Publications by authors named "Peter G Weidler"

This article is the second part of a study reporting the results of a novel carbon capture and utilization (CCU) process, which converts atmospheric CO into solid carbon materials. The CCU process combines direct air capture (DAC) with catalytic methanation, which is then followed by methane pyrolysis in a reactor filled with liquid tin. While Part 1 discussed the performance of the overall process and individual process steps regarding conversions and yields, Part 2 characterizes the solid carbon products obtained under various synthesis conditions.

View Article and Find Full Text PDF

Herein, the electrochemical properties and reaction mechanism of Li Ca V (PO ) /C (x = 0, 0.5, 1, and 1.5) as negative electrode materials for sodium-ion/potassium-ion batteries (SIBs/PIBs) are investigated.

View Article and Find Full Text PDF

Studies on reactions in solutions are often hampered by solvent effects. In addition, detailed investigation on kinetics is limited to the small temperature regime where the solvent is liquid. Here, we report the in situ spectroscopic observation of UV-induced photochemical reactions of aryl azides within a crystalline matrix in vacuum.

View Article and Find Full Text PDF
Article Synopsis
  • Polyanion-type phosphate materials, like MgV(PO4)3, show promise as negative electrodes for Li/Na/K-ion batteries, particularly due to their fast charging/discharging capabilities and distinct redox peaks.
  • The synthesized MgV(PO4)3/carbon composite (MgVP/C) exhibits high thermal stability and functions as a pseudocapacitive negative electrode; reactions vary based on the type of ion inserted due to differing ion sizes.
  • While MgVP/C provides strong initial capacities in lithium-ion batteries, it faces challenges like low initial efficiency and rapid capacity decay, highlighting the need for more research on its performance with sodium and potassium ions.
View Article and Find Full Text PDF

For the first time, a procedure has been established for the growth of surface-anchored metal-organic framework (SURMOF) copper(II) benzene-1,4-dicarboxylate (Cu-BDC) thin films of thickness control with single molecule accuracy. For this, we exploit the novel method solution atomic layer deposition (sALD). The sALD growth rate has been determined at 4.

View Article and Find Full Text PDF

This work establishes carbon nanofibre-mediated patterning of metal oxide nanostructures, through the combination of electrospinning and vapor-phase transport growth. Electrospinning of a suitable precursor with subsequent carbonization results in the patterning of catalyst gold nanoparticles embedded within carbon nanofibres. During vapor-phase transport growth, these nanofibres allow preferential growth of one-dimensional metal oxide nanostructures, which grow radially outward from the nanofibril axis, yielding a hairy caterpillar-like morphology.

View Article and Find Full Text PDF

Carbon origami enables the fabrication of lightweight and mechanically stiff 3D complex architectures of carbonaceous materials, which have a high potential to impact a wide range of applications positively. The precursor materials and their inherent microstructure play a crucial role in determining the properties of carbon origami structures. Here, non-porous polyaramid Nomex sheets and macroporous fibril cellulose sheets are explored as the precursor sheets for studying the effect of precursor nature and microstructure on the material and structural properties of the carbon origami structures.

View Article and Find Full Text PDF

Functionalization of metal-organic frameworks (MOFs) is critical in exploring their structural and chemical diversity for numerous potential applications. Herein, we report multiple approaches for the tandem postsynthetic modification (PSM) of various MOFs derived from Zr(IV), Al(III), and Zn(II). Our current work is based on our efforts to develop a wide range of MOF platforms with a dynamic functional nature that can be chemically switched via thermally triggered reversible Diels-Alder (DA) and hetero-Diels-Alder (HDA) ligations.

View Article and Find Full Text PDF

Magnetic stability of iron mineral phases is a key for their use as paleomagnetic information carrier and their applications in nanotechnology, and it critically depends on the size of the particles and their texture. Ferrimagnetic greigite (FeS) in nature and synthesized in the laboratory forms almost exclusively polycrystalline particles. Textural effects of inter-grown, nano-sized crystallites on the macroscopic magnetization remain unresolved because their experimental detection is challenging.

View Article and Find Full Text PDF

A method for the fabrication of flexible electrical circuits on polyaramid substrates is presented based on laser-induced carbonization followed by copper electroplating. Locally carbonized flexible sheets of polyaramid (Nomex), by laser radiation, create rough and highly porous microstructures that show a higher degree of graphitization than thermally carbonized Nomex sheets. The found recipe for laser-induced carbonization creates conductivities of up to ∼45 S cm, thereby exceeding that observed for thermally pyrolyzed materials (∼38 S cm) and laser carbon derived from Kapton using the same laser wavelength (∼35 S cm).

View Article and Find Full Text PDF

The European Union has proposed the value of 1 ng L as a drinking water quality standard for estradiol. With conventional technologies only partially removing estradiol, the investigation of novel alternatives is more than ever required. Tagliavini and Schäfer proposed that the use of a thin activated carbon layer combined with a membrane is worth considering.

View Article and Find Full Text PDF

The occurrence of micropollutants (MPs) including steroid hormones is a global environmental and health challenge. Carbon-based nanoparticles can be incorporated with water treatment processes to allow MP removal by adsorption. The aim was to compare the suitability of such nanoparticles (graphene, graphene oxide, carbon nanotubes and C) to adsorb steroid hormones for later incorporation in membrane composites.

View Article and Find Full Text PDF

Hysteresis in the sorption equilibrium influences the production process of many multicomponent material systems. Electrodes for Li-ion batteries consist of several materials, some of which exhibit hysteresis in their sorption equilibrium with water. The moisture content adsorbed and absorbed in the electrodes of the Li-ion battery turned out to be an issue for its electrochemical performance and is reduced in the post-drying process.

View Article and Find Full Text PDF

High quality, monolithic UiO-66-NH thin films on diverse solid substrates have been prepared via a low temperature liquid phase epitaxy method. The achievement of continuous films with low defect densities and great stability against high temperatures and hot water is proven, clearly outperforming other reported types of MOF thin films.

View Article and Find Full Text PDF

Invited for this month's cover is the group of Dr. Tawheed Hashem from the Karlsruhe Institute of Technology. The cover picture shows a successful synthesis of high quality, monolithic UiO-66-NH MOF thin films on diverse solid substrates via a low-temperature liquid phase epitaxy method.

View Article and Find Full Text PDF

Edible rice paper wrapper is found to be an interesting precursor of a porous and light-weight carbon material. During pyrolysis, material samples show significant differences in length change, displaying typical 20-25% shrinking in the in-plane directions, and strongly expanding (up to 500%) across their out-of-plane direction. This results in a template-free synthesis of a 3D network of cellular carbon material.

View Article and Find Full Text PDF

Migration of atoms in solids during diffusion-dependent reactions is relatively fast and generally not directly recordable in experiments. Here we present an experimental framework that includes fast differential scanning calorimetry to resolve cation-migration paths in crystalline solids using the reversible magneto-structural transition of 4C to 1C pyrrhotite as a testbed. The transition between these two polymorphic FeS phases at about 600 K is a diffusive process of vacancies, respectively of Fe in octahedral interstitial sites within a hexagonal close-packed lattice of sulfur, and it coincides with the Curie temperature of 4C pyrrhotite.

View Article and Find Full Text PDF

The development of methods for colloidal self-assembly on solid surfaces is important for many applications in biomedical sciences. Toward this goal, described is a versatile class of mesoporous silica nanoparticles (MSN) that contain on their surface various types of DNA molecules to enable their self-assembly into micropatterned surface architectures useful for cell studies. Monodisperse dye-doped MSN are synthesized by biphase stratification and functionalized with an aptamer oligonucleotide that serves as gatekeeper for the triggered release of encapsulated molecular cargo, such as fluorescent dye rhodamine B or the anticancer drug doxorubicin.

View Article and Find Full Text PDF

We describe a non-conventional, MOF-based approach with modified linkers to fabricate 3D Bi2O3 supracrystals. The nanoparticle (NP) assembly exhibits bcc-packing, which is difficult to achieve with other methods. The NPs possess a very narrow size distribution.

View Article and Find Full Text PDF
Article Synopsis
  • Understanding how dioxygen interacts with metal oxides is crucial for improving heterogeneous catalysis, with ceria being a key player.
  • This study uses surface science techniques to examine reactive dioxygen species on ceria's (110) and (100) surfaces, while finding that these species do not exist on the stable (111) surface.
  • The findings suggest that oxygen vacancies, which play a role in dioxygen activation, behave differently on various surface types, resolving debates about their locations and effects in ceria-based reactions.
View Article and Find Full Text PDF

We present the reversible Diels-Alder functionalization of metal organic frameworks (MOFs). Cyclopentadiene (Cp) functional MOFs are ligated with dienophiles to fabricate functional MOFs with a reprogrammable chemical nature. Our strategy thus constitutes an unprecedented concept for chemically dynamic MOFs able to be recoded.

View Article and Find Full Text PDF

The photoreactivity of ceria, a photochemically inert oxide with a large band gap, can be increased to competitive values by introducing defects. This previously unexplained phenomenon has been investigated by monitoring the UV-induced decomposition of N O on well-defined single crystals of ceria by using infrared reflection-absorption spectroscopy (IRRAS). The IRRAS data, in conjunction with theory, provide direct evidence that reducing the ceria(110) surface yields high photoreactivity.

View Article and Find Full Text PDF

Removal and interaction mechanisms of four different steroid micropollutants, estrone (E1), estradiol (E2), progesterone (P) and testosterone (T) were determined for different types of polymer-based spherical activated carbon (PBSAC). Higher than 90% removal and significantly faster kinetics compared to conventional granular activated carbon (GAC) were observed, while performance was comparable with powdered activated carbon (PAC). No influence of pH in the range 2-12 was determined, while the presence of humic acid (HA) reduced both the removal and the kinetic by up to 20%.

View Article and Find Full Text PDF

Ferulic acid (FA) and tocopherol (Toc) loaded solid lipid nanoparticles (SLN) were prepared by a hot homogenisation method. The particle size distribution, zeta potential and melting behaviour of the SLN as well as the stability, encapsulation efficiency and radical scavenging activity of FA and Toc in the SLN were analysed. The different formulations containing up to 2.

View Article and Find Full Text PDF

We have studied the magnetic properties of the SURMOF-2 series of metal-organic frameworks (MOFs). Contrary to bulk MOF-2 crystals, where Cu(2+) ions form paddlewheels and are antiferromagnetically coupled, in this case the Cu(2+) ions are connected via carboxylate groups in a zipper-like fashion. This unusual coupling of the spin 1/2 ions within the resulting one-dimensional chains is found to stabilize a low-temperature, ferromagnetic (FM) phase.

View Article and Find Full Text PDF