Equipment built by German scientists can be used to study processes at interfaces with great accuracy. In an article published recently in ChemPhysChem, Hans Joachim Freund and co-workers of the Fritz-Haber-Institut in Berlin describe the advancement of four experimental techniques developed in their lab to investigate nanoscopic systems.
By combining photon scanning tunneling microscopy, aberration-corrected low-energy electron microscopy coupled to photoelectron emission microscopy, microcalorimetry, and electron-spin resonance spectroscopy, unique information on the relationship between geometric structure and properties is obtained. The methods can be applied to solve fundamental problems in surface science and to study interesting systems -particularly in the field of catalysis- which would otherwise be difficult (or impossible) to address.
“Catalysis happens at interfaces and experimental techniques are desperately needed to provide information on those systems”, says Freund who is interested in understanding disperse metal and oxide catalysts at the atomic scale. According to the researcher, appropriate samples in this field are very complex so that a combination of techniques is generally required to achieve a complete picture and avoid overestimating individual results. This led him and his colleagues to design new instruments to characterize their systems.
The first method developed by the German team could overcome one of the main disadvantages of scanning probe techniques, namely, their inherent chemical insensitivity, by detecting the fluorescence signal generated by locally exciting the surface with electrons from the tip. The new technique is called photon scanning tunneling microscopy (PSTM) and has been used to study the optical characteristics of metal particles and investigate defect structures in oxide surfaces. Additionally, the researchers are working on a new aberration-corrected instrument for low-energy electron microscopy (LEEM) and photoelectron emission microscopy (PEEM), which will hopefully allow them to investigate single supported nanocatalysts. Freund and co-workers have also built a highly sensitive microcalorimeter that can be used to measure temperature-dependent heats of adsorption on nanoparticle ensembles with aggregate sizes of about a hundred atoms. The fourth technique, called electron-spin resonance (ESR) spectroscopy, can be applied to study particle ensembles and may provide interesting information that is out of reach for other methods, the authors say.
Author: Hans Joachim Freund, Fritz-Haber Institut der Max-Planck Gesellschaft, Berlin (Germany), http://www.fhi-berlin.mpg.de/cp/hjf.epl
Title: Innovative Measurement Techniques in Surface Science
ChemPhysChem 2011, 12, No. 1, Permalink to the article: http://dx.doi.org/10.1002/cphc.201000812
Climate Impact Research in Hannover: Small Plants against Large Waves
17.08.2018 | Leibniz Universität Hannover
First transcription atlas of all wheat genes expands prospects for research and cultivation
17.08.2018 | Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung
New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference
Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.
Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...
17.08.2018 | Event News
08.08.2018 | Event News
27.07.2018 | Event News
17.08.2018 | Life Sciences
17.08.2018 | Event News
17.08.2018 | Materials Sciences