TY - JOUR

T1 - Cryoaerogels and Cryohydrogels as Efficient Electrocatalysts

AU - Müller, Dennis

AU - Zámbó, Dániel

AU - Dorfs, Dirk

AU - Bigall, Nadja C.

N1 - Funding Information: The project has in parts been funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy within the Cluster of Excellence PhoenixD (EXC 2122, Project ID 390833453). The authors also would like to acknowledge the DFG (grant agreement BI 1708/4-1 & DO 1580/5-1), the European Research Council (European Union's Horizon 2020 research and innovation program, grant agreement 714429), and the German Federal Ministry of Education and Research (BMBF) within the framework of the program NanoMatFutur (support code 03X5525) for financial support. D.M. is thankful for financial support from the Hannover School for Nanotechnology (hsn) and the Graduiertenakademie of the Leibniz Universit?t Hannover. The authors moreover thank Armin Feldhoff and J?rgen Caro for providing the SEM facility as well as the Institute for Inorganic Chemistry for providing the ICP-OES facility. Open access funding enabled and organized by Projekt DEAL.

PY - 2021/5/6

Y1 - 2021/5/6

N2 - 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.

AB - 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.

KW - aerogel coatings

KW - cryoaerogels

KW - cryohydrogels

KW - electrocatalysis

KW - ethanol oxidation

UR - http://www.scopus.com/inward/record.url?scp=85102730912&partnerID=8YFLogxK

U2 - 10.1002/smll.202007908

DO - 10.1002/smll.202007908

M3 - Article

AN - SCOPUS:85102730912

VL - 17

JO - SMALL

JF - SMALL

SN - 1613-6810

IS - 18

M1 - 2007908

ER -