Hannah-Noa Barad - Video Lecture

Hannah-Noa Barad - Video Lecture

IVS-IPSTA 2020 Online Conference December 13, 2020

Energy and Catalysis Session
Session chair:
Malachi Noked

Bar-Ilan University

 

Composition and nanostructure variation in a multinary materials library: effect on electrocatalytic properties of oxygen evolution

Hannah-Noa Barad

Max Planck Institute for Intelligent Systems, Heisenbergstr,
Stuttgart, German


Abstract


Combinatorial materials science (CMS) is a highly promising method for fast discovery of new functional materials, such as photoabsorbers, shape-memory alloys, and luminescent materials. CMS has been used to form thin films with composition and thickness gradients, consequently, synthesizing, on a single substrate, a range of samples with systematically varying properties, which is the first step in finding new materials and device structures. Apart from the composition or thickness, film morphology or nanostructuring can be especially important for an assortment of applications ranging from catalysis and photovoltaics to magnetic materials, as morphology governs the chemical reactivity, determines the surface area, and is important for charge mobility and recombination processes. However, heretofore CMS did not encompass film morphology as a study parameter.

Here we describe how we vary nano-scale morphology and material composition at the same time using an adapted shadow growth method based on glancing angle deposition (GLAD), which we developed, eliminating the commonly used wet chemical steps for nanostructure synthesis. In a one-step well-controlled growth we quickly obtain a large number of nano-columnar structures, including nanorods, nanohelices, and nano-zigzags, with varying material compositions. We use this method to fabricate a multinary elemental library, where each material has an impact on the resulting nanostructure as well and the chemical composition and oxidation state. After investigating the physical and chemical properties of the library, we then examine it as an electrocatalyst for oxygen evolution reaction (OER). The OER activity shows a dependence on the nanostructuring of the library as well as on the elemental compositional variation. By using the adapted GLAD-CMS method, we are able to gain insights that the standard experimental techniques would not be able to achieve. This method constitutes an integrated approach for discovering new materials and structures for a multitude of applications in many scientific fields.