Cryoaerogels and Cryohydrogels as Efficient Electrocatalysts

authored by

Dennis Müller, Dániel Zámbó, Dirk Dorfs, Nadja C. Bigall

Abstract

Additive-free cryoaerogel coatings from noble metal nanoparticles are prepared and electrochemically investigated. By using liquid nitrogen or isopentane as cooling medium, two different superstructures are created for each type of noble metal nanoparticle. These materials (made from the same amount of particles) have superior morphological and catalytic properties as compared to simply immobilized, densely packed nanoparticles. The morphology of all materials is investigated with scanning electron microscopy (SEM). Electrochemically active surface areas (ECSAs) are calculated from cyclic voltammetry measurements. The catalytic activity is studied for the ethanol oxidation reaction (EOR). Both are found to be increased for superstructured materials prepared by cryoaerogelation. Furthermore, cryoaerogels with cellular to dendritic structure that arise from freezing with isopentane show the best catalytic performance and highest ECSA. Moreover, as a new class of materials, cryohydrogels are created for the first time by thawing flash-frozen nanoparticle solutions. Structure and morphology of these materials match with the corresponding types of cryoaerogels and are confirmed via SEM. Even the catalytic activity in EOR is in accordance with the results from cryoaerogel coatings. As a proof of concept, this approach offers a novel platform towards the easier and faster production of cryogelated materials for wet-chemical applications.

Organisation(s)

Institute of Physical Chemistry and Electrochemistry
Laboratory of Nano and Quantum Engineering
PhoenixD: Photonics, Optics, and Engineering - Innovation Across Disciplines

Type

Article

Journal

SMALL

Volume

17

ISSN

1613-6810

Publication date

06.05.2021

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Biotechnology, Biomaterials, Chemistry(all), Materials Science(all)

Electronic version(s)

https://doi.org/10.1002/smll.202007908 (Access: Open)