Nickel Structures as a Template Strategy to Create Shaped Iridium Electrocatalysts for Electrochemical Water Splitting

ACS Applied Materials & Interfaces, vol. 13, pp. 13576–13585

Abstract

Low-cost, highly active, and highly stable catalysts are desired for the generation of hydrogen and oxygen using water electrolyzers. To enhance the kinetics of the oxygen evolution reaction in an acidic medium, it is of paramount importance to redesign iridium electrocatalysts into novel structures with organized morphology and high surface area. Here, we report on the designing of a well-defined and highly active hollow nanoframe based on iridium. The synthesis strategy was to control the shape of nickel nanostructures on which iridium nanoparticles will grow. After the growth of iridium on the surface, the next step was to etch the nickel core to form the NiIr hollow nanoframe. The etching procedure was found to be significant in controlling the hydroxide species on the iridium surface and by that affecting the performance. The catalytic performance of the NiIr hollow nanoframe was studied for oxygen evolution reaction and shows 29 times increased iridium mass activity compared to commercially available iridium-based catalysts. Our study provides novel insights to control the fabrication of iridium-shaped catalysts using 3d transition metal as a template and via a facile etching step to steer the formation of hydroxide species on the surface. These findings shall aid the community to finally create stable iridium alloys for polymer electrolyte membrane water electrolyzers, and the strategy is also useful for many other electrochemical devices such as batteries, fuel cells, sensors, and solar organic cells.

Authors 7

1. Seong-Eun Park

   Forschungszentrum Jülich

   Affiliation as printed

   Institute of Energy and Climate Research, Electrochemical Process Engineering (IEK-14), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany

2. Meital Shviro corresponding

   Forschungszentrum Jülich

   Affiliation as printed

   Institute of Energy and Climate Research, Electrochemical Process Engineering (IEK-14), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany

3. Heinrich Hartmann

   Forschungszentrum Jülich

   Affiliation as printed

   Central Institute for Engineering, Electronics and Analytics (ZEA-3), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany

4. Astrid Besmehn

   Forschungszentrum Jülich

   Affiliation as printed

   Central Institute for Engineering, Electronics and Analytics (ZEA-3), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany

5. Joachim Mayer Aachen

   Forschungszentrum Jülich · RWTH Aachen University

   Affiliation as printed

   ER-C 2, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany

   GFE, RWTH Aachen University, 52074 Aachen, Germany

6. Detlef Stolten Aachen Chair for Fuel Cells

   Forschungszentrum Jülich · RWTH Aachen University

   Affiliation as printed

   Chair for Fuel Cells, RWTH Aachen University, 52062 Aachen, Germany

   Institute of Energy and Climate Research, Techno-economic Systems Analysis (IEK-3), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany

7. Marcelo Carmo

   Forschungszentrum Jülich · Queen's University

   Affiliation as printed

   Institute of Energy and Climate Research, Electrochemical Process Engineering (IEK-14), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany

   Mechanical and Materials Engineering, Queen’s University, Kingston, Ontario K7L 3N6, Canada