A5082994244- Catalytic Processes in Materials Science
- Electron and X-Ray Spectroscopy Techniques
- Nanowire Synthesis and Applications
- Advanced Electron Microscopy Techniques and Applications
- Catalysis and Oxidation Reactions
- Graphene research and applications
- Electrocatalysts for Energy Conversion
- Advanced Materials Characterization Techniques
- Electronic and Structural Properties of Oxides
- Semiconductor Quantum Structures and Devices
- Catalysts for Methane Reforming
- nanoparticles nucleation surface interactions
- Carbon Nanotubes in Composites
- Semiconductor materials and devices
- Gold and Silver Nanoparticles Synthesis and Applications
- Surface and Thin Film Phenomena
- Semiconductor materials and interfaces
- Catalysis and Hydrodesulfurization Studies
- Advancements in Semiconductor Devices and Circuit Design
- Advancements in Solid Oxide Fuel Cells
- Copper-based nanomaterials and applications
- Anodic Oxide Films and Nanostructures
- Quantum Dots Synthesis And Properties
- Machine Learning in Materials Science
- ZnO doping and properties
Technical University of Denmark
2015-2024
University of Petroleum
2024
Danish Geotechnical Society
2014-2019
Australian National Fabrication Facility
2019
National Research Centre for the Working Environment
2019
Ørsted (Denmark)
2003-2017
Lund University
2006-2014
Karlsruhe Institute of Technology
2013
University of Copenhagen
2001-2009
Chemical Synthesis Lab
2006-2008
In situ transmission electron microscopy is used to obtain atom-resolved images of copper nanocrystals on different supports. These are catalysts for methanol synthesis and hydrocarbon conversion processes fuel cells. The undergo dynamic reversible shape changes in response the gaseous environment. For zinc oxide-supported samples, caused both by adsorbate-induced surface energies interfacial energy. supported silica, support has negligible influence structure. Nanoparticle dynamics must be...
Insight into the location, state, and function of a promoter in heterogeneous catalysis was obtained through atomic-resolution situ transmission electron microscopy. In most active ruthenium catalyst for ammonia synthesis known so far, barium is shown to be located two different phases catalyst. The increased activity suggested related two-dimensional barium-oxygen overlayer on crystals. possibility conducting such studies other reactions could add substantially our current understanding...
We have developed a technique so that both transmission electron microscopy and microphotoluminescence can be performed on the same semiconductor nanowire over large range of optical power, thus allowing us to directly correlate structural properties rotationally twinned zinc blende InP nanowires. constructed energy band diagram resulting multiquantum well heterostructure detailed quantum mechanical calculations hole wave functions. The excitation power dependent blue-shift photoluminescence...
Rotation during reaction Determining changes in heterogeneous catalysts under conditions can provide insight into mechanisms. Under conditions, not only metal nanoparticles change shape but their interaction with the oxide support could also be affected. Yuan et al. used aberration-corrected environmental transmission electron microscopy to study gold on titanium surfaces at low beam doses. During carbon monoxide (CO) oxidation total pressures of a few millibars and 500°C, they observed that...
Global warming caused by burning of fossil fuels is indisputably one mankind's greatest challenges in the 21st century. To reduce ever-increasing CO2 emissions released into atmosphere, dry solid adsorbents with large surface-to-volume ratio such as carbonaceous materials, zeolites, and metal-organic frameworks have emerged promising material candidates for capturing . However, remain because limited /N2 selectivity long-term stability. The effective adsorption gas (≈12 mol kg-1 ) on...
Efficient adhesion of gold thin films on dielectric or semiconductor substrates is essential in applications and research within plasmonics, metamaterials, 2D materials, nanoelectronics. As a consequence the relentless downscaling nanoscience technology, thicknesses layer overlayer have reached tens nanometers, it unclear if our current understanding sufficient. In this report, we investigated how Cr Ti layers influence nanostructure 2-20 nm Au by means high-resolution electron microscopy,...
Using a combination of complementary in situ X-ray photoelectron spectroscopy and diffraction, we study the fundamental mechanisms underlying chemical vapor deposition (CVD) hexagonal boron nitride (h-BN) on polycrystalline Cu. The nucleation growth h-BN layers is found to occur isothermally, i.e., at constant elevated temperature, Cu surface during exposure borazine. A lattice expansion borazine B precipitation from upon cooling highlight that incorporated into bulk, not just...
Imaging reactive surface water Recent developments in transmission electron microscopy (TEM) have enabled imaging of single atoms, but adsorbed gas molecules proven more challenging because a lack sufficient image contrast. Yuan et al. and carbon monoxide (CO) on reconstructed nanocrystalline anatase titanium dioxide (TiO 2 ) that has protruding TiO 3 ridges every four unit cells, which provide regions distinct Water adsorption this during environmental TEM experiments led to the formation...
Abstract Tuning and tailoring of surface terminating functional species hold the key to unlock unprecedented properties for a wide range applications largest 2D family known as MXenes. However, few routes are explored little is about extent which can saturate MXene surfaces. Among available terminations, atomic oxygen interest electrochemical energy storage, hydrogen evolution reaction, photocatalysis, etc. controlled oxidation surfaces not trivial due favored formation oxides. In present...
We report on magnetotransport measurements InSb nanowire quantum dots. The show that the levels of dots have giant g factors, with absolute values up to ∼70, largest value ever reported for semiconductor also observe these factors are level dependent and can differ strongly between different levels. presence indicates considerable contributions from orbital motion electrons preserved in measured dots, while level-to-level fluctuations arise spin−orbit interaction. deduced a ΔSO = 280 μeV...
Controlling chirality in growth of single-walled carbon nanotubes (SWNTs) is important for exploiting their practical applications. For long it has been conceptually conceived that the structural control SWNTs potentially achievable by fabricating nanoparticle catalysts with proper structures on crystalline substrates via epitaxial techniques. Here, we have accomplished formation monometallic Co nanoparticles well-defined crystal structure and its use as a catalyst selective SWNTs. Dynamics...
The strain distribution in heterostructured wurtzite InAs/InP nanowires is measured by a peak finding technique using high resolution transmission electron microscopy images. We find that with diameter of about 20 nm show 10 strained area over the interface and rest wire has relaxed lattice structure. parameters elastic properties for structure InAs InP are calculated nanowire simulated finite element calculations. Both method experimental results validated combination calculations image simulations.
Growth and structural analysis of epitaxial InAs/InSb nanowire heterostructures are demonstrated for the first time. InSb segments found to be perfect crystals, free stacking faults or other major defects, have a sharp interface with InAs (see image). After growth seed particle is single crystal nearly lattice matched nanowire. n-type form ohmic contacts Ni/Au electrodes.
A nanodispersed intermetallic GaPd2/SiO2 catalyst is prepared by simple impregnation of industrially relevant high-surface-area SiO2 with Pd and Ga nitrates, followed drying, calcination, reduction in hydrogen. The tested for CO2 hydrogenation to methanol at ambient pressure, revealing that the intrinsic activity higher than conventional Cu/ZnO/Al2O3, while production undesired CO lower. combination complementary situ ex techniques are used investigate catalyst. In X-ray diffraction extended...
Abstract This review highlights the importance of developing multi‐scale characterisation techniques for analysing operating catalysts in their working environment. We emphasise that a hierarchy situ provides macro‐, meso‐ and nano‐scale information is required to elucidate optimise catalyst performance fully. combined methodology should ideally embrace spatially resolved spatio‐temporal monitoring a) structure, catalytic activity, temperature heat/mass transfer pattern axial radial...
Preventing sintering of supported nanocatalysts is an important issue in nanocatalysis. A feasible way to choose a suitable support. However, whether the metal-support interactions promote or prevent has not been fully identified. Now, completely different behaviors Au nanoparticles on distinct anatase TiO2 surfaces have determined by situ TEM. The full processes were visualized (101) surface, which coupled Ostwald ripening and particle migration coalescence. In contrast, no (001) surface...
Mixing different elements at the nanoscale to obtain alloy nanostructures with fine-tuned physical and chemical properties offers appealing opportunities for nanotechnology nanoscience. However, despite widespread successful application of nanoparticles made by colloidal synthesis in heterogeneous catalysis, nanoalloy systems have been used very rarely solid-state devices nanoplasmonics-related applications. One reason is that such applications require integration arrays on a surface...
The recent market introduction of hydrogen fuel cell cars and the prospect a economy have drastically accelerated need for safe accurate detection hydrogen. In this Letter, we investigate use arrays nanofabricated Pd–Au alloy nanoparticles as plasmonic optical sensors. By increasing amount Au in up to 25 atom %, are able suppress hysteresis between absorption desorption, thereby sensor accuracy below 5% throughout investigated 1 mbar bar pressure range. Furthermore, observe an 8-fold...
Hydrogen sensors are a prerequisite for the implementation of hydrogen economy due to high flammability hydrogen-air mixtures. They comply with increasingly stringent requirements set by stakeholders, such as automotive industry and manufacturers safety systems, where sensor deactivation is severe but widely unaddressed problem. In response, we report intrinsically deactivation-resistant nanoplasmonic enabled rationally designed ternary PdAuCu alloy nanomaterial, which combines identified...
Abstract Recording atomic‐resolution transmission electron microscopy (TEM) images is becoming increasingly routine. A new bottleneck then analyzing this information, which often involves time‐consuming manual structural identification. deep learning‐based algorithm for recognition of the local structure in TEM was developed, stable to microscope parameters and noise. The neural network trained entirely from simulation but capable making reliable predictions on experimental images. method...