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Nanoparticle-based aerogels for photocatalytic gas phase reactions

English title Nanoparticle-based aerogels for photocatalytic gas phase reactions
Applicant Niederberger Markus
Number 184842
Funding scheme Project funding (Div. I-III)
Research institution Departement Materialwissenschaft ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Inorganic Chemistry
Start/End 01.04.2019 - 31.03.2022
Approved amount 453'240.00
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All Disciplines (2)

Discipline
Inorganic Chemistry
Material Sciences

Keywords (5)

Photocatalysis; Aerogels; Nanoparticles; Metal oxides; Self-assembly

Lay Summary (German)

Lead
In diesem Projekt geht es darum, aus Nanopartikeln Aerogele (poröse, schwammartige Materialien) herzustellen, die sich für photokatalytische Gasphasenreaktionen wie CO2 Reduktion eignen. Ausserdem soll ein geeigneter Reaktor entwickelt werden, der es erlaubt, die Aerogele effizient zu beleuchten und die Reaktionsprodukte der Gasphasenreaktionen zu analysieren.
Lay summary

Aerogele sind hochporöse, schwammartige Materialien. Die meisten Aerogele bestehen aus Silica und ihre Anwendungen sind auf die thermische Isolation beschränkt. In diesem Projekt geht es darum, Aerogele aus vorgeformten Nanopartikeln aufzubauen. Es gibt viele verschiedene Nanopartikel, die eine grosse Bandbreite an Funktionen abdecken. Damit lassen sich neuartige Aerogele herstellen, die auch völlig andere Anwendungsmöglichkeiten eröffnen. In diesem Projekt konzentrieren wir uns auf Nanopartikel, die photokatalytische Eigenschaften haben, also Nanopartikel, die mit Hilfe von Licht chemische Reaktionen unterstützen können. Da Aerogele in Flüssigkeiten pulverisieren, werden wir uns auf Reaktionen in der Gasphase konzentrieren. Dazu müssen die Aerogele aber mechanisch stabiler werden. Eine Möglichkeit, dies zu erreichen, besteht in der Herstellung der Aerogele in einer Netzstruktur, die das Aerogel stabilisiert. Um die photokatalytische Aktivität der Aerogele zu studieren, wird im Rahmen dieses Projektes ein Reaktor entwickelt, der es erlaubt, die Aerogele mit Licht zu bestrahlen und der mit Analysegeräten verbunden ist, die die Charakterisierung der Reaktionsprodukte ermöglicht. Ziel ist es, neuartige Aerogele zu entwickeln, deren Zusammensetzung für bestimmte photokatalytische Gasphasenreaktionen optimiert worden sind. Wir werden versuchen, den Zusammenhang zwischen Zusammensetzung und Aktivität zu verstehen, so dass die Aerogele gezielt noch weiter verbessert werden können.

Direct link to Lay Summary Last update: 29.03.2019

Responsible applicant and co-applicants

Employees

Associated projects

Number Title Start Funding scheme
165888 Tailored synthesis of nanoparticle-based aerogel monoliths and their use in gas phase reactions 01.04.2016 Project funding (Div. I-III)

Abstract

The main goals of the previous project on “Tailored synthesis of nanoparticle-based aerogel monoliths and their use in gas phase reactions” (no. 200021_165888) were the development of synthesis routes to nanoparticle-based aerogels with high photocatalytic activity and the design of a reactor, enabling to perform photocatalytic gas phase reactions (mainly CO2 reduction) on monolithic aerogels. We succeeded in the preparation of a wide variety of nanoparticle-based aerogels and in the fabrication of a suitable reactor. At the same time, several new scientific questions and challenges opened up, which are addressed in the new proposal. The pronounced fragility of the aerogel monoliths makes their handling difficult and therefore their mechanical stability has to be increased. The photocatalytic efficiency not only depends on the composition and microstructure of the aerogels, but also on the reactor design. Two issues turned out to be particularly crucial: The illumination of the monolith in the tubular reactor and the characterization of the gas species after the photocatalytic reaction. Illumination and characterization of the products have to be improved and optimized. Furthermore, up to now mainly spherical nanoparticles were used as building blocks for the aerogels, although anisotropic particles like nanosheets or nanowires often show superior photocatalytic activity. Therefore, the library of building blocks has to be extended to 1- and 2-dimensional nanostructures. Other issues are the understanding of the charge carrier dynamics in the nanoparticles composing the aerogels and the role of organic residues in the aerogels. These aspects have to be carefully clarified in order to be able to systematically improve the photocatalytic performance of the aerogels. Finally, the question arises, if other photocatalytic gas phase reactions rather than CO2 reduction can be performed in the same experimental set-up.To tackle all these problems, we propose the following tasks. The mechanical stability will be improved either by minimizing microcracks formation during aerogel preparation or by gelling the nanoparticles inside a rigid scaffold. The influence of aerogel illumination will be studied by using adjustable light sources such as light emitting diodes (LEDs). To improve the reliability of the data regarding identification and quantity of organic reaction products, we will collaborate with an expert at ETH to enlarge our knowledge and we plan to invest in a mass spectrometer complementing our gas chromatography system. For the gelation of anisotropic building blocks we will adapt the procedures currently used for spherical nanoparticles. Time resolved microwave conductivity (TRMC) measurements will be applied to study the charge carrier lifetimes in the aerogels, which will help us to optimize the composition of the aerogels for a specific reaction. Potential interference of organic residues in the photocatalytic gas phase reaction will be investigated by employing labelled reactants. Finally, in the last part of the proposal, we will expand the photocatalytic gas phase reactions beyond CO2 reduction, targeting the decomposition of volatile organic compounds, which would significantly expand the application potential of our aerogel monoliths as photocatalysts.
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