Murielle Schreck

Last Name

Schreck

First Name

Murielle

ORCID

0000-0001-8932-9184

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Publications 1 - 7 of 7

Impregnation of Cellulose Fibers with Copper Colloids and Their Processing into Electrically Conductive Paper
Schreck, Murielle; Deshmukh, Rupali; Tervoort, Elena; et al. (2022)
Chemistry of Materials
The use of biodegradable and nontoxic cellulose as a renewable alternative to plastic in electronics is a promising way to decrease the environmental pollution. Unfortunately, cellulose lacks one of the key properties for such applications, namely, electrical conductivity. Here, we report the complete impregnation of macroscopic cellulose fibers with copper colloids using a simple, fast, gram-scalable, electroless, and noble metal catalyst-free liquid-phase approach. By varying the stepwise addition of a precursor to the ongoing reaction, the amount of copper colloids inside the cellulose fibers and thus the electrical conductivity of the final product can be controlled. A simple vacuum filtration makes it possible to process the copper-impregnated fibers into self-supporting, paper-like membranes, whose electrical conductivity can be further improved by slight pressing. The fiber-like morphology in these papers is fully preserved after pressing, leading to a high in-plane conductivity of 10′105 ± 751 S/m. By equipping cellulose with electrical conductivity, the functional properties of this renewable material are significantly extended, making it now attractive for a wide range of emerging applications in electronics and electrocatalysis.
Gas-Phase Nitrogen Doping of Monolithic TiO2 Nanoparticle-Based Aerogels for Efficient Visible Light-Driven Photocatalytic H2 Production
Kwon, Junggou; Choi, Kyoungjun; Schreck, Murielle; et al. (2021)
ACS Applied Materials & Interfaces
The development of visible light-active photocatalysts is essential for increasing the conversion efficiency of solar energy into hydrogen (H2). Here, we present a facile method for nitrogen doping of monolithic titanium dioxide (TiO2) nanoparticle-based aerogels to activate them for visible light. Plasma-enhanced chemical vapor deposition at low temperature enables efficient incorporation of nitrogen into preformed TiO2 aerogels without compromising their advantageous intrinsic characteristics such as large surface area, extensive porosity, and nanoscale properties of the semiconducting building blocks. By balancing the dopant concentration and the defects, the nitridation improves optical absorption and charge separation efficiency. The nitrogen-doped TiO2 nanoparticle-based aerogels loaded with palladium (Pd) nanoparticles show a significant enhancement in visible light-driven photocatalytic H2 production (3.1 mmol h–1 g–1) with excellent stability over 5 days. With this method, we introduce a powerful tool to tune the properties of nanoparticle-based aerogels after synthesis for a specific application, as exemplified by visible light-driven H2 production.
Monolithic metal-containing TiO2 aerogels assembled from crystalline pre-formed nanoparticles as efficient photocatalysts for H2 generation
Luna, Ana L.; Matter, Fabian; Schreck, Murielle; et al. (2020)
Applied Catalysis B: Environmental
Nanoparticle-based aerogels are 3-dimensional (3D) assemblies of macroscopic size that maintain the intrinsic properties of the initial nanoparticles. Accordingly, they bear immense potential to become an emerging platform for designing new and efficient photocatalysts. However, to take full advantage of this strategy, understanding of the multiscale processes occurring in such 3D-architectures is essential. Here, we prepared aerogels by co-assembling spherical Au, Pd, and PdAu with TiO2 nanoparticles and investigated their photocatalytic properties for hydrogen generation. During gelation, the anatase nanoparticles undergo oriented attachment, homogeneously entrapping the metal nanoparticles in the growing network. The aerogels offer a high porosity with a mean pore size of ca. 34 nm and a large surface area of about 450 m2 g−1. The porous structure enhances the light-harvesting, reagent transport, and electron migration process, generating 3.5-fold more hydrogen in comparison to the corresponding powders.
Porous Silica Microspheres with Immobilized Titania Nanoparticles for In-Flow Solar-Driven Purification of Wastewater
Marques, Ana C.; Vale, Mario; Vicente, Daniel; et al. (2021)
Global Challenges
In this paper, inorganic silica microspheres with interconnected macroporosity are tested as a platform for designing robust and efficient photocatalytic systems for a continuous flow reactor, enabling a low cost and straightforward purification of wastewater through solar-driven photocatalysis. The photocatalytically active microspheres are prepared by wet impregnation of porous silica scaffolds with Trizma-functionalized anatase titania (TiO2) nanoparticles (NPs). NPs loading of 22 wt% is obtained in the form of a thin and well-attached layer, covering the external surface of the microspheres as well as the internal surface of the pores. The TiO2 loading leads to an increase of the specific surface area by 26%, without impacting the typically interconnected macroporosity (approximate to 60%) of the microspheres, which is essential for an efficient flow of the pollutant solution during the photocatalytic tests. These are carried out in a liquid medium for the decomposition of methyl orange and paracetamol. In addition to photocatalytic activity under continuous flow, the microspheres offer the advantage that they can be easily removed from the reaction medium, which is an appealing aspect for industrial applications. In this work, the typical issues of TiO2 NPs photocatalysts are circumvented, without the need for elaborate chemistries, and for low availability and expensive raw materials.
Design Considerations for Aerogels as 3D Gas Phase Photocatalysts
Schreck, Murielle (2021)
Correction to Photocatalytic Gas Phase Reactions
Schreck, Murielle; Niederberger, Markus (2019)
Chemistry of Materials
3D Printed Scaffolds for Monolithic Aerogel Photocatalysts with Complex Geometries
Schreck, Murielle; Kleger, Nicole; Matter, Fabian; et al. (2021)
Small
Monolithic aerogels composed of crystalline nanoparticles enable photocatalysis in three dimensions, but they suffer from low mechanical stability and it is difficult to produce them with complex geometries. Here, an approach to control the geometry of the photocatalysts to optimize their photocatalytic performance by introducing carefully designed 3D printed polymeric scaffolds into the aerogel monoliths is reported. This allows to systematically study and improve fundamental parameters in gas phase photocatalysis, such as the gas flow through and the ultraviolet light penetration into the aerogel and to customize its geometric shape to a continuous gas flow reactor. Using photocatalytic methanol reforming as a model reaction, it is shown that the optimization of these parameters leads to an increase of the hydrogen production rate by a factor of three from 400 to 1200 µmol g−1 h−1. The rigid scaffolds also enhance the mechanical stability of the aerogels, lowering the number of rejects during synthesis and facilitating handling during operation. The combination of nanoparticle-based aerogels with 3D printed polymeric scaffolds opens up new opportunities to tailor the geometry of the photocatalysts for the photocatalytic reaction and for the reactor to maximize overall performance without necessarily changing the material composition.

Publications 1 - 7 of 7

Murielle Schreck

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