TY - JOUR

T1 - Nanostructured Ir-based electrocatalysts for oxygen evolution prepared by galvanic displacement of Co and Ni

AU - Holde, Freja Bech

AU - Sebastián-Pascual, Paula

AU - Dalby, Kim Nicole

AU - Gómez, Elvira

AU - Escudero-Escribano, María

N1 - Funding Information: M.E.E. acknowledges the Villum Foundation for financial support through a Villum Young Investigator Grant (project number: 19142). This work was also supported by the Independent Research Fund Denmark through the DFF-Research Project1 (Thematic Research, green transition) grant with number: 0217-00213A. We acknowledge support from the Danish National Research Foundation and center for High Entropy Alloy Catalysis (DNRF-149, CHEAC). We also acknowledge Theis Brock-Nannestad from the University of Copenhagen, for providing facilities and performing most of the ICP measurements of the Ir samples, and Kim Degn Jensen who measured one of the ICP samples. We also acknowledge Hanne Falsig from Topsoe AS for providing valuable discussions. Funding Information: M.E.E. acknowledges the Villum Foundation for financial support through a Villum Young Investigator Grant (project number: 19142). This work was also supported by the Independent Research Fund Denmark through the DFF-Research Project1 (Thematic Research, green transition) grant with number: 0217-00213A. We acknowledge support from the Danish National Research Foundation and center for High Entropy Alloy Catalysis (DNRF-149, CHEAC). We also acknowledge Theis Brock-Nannestad from the University of Copenhagen, for providing facilities and performing most of the ICP measurements of the Ir samples, and Kim Degn Jensen who measured one of the ICP samples. We also acknowledge Hanne Falsig from Topsoe AS for providing valuable discussions. Publisher Copyright: © 2023

PY - 2023

Y1 - 2023

N2 - Proton exchange membrane (PEM) electrolysers are promising devices to produce hydrogen as a green fuel. Currently, this technology is limited by the sluggish kinetics of the oxygen evolution reaction (OER). In this work, we describe an environmentally safe method for the preparation of Ir oxide thin films (IrO2) for OER. Electrodeposition of Co and Ni was performed in the non-toxic choline chloride:urea deep eutectic solvent (ChCl:urea DES), followed by galvanic displacement reaction (GDR) of Co and Ni by Ir(IV). We evaluated how the GDR conditions, such as the metal replaced (Co or Ni), time and temperature affect both the activity and stability of the deposited IrO2 films on gold substrates. We observed that GDR of Ni at 90 °C induces morphological changes on the IrO2 nanostructures which resulted in higher activity and stability towards OER. We highlight that not only reducing mass loadings of Ir but also tuning the surface morphology and structure controlling the synthesis preparation, as well as investigating the role of the substrate, are key to design more active and stable OER electrocatalysts.

AB - Proton exchange membrane (PEM) electrolysers are promising devices to produce hydrogen as a green fuel. Currently, this technology is limited by the sluggish kinetics of the oxygen evolution reaction (OER). In this work, we describe an environmentally safe method for the preparation of Ir oxide thin films (IrO2) for OER. Electrodeposition of Co and Ni was performed in the non-toxic choline chloride:urea deep eutectic solvent (ChCl:urea DES), followed by galvanic displacement reaction (GDR) of Co and Ni by Ir(IV). We evaluated how the GDR conditions, such as the metal replaced (Co or Ni), time and temperature affect both the activity and stability of the deposited IrO2 films on gold substrates. We observed that GDR of Ni at 90 °C induces morphological changes on the IrO2 nanostructures which resulted in higher activity and stability towards OER. We highlight that not only reducing mass loadings of Ir but also tuning the surface morphology and structure controlling the synthesis preparation, as well as investigating the role of the substrate, are key to design more active and stable OER electrocatalysts.

KW - Deep eutectic solvent

KW - Electrodeposition

KW - Galvanic displacement reaction

KW - Iridium oxide

KW - Oxygen evolution reaction

U2 - 10.1016/j.electacta.2023.143058

DO - 10.1016/j.electacta.2023.143058

M3 - Journal article

AN - SCOPUS:85169004544

VL - 467

JO - Electrochimica Acta

JF - Electrochimica Acta

SN - 0013-4686

M1 - 143058

ER -