cation decreases, indicating that maintaining control over the structure can be used to influence the electrocatalytic properties.
Original languageEnglish
JournalACS Applied Materials and Interfaces
Volume11
Issue number41
Pages (from-to)37748-37760
ISSN1944-8244
DOIs
Publication statusPublished - 2019

Keywords

  • Oxygen evolution
  • Pyrochlore
  • DFT
  • Iridium
  • Ruthenium
  • Lanthanide

Cite this

Abbott, D. F., Pittkowski, R. K., Macounová, K., Nebel, R., Marelli, E., Fabbri, E., ... Schmidt, T. J. (2019). Design and Synthesis of Ir/Ru Pyrochlore Catalysts for the Oxygen Evolution Reaction Based on Their Bulk Thermodynamic Properties. ACS Applied Materials and Interfaces, 11(41), 37748-37760. https://doi.org/10.1021/acsami.9b13220
Abbott, Daniel F. ; Pittkowski, Rebecca K. ; Macounová, Kateřina ; Nebel, Roman ; Marelli, Elena ; Fabbri, Emiliana ; Castelli, Ivano E. ; Krtil, Petr ; Schmidt, Thomas J. / Design and Synthesis of Ir/Ru Pyrochlore Catalysts for the Oxygen Evolution Reaction Based on Their Bulk Thermodynamic Properties. In: ACS Applied Materials and Interfaces. 2019 ; Vol. 11, No. 41. pp. 37748-37760.
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abstract = "Density functional theory (DFT) has proven to be an invaluable and effective tool for identifying highly active electrocatalysts for the oxygen evolution reaction (OER). Herein, we take a computational approach to first identify a series of rare-earth pyrochlore oxides based on Ir and Ru as potential OER catalysts. The DFT-based phase diagrams, Pourbaix diagrams (E vs pH), projected density of states, and band energy diagrams were used to identify prospective OER catalysts based on rare-earth Ir and Ru pyrochlores. The predicted materials were synthesized using the spray-freeze freeze-drying approach to afford nanoparticulate oxides conforming to the pyrochlore structural type A2B2O7 where A = Nd, Gd, or Yb and B = Ir or Ru. In agreement with the computed Pourbaix diagrams, the materials were found to be moderately stable under OER conditions. All prepared materials show higher stability as compared to the benchmark IrO2 catalyst, and the OER mass activity of Yb2Ir2O7 and the ruthenate pyrochlores (Nd2Ru2O7, Gd2Ru2O7, and Yb2Ru2O7) were also found to exceed those of the benchmark IrO2 catalyst. We find that the OER activity of each pyrochlore series (i.e., iridate or ruthenate) generally improves as the size of the A-site cation decreases, indicating that maintaining control over the structure can be used to influence the electrocatalytic properties.",
keywords = "Oxygen evolution, Pyrochlore, DFT, Iridium, Ruthenium, Lanthanide",
author = "Abbott, {Daniel F.} and Pittkowski, {Rebecca K.} and Kateřina Macounov{\'a} and Roman Nebel and Elena Marelli and Emiliana Fabbri and Castelli, {Ivano E.} and Petr Krtil and Schmidt, {Thomas J.}",
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Abbott, DF, Pittkowski, RK, Macounová, K, Nebel, R, Marelli, E, Fabbri, E, Castelli, IE, Krtil, P & Schmidt, TJ 2019, 'Design and Synthesis of Ir/Ru Pyrochlore Catalysts for the Oxygen Evolution Reaction Based on Their Bulk Thermodynamic Properties', ACS Applied Materials and Interfaces, vol. 11, no. 41, pp. 37748-37760. https://doi.org/10.1021/acsami.9b13220

Design and Synthesis of Ir/Ru Pyrochlore Catalysts for the Oxygen Evolution Reaction Based on Their Bulk Thermodynamic Properties. / Abbott, Daniel F.; Pittkowski, Rebecca K.; Macounová, Kateřina; Nebel, Roman; Marelli, Elena; Fabbri, Emiliana; Castelli, Ivano E.; Krtil, Petr; Schmidt, Thomas J.

In: ACS Applied Materials and Interfaces, Vol. 11, No. 41, 2019, p. 37748-37760.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Design and Synthesis of Ir/Ru Pyrochlore Catalysts for the Oxygen Evolution Reaction Based on Their Bulk Thermodynamic Properties

AU - Abbott, Daniel F.

AU - Pittkowski, Rebecca K.

AU - Macounová, Kateřina

AU - Nebel, Roman

AU - Marelli, Elena

AU - Fabbri, Emiliana

AU - Castelli, Ivano E.

AU - Krtil, Petr

AU - Schmidt, Thomas J.

PY - 2019

Y1 - 2019

N2 - Density functional theory (DFT) has proven to be an invaluable and effective tool for identifying highly active electrocatalysts for the oxygen evolution reaction (OER). Herein, we take a computational approach to first identify a series of rare-earth pyrochlore oxides based on Ir and Ru as potential OER catalysts. The DFT-based phase diagrams, Pourbaix diagrams (E vs pH), projected density of states, and band energy diagrams were used to identify prospective OER catalysts based on rare-earth Ir and Ru pyrochlores. The predicted materials were synthesized using the spray-freeze freeze-drying approach to afford nanoparticulate oxides conforming to the pyrochlore structural type A2B2O7 where A = Nd, Gd, or Yb and B = Ir or Ru. In agreement with the computed Pourbaix diagrams, the materials were found to be moderately stable under OER conditions. All prepared materials show higher stability as compared to the benchmark IrO2 catalyst, and the OER mass activity of Yb2Ir2O7 and the ruthenate pyrochlores (Nd2Ru2O7, Gd2Ru2O7, and Yb2Ru2O7) were also found to exceed those of the benchmark IrO2 catalyst. We find that the OER activity of each pyrochlore series (i.e., iridate or ruthenate) generally improves as the size of the A-site cation decreases, indicating that maintaining control over the structure can be used to influence the electrocatalytic properties.

AB - Density functional theory (DFT) has proven to be an invaluable and effective tool for identifying highly active electrocatalysts for the oxygen evolution reaction (OER). Herein, we take a computational approach to first identify a series of rare-earth pyrochlore oxides based on Ir and Ru as potential OER catalysts. The DFT-based phase diagrams, Pourbaix diagrams (E vs pH), projected density of states, and band energy diagrams were used to identify prospective OER catalysts based on rare-earth Ir and Ru pyrochlores. The predicted materials were synthesized using the spray-freeze freeze-drying approach to afford nanoparticulate oxides conforming to the pyrochlore structural type A2B2O7 where A = Nd, Gd, or Yb and B = Ir or Ru. In agreement with the computed Pourbaix diagrams, the materials were found to be moderately stable under OER conditions. All prepared materials show higher stability as compared to the benchmark IrO2 catalyst, and the OER mass activity of Yb2Ir2O7 and the ruthenate pyrochlores (Nd2Ru2O7, Gd2Ru2O7, and Yb2Ru2O7) were also found to exceed those of the benchmark IrO2 catalyst. We find that the OER activity of each pyrochlore series (i.e., iridate or ruthenate) generally improves as the size of the A-site cation decreases, indicating that maintaining control over the structure can be used to influence the electrocatalytic properties.

KW - Oxygen evolution

KW - Pyrochlore

KW - DFT

KW - Iridium

KW - Ruthenium

KW - Lanthanide

U2 - 10.1021/acsami.9b13220

DO - 10.1021/acsami.9b13220

M3 - Journal article

VL - 11

SP - 37748

EP - 37760

JO - A C S Applied Materials and Interfaces

JF - A C S Applied Materials and Interfaces

SN - 1944-8244

IS - 41

ER -