Hydrogen is one of the most promising fuels of the future. Whether powered by wind or sun energy, electrolysis of water is the method of choice for producing hydrogen without emission of carbon dioxide.
The character and properties of the hydrogen-producing catalyst, usually platinum, are of critical importance for the efficiency and cost of the electrocatalytic system. In the journal Angewandte Chemie, Jingguang G. Chen and a team at the University of Delaware (USA) have now introduced a new method for saving on platinum without losing efficiency: they deposit a single layer of platinum atoms onto an inexpensive tungsten carbide support.
Splitting water by electrolysis to produce hydrogen only works efficiently if the cathode, the cell’s negative electrode, is equipped with an efficient catalyst. Platinum is the material of choice because of its high activity—unfortunately it is very expensive, currently costing around 52 dollars a gram. “Its high price and limited availability are the biggest stumbling blocks on the way to the mass production of hydrogen through electrolysis,” explains Chen.
Current attempts to save on platinum by depositing platinum particles onto a support, have not been efficient enough. The platinum atoms often settle too far inside the porous support and are shielded from the reaction. Says Chen, “Our aim was to deposit a single layer of platinum atoms onto an inexpensive planar support so that all the platinum atoms can participate in the reaction.”
The problem with this method is that if such a monolayer of metal atoms is deposited onto a support, the atoms interact with the substrate. The electronic structure of the atoms can change because the distances between the individual atoms in the layer can be different from those in the pure metal. In addition, bonding between the platinum and atoms of the support can lead to undesired effects. This can greatly disrupt the catalytic properties.
Chen and his team selected tungsten carbide as a carrier. This inexpensive material has properties very similar to those of platinum. They deposited thin films of tungsten carbide onto a tungsten substrate and added platinum atoms by vapor deposition. The chemical and electronic properties of these atomic platinum monolayers on tungsten carbide did not differ significantly from those of a block of pure platinum. The catalytic efficiency of the supported platinum monolayer is also correspondingly strong.
“Tungsten carbide is the ideal substrate for platinum,” says Chen. “It is possible to use significantly smaller amounts of platinum, which reduces the cost—possibly not just for water electrolysis, but also in other platinum-catalyzed processes.”
Author: Jingguang G. Chen, University of Delaware, Newark (USA), mailto:firstname.lastname@example.org
Title: Low-Cost Hydrogen-Evolution Catalysts Based on Monolayer Platinum on Tungsten Monocarbide Substrates
Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201004718
NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation
Pollen taxi for bacteria
18.07.2018 | Technische Universität München
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
18.07.2018 | Life Sciences
18.07.2018 | Materials Sciences
18.07.2018 | Health and Medicine