In an attempt to understand why ruthenium sulfide (RuS2) is so good at removing sulfur impurities from fuels, scientists at the U.S. Department of Energys Brookhaven National Laboratory have succeeded in making a model of this catalyst -- nanoparticles supported on an inert surface -- which can be studied under laboratory conditions. "If we can understand why this catalyst is so active, we might be able to make it even better, or use what we learn to design other highly efficient catalysts," said Tanhong Cai, one of the scientists who made the model.
Removing sulfur from fossil fuels such as oil and coal is mandated because the resulting fuels burn more cleanly and efficiently. One common way of achieving this is to add hydrogen in the presence of a catalyst to release hydrogen sulfide (H2S). Recently, RuS2 was found to be 100 times more active than the catalyst most commonly used for this "hydrodesulfurization" reaction. But studying the catalyst in action is nearly impossible because the reaction takes place at high temperatures and under extreme pressure.
The Brookhaven team has therefore created a model of the catalyst via a chemical reaction that deposits nanosized particles of RuS2 on a nonreactive gold surface. The small size of the particles maximizes the surface area available for the catalytic reaction to take place, and makes it ideal for analysis by classic surface chemistry techniques, such as scanning tunneling microscopy and x-ray photoemission spectroscopy. The entire model is being studied under well-defined ultrahigh vacuum conditions.
Karen McNulty Walsh | EurekAlert!
Producing electricity during flight
20.09.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau
Solar-to-fuel system recycles CO2 to make ethanol and ethylene
19.09.2017 | DOE/Lawrence Berkeley National Laboratory
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
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