[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.]
Hybrid cellular nanosheets show promise as basis for high performance anodes for Li-ion batteries
September 14, 2015
Researchers in S. Korea have developed a simple synthetic method for producing carbon-based hybrid cellular nanosheets that exhibit strong electrochemical performance for many key aspects of high-performance lithium-ion battery anodes. The nanosheets consist of close-packed cubic cavity cells partitioned by carbon walls, resembling plant leaf tissue.
Loading the carbon cellular nanosheets with SnO2 nanoparticles as a model system, the team found that the resulting anode materials showed a specific capacity of 914 mAh g–1 on average with a retention of 97.0% during 300 cycles. When the cycling current density was increased from 200 to 3000 mA g–1, the reversible capacity was decreased by only 20% from 941.3 to 745.5 mAh g–1. A paper on their work is published in the Journal of the American Chemical Society.
Rice team demonstrates plasmonic hot-electron solar water-splitting technology; simpler, cheaper and efficient
September 05, 2015
Researchers at Rice have demonstrated an efficient new way to use solar energy for water splitting. The technology, described in a paper in the ACS journal Nano Letters, relies on a novel plasmonic photoelectrode architecture of light-activated gold nanoparticles that harvest sunlight to drive photocatalytic reactions by efficient, non-radiative plasmon decay into “hot carriers”—highly excited electrons.
In contrast to past work, the new architecture does not utilize a Schottky junction—the commonly used building block to collect hot carriers. Instead, the team observed large photocurrents from a Schottky-free junction due to direct hot electron injection from plasmonic gold nanoparticles into the reactant species upon plasmon decay.
Argonne researchers develop macroscale superlubricity system with help of Mira supercomputer; potential for “lubricant genome”
July 22, 2015
Argonne scientists have used the Mira supercomputer to identify and to improve a new mechanism for eliminating friction, which fed into the development of a hybrid material that exhibited superlubricity—a state in which friction essentially disappears—at the macroscale—i.e., at engineering scale—for the first time. A paper on their work was published in the journal Science.
They showed that superlubricity can be realized when graphene is used in combination with nanodiamond particles and diamond-like carbon (DLC). Simulations showed that sliding of the graphene patches around the tiny nanodiamond particles led to nanoscrolls with reduced contact area that slide easily against the amorphous diamond-like carbon surface, achieving incommensurate contact and a substantially reduced coefficient of friction (~0.004).
Penn and ExxonMobil researchers uncover mechanisms behind performance of major antiwear additive in lubricants
March 13, 2015
One of the main modern antiwear lubricant additives is zinc dialkyldithiophosphate (ZDDP)—widely used in automotive lubricants—which forms crucial antiwear tribofilms at sliding interfaces. However, despite its importance in prolonging machinery life and reducing energy use, the mechanisms governing its tribofilm growth are not well-understood. This limits the development of replacements with better performance and catalytic converter compatibility.
Now, in a study published in the journal Science, researchers from the University of Pennsylvania and ExxonMobil, have uncovered the mechanisms governing the growth of ZDDP antiwear tribofilms at sliding interfaces. The study provides a way forward for scientifically testing new anti-wear additives. Being able to pinpoint the level of stress at which they begin to break down and form tribofilms allows researchers to compare various properties in a more rigorous fashion.
Lintec licenses UTD carbon nanotube technology, opens center to spur commercialization
February 09, 2015
Lintec of America has licensed novel fabrication methods for carbon nanotube (CNT) macrostructures, including sheets, yarns and ribbons, developed at the University of Texas at Dallas (UTD) by Dr. Ray Baughman, the Robert A. Welch Distinguished Chair in Chemistry, and his colleagues at the University’s Alan G. MacDiarmid NanoTech Institute, which he directs.
Lintec has trademarked the technology as DryDraw and cSilk, and is forming the Nano-Science and Technology Center (NSTC) in Richardson, TX, to focus on scaling up the manufacturing and commercialization of nano-engineered applications.
Rice, Minnesota scientists use predictive modeling to identify optimized zeolites to aid ethanol, petroleum production
January 23, 2015
Scientists at Rice University and the University of Minnesota have identified, through a large-scale, multi-step computational screening process, promising zeolite structures for two energy-related applications: the purification of ethanol from fermentation broths and the hydroisomerization of alkanes with 18–30 carbon atoms encountered in petroleum refining.
The results, presented in a paper published in Nature Communications, demonstrate that predictive modeling of synthetic zeolites—a technique pioneered by Rice bioengineer Michael Deem—and data-driven science can be applied to solve some of the most challenging problems facing industries that require efficient ways to separate or catalyze materials.
Researchers develop free-standing nanowire mesh for direct solar water-splitting to produce H2; new design for “artificial leaf”
December 03, 2014
|The mesh with BiVO4 nanowire photoanode for water oxidation and Rh-SrTiO3 nanowire photocathode for water reduction produces hydrogen gas without an electron mediator. Credit: ACS, Liu et al. Click to enlarge.|
Researchers from UC Berkeley, Lawrence Berkeley National Laboratory and Nanyang Technological University, Singapore have developed a new technology for direct solar water-splitting—i.e., an “artificial leaf” to produce hydrogen—based on a nanowire mesh that lends itself to large-scale, low-cost production. A paper describing their work is published in the journal ACS Nano.
In the design, semiconductor photocatalysts are synthesized as one-dimensional nanowires, which are assembled into a free-standing, paper-like mesh using a vacuum filtration process from the paper industry. When immersed in water with visible light irradiation (λ ≥ 400 nm), the mesh produces hydrogen gas. Although boosting efficiency remains a challenge, their approach—unlike other artificial leaf systems—is free-standing and doesn’t require any additional wires or other external devices that would add to the environmental footprint.