[Due to the increasing size of the archives, each topic page now contains only the prior 365 days of content. Access to older stories is now solely through the Monthly Archive pages or the site search function.]
PowerDriver simulations predict thermoelectric exhaust waste heat recovery output of 300W, -2.5% in fuel consumption; prototyping begins
August 22, 2013
The European Union-funded PowerDriver project—a two-year, €3-million (US$4-million) research project initiated in February 2012 to turn exhaust gas waste heat into electricity using thermoelectric generator (TGEN) technology—has completed simulation work on on a potential automotive application. Results suggest TGEN output of 300W and equivalent fuel saving over the NEDC drive cycle of 2.5%
The PowerDriver project is a collaborative research initiative involving Jaguar Land Rover Ltd and Rolls-Royce PLC together with supply chain and research and development partners and universities. Jaguar Land Rover Ltd is interested in technology capable of being applied to gasoline engine passenger cars while Rolls-Royce PLC is interested in marine applications related to diesel engines.
ORNL finding on surface properties of complex oxides films could lead to better batteries and catalysts
August 14, 2013
Researchers at Oak Ridge National Laboratory (ORNL), with colleagues from the Chinese Academy of Sciences and Fudan University, have discovered that key surface properties of complex oxide films are unaffected by reduced levels of oxygen during fabrication—an unanticipated finding with possible implications for the design of functional complex oxides.
The discovery, which may result in better batteries, catalysts, electronic information storage and processing devices, is reported in a paper published in the RSC journal Nanoscale.
EPFL/Technion team develops “champion” nanostructures for efficient solar water-splitting to produce hydrogen
July 15, 2013
|Hydrogen bubbles as they appear in a photoelectrochemical cell. © LPI / EPFL. Click to enlarge.|
Researchers from EPFL in Switzerland and Technion-Israel Institue of Technology have developed nanoparticle-based α-Fe2O3 (hematite) electrodes that achieve the highest photocurrent of any metal oxide photoanode for photoelectrochemical water-splitting under 100 mW cm−2 air mass, 1.5 global sunlight. A paper on their work is published in the journal Nature Materials.
With current methods, in which a conventional photovoltaic cell is coupled to an electrolyzer to produce hydrogen, the cost to produce hydrogen from water using the sun is around €15 per kilo at its cheapest, said research leader Dr. Michael Grätzel, Director of the Laboratory of Photonics and Interfaces (LPI) at EPFL and inventor of dye-sensitized photoelectrochemical cells. “We’re aiming at a €5 charge per kilo,” he said.
Nickel phosphide nanoparticle shown to be efficient non-noble metal electrocatalyst for hydrogen production
June 17, 2013
In the electrochemical reduction of water to molecular hydrogen, the hydrogen evolution reaction (HER) is facilitated by noble metal catalysts such as platinum (Pt), which generate large cathodic current densities for this reaction at low overpotentials.
A research team led by Raymond Schaak, a professor of chemistry at Penn State University, now reports that nanoparticles of nickel phosphide (Ni2P)—the two component elements of which are inexpensive and earth-abundant—have demonstrated among the highest HER activity of any non-noble metal electrocatalyst reported to date. A paper on the work is published in the Journal of the American Chemical Society.
New MOF could enable more efficient and cost-effective production of high octane gasoline
May 24, 2013
An international team of researchers has developed a new metal-organic framework (MOF) that might provide a significantly improved method for separating hexane isomers in gasoline according to their degree of branching. A paper on the work is published in the journal Science.
Created in the laboratory of Jeffrey Long, professor of chemistry at the University of California, Berkeley, the MOF features triangular channels that selectively trap only the lower-octane hexane isomers based on their shape, separating them easily from the higher-octane molecules in a way that could prove far less expensive than the industry’s current method for producing high-octane fuel. The Long laboratory and UC Berkeley have applied for a patent on the MOF Fe2(bdp)3. (BDP2– = 1,4-benzenedipyrazolate)
MIT team devises approaches for practical carbon-nanotube-coated carbon fiber; stronger, more electrically conductive
May 20, 2013
|MIT scientists demonstrated two approaches for growing CNTs on carbon fiber without degrading the fiber strength. Credit: ACS, Steiner et al. Click to enlarge.|
Researchers at MIT have demonstrated two approaches for producing carbon fibers coated in carbon nanotubes without degrading the underlying fiber’s strength. A paper on the work, which could result in carbon-fiber composites that are not only stronger but also more electrically conductive, is published in the journal ACS Applied Materials & Interfaces.
Hierarchical carbon fibers (CFs) sheathed with radial arrays of carbon nanotubes (CNTs) are promising candidates for improving the intra- and interlaminar properties of advanced fiber-reinforced composites (such as graphite/epoxy) and for high-surface-area electrodes for battery and supercapacitor architectures, the authors note.
Researchers demonstrate water splitting to generate hydrogen using ultra-small Si nanoparticles
January 18, 2013
|Schematic showing CO2 laser pyrolysis synthesis of silicon nanoparticles transferred to a custom stainless steel prototype cartridge used to generate hydrogen for fuel cell applications. Credit: ACS, Erogbogbo et al. Click to enlarge.|
A team of researchers from the University at Buffalo (SUNY) have demonstrated that hydrogen generation from ultra-small silicon nanoparticles (10 nm diameter) proceeds much more rapidly than expected based upon extrapolation of rates obtained using larger particles. The ultra-small particles react with water to generate hydrogen 1,000 times faster than bulk silicon, 100 times faster than previously reported Si structures, and 6 times faster than competing metal formulations.
In a paper published in the ACS journal Nano Letters, they report that the hydrogen production rate using 10 nm Si is 150 times that obtained using 100 nm particles—significantly exceeding the expected effect of increased surface to volume ratio. These results imply that nanosilicon could provide a practical approach for on-demand hydrogen production without the addition of heat, light, or electrical energy, they suggested.
US/China research team proposes “solar energy funnel” to harness photons for electricity; using elastic strain to capture a wider spectrum
November 26, 2012
|A visualization of the broad-spectrum solar energy funnel. Image: Yan Liang. Click to enlarge.|
Researchers from Peking University in China and MIT are proposing using elastic strain as a viable agent to create an optoelectronic material with a spatially varying bandgap that is tunable for use in photovoltaics, photocatalysis and photodetection. In a paper published in Nature Photonics, they propose that a photovoltaic device made from a strain-engineered MoS2 monolayer will capture a broad range of the solar spectrum and concentrate excitons or charge carriers.
The “funnel” is a metaphor: electrons and their counterparts, holes—which are split off from atoms by the energy of photons—are driven to the center of the structure by electronic forces. However, the material actually does assume the shape of a funnel—a stretched sheet of thin material, nano-indented at its center by a microscopic needle that produces a curved, funnel-like shape.
IACT team using ALD to build nanobowls for tailored catalysts for biofuel production
October 27, 2012
A team of scientists from the Institute for Atom Efficient Chemical Transformations (IACT)—an Energy Frontier Research Center (earlier post) led by Argonne National Laboratory (ANL), and including Northwestern University, the University of Wisconsin and Purdue University—is using atomic layer deposition (ALD) to build nanoscale “bowls” that protect metal catalysts from the harsh conditions of biofuel refining.
In recent years, nanoparticles of metals such as platinum, iridium and palladium supported on metal oxide surfaces have been considered as catalysts to convert biomass into alternative fuels as efficiently as possible. Unfortunately, under typical biorefining conditions where liquid water may reach temperatures of 200 °C and pressures of 4,100 kilopascals (597 psi), the tiny metal nanoparticles can agglomerate into much larger particles which are not catalytically active. Additionally, these extreme conditions can dissolve the support.
XG Sciences lands SBIR/STTR award to develop Si/graphene anodes for Li-ion batteries for EVs
October 15, 2012
|Plot of current performance data in the lab for Si/graphene anodes. Source: XG Sciences. Click to enlarge.|
As part of the FY 2012 Phase I Release 3 SBIR/STTR Award program, the US Department of Energy (DOE) has awarded Michigan-based XG Sciences, a manufacturer of graphene nanoplatelets (earlier post), a contract to develop low-cost, high-energy Si/graphene anodes for Li-ion batteries for use in extended range electric vehicle applications. XG Sciences will lead a team that includes battery maker LG Chem Power, Inc. and the Georgia Institute of Technology.
XG Sciences’ Silicon-graphene nanocomposite anode materials have demonstrated significant increases in energy storage capacity over traditional graphite and are manufactured with a commercially-proven, low-cost process using widely-available and economical starting materials. Current performance data from the company shows demonstrated specific capacity of 900 – 2000 mAh/g, with a 1st cycle efficiency of 80+ %.