[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.]
Ultrafine jagged Pt nanowires extremely efficient ORR catalysts; 50x more power than current commercial catalyst
November 18, 2016
An international team led by researchers at UCLA and Caltech has demonstrated that altering the form of platinum nanoscale wires from a smooth surface to a jagged one can significantly reduce the amount of precious metal required as a catalyst for the oxygen reduction reaction (ORR) in fuel cells and thus lower the cost. According to the findings, the newly developed catalyst is so active that the amount of platinum required for a fuel cell could be 1/50 of what is needed today.
In a paper published in Science, the team reports that the jagged Pt nanowires exhibit an ECSA (electrochemical active surface area) of 118 m2 per gram Pt and a specific activity of 11.5 mA per square centimeter for ORR for a mass activity of 13.6 ampere per milligram Pt, nearly doubling previously reported best values. Reactive molecular dynamics simulations suggested that the highly stressed, under-coordinated rhombohedral-rich surface configurations of the jagged nanowire enhanced ORR activity versus more relaxed surfaces.
CNT nanostiches strengthen laminated composites
August 03, 2016
A team from MIT and Saab AB has found a way to bond composite layers in such a way that the resulting material is substantially stronger and more resistant to damage than other advanced composites. Their results are published this week in the journal Composites Science and Technology.
The team reinforced aerospace-grade unidirectional carbon fiber laminate interfaces with high densities (>10 billion fibers per cm2) of aligned carbon nanotubes (A-CNTs) that act as nano-scale “stitches”. Such nano-scale fiber reinforcement of the ply interfaces has already been shown to increase interlaminar fracture toughness; the MIT researchers showed that laminate in-plane strengths are also increased via the technique.
Lawrence Livermore team shows carbon nanotube porins are fastest known proton conductors; potential application for PEM fuel cells
April 05, 2016
Lawrence Livermore National Laboratory (LLNL) researchers have shown that 0.8-nm-diameter carbon nanotube porins, which promote the formation of one-dimensional water wires, can support proton transport rates exceeding those of bulk water by an order of magnitude.
The transport rates in these nanotube pores also exceed those of biological channels and Nafion—one of the most common and commercially available membranes for proton exchange membrane (PEM fuel cells). Carbon nanotubes are the fastest known proton conductor. The research appears in the journal Nature Nanotechnology. Practical applications include proton exchange membranes (PEMs); proton-based signaling in biological systems; and the emerging field of proton bioelectronics (protonics).
NREL reveals thermoelectric potential for tailored semiconducting carbon nanotubes
A finely tuned carbon nanotube thin film has the potential to act as a thermoelectric power generator that captures and uses waste heat, according to researchers at the Energy Department’s National Renewable Energy Laboratory (NREL).
The research could help guide the manufacture of thermoelectric devices based on either single-walled carbon nanotube (SWCNT) films or composites containing these nanotubes. Because more than half of the energy consumed worldwide is rejected primarily as waste heat, the idea of thermoelectric power generation is emerging as an important part of renewable energy and energy-efficiency portfolios.
PNNL team develops higher-strength, lower-cost titanium alloy aimed at improving vehicle fuel economy and reducing CO2 emissions
April 02, 2016
An improved titanium alloy—stronger than any commercial titanium alloy currently on the market—gets its strength from the novel way atoms are arranged to form a special nanostructure. For the first time, a team led by researchers at Pacific Northwest National Laboratory (PNNL) have been able to see this alignment and then manipulate it to make the strongest titanium alloy (hierarchical nanostructured Ti-185, or HNS Ti-185) yet developed. On top of the gains in strength, the new alloy benefits from a lower cost process.
In an open access paper published in the journal Nature Communications, the researchers note that that material is an excellent candidate for producing lighter vehicle parts, and that this newfound understanding may lead to creation of other high strength alloys.
ORNL team gains insight into elastic properties of next-gen energy storage material MXene; understanding how ions flow
March 16, 2016
Researchers at Oak Ridge National Laboratory, with a colleague from Drexel University, have combined advanced in-situ microscopy and theoretical calculations to uncover important clues to the elastic properties of an MXene material—a promising next-generation energy storage material for supercapacitors and batteries—(earlier post), specifically a 2D titanium carbide (Ti3C2Tx).
MXene material—which acts as a two-dimensional electrode that could be fabricated with the flexibility of a sheet of paper—is based on MAX-phase ceramics (ternary carbides), discovered two decades ago by Michel Barsoum, PhD, Distinguished professor in Drexel’s Department of Materials Science & Engineering. Chemical removal of the “A” layer leaves two-dimensional flakes composed of transition metal layers—the “M”—sandwiching carbon or nitrogen layers (the “X”) in the resulting MXene, which physically resembles graphite.