Scientists Develop Wonder Nanomaterial that Can Produce Energy, Clean Water and Hydrogen

 

by Mark Boyer, 03/24/13 Researchers in Singapore have developed a new nanomaterial that functions like the best Swiss army knife in the world. The material, known as Multi-use Titanium Dioxide (TiO2), can produce energy, it can generate hydrogen, and it can even produce clean water. But that’s not all: The remarkable material can also be formed into flexible solar cells and it can double the lifespan of lithium-ion batteries. And with bacteria-killing properties, it can also be used in new antibacterial bandages. The new material, which is being developed by scientists at Singapore’s Nanyang Technological University, is made by turning titanium dioxide crystals into nanofibers, which can then be formed into flexible filter membranes. The special material at the center of it all is titanium dioxide, which is cheap and abundant and has the ability to accelerate chemical reactions and can bond easily with water. Because it can bond with water, the material can potentially serve as a high-flux forward osmosis membrane and desalinate water. But that’s just one of its many remarkable features. In addition to producing clean water, the material can also produce hydrogen when exposed to sunlight, according to the researchers. And it can also be formed into an inexpensive, flexible solar cell that can be used to generate electricity. “While there is no single silver bullet to solving two of the world’s biggest challenges: cheap renewable energy and an abundant supply of clean water; our single multi-use membrane comes close, with its titanium dioxide nanoparticles being a key catalyst in discovering such solutions,” said lead researcher Darren Sun. “With our unique nanomaterial, we hope to be able to help convert today’s waste into tomorrow’s resources, such as clean water and energy.” + Nanyang Technological University Via PhysOrg

NIST ‘How-To’ Website Documents Procedures for Nano-EHS Research and Testing

 

From NIST Tech Beat: June 30, 2015 Contact: Michael Baum 301-975-2763 As engineered nanomaterials increasingly find their way into commercial products, researchers who study the potential environmental or health impacts of those materials face a growing challenge to accurately measure and characterize them. These challenges affect measurements of basic chemical and physical properties as well as toxicology assessments. To help nano-EHS (Environment, Health and Safety)researchers navigate the often complex measurement issues, the National Institute of Standards and Technology (NIST) has launched a new website devoted to NIST-developed (or co-developed) and validated laboratory protocols for nano-EHS studies. In common lab parlance, a "protocol" is a specific step-by-step procedure used to carry out a measurement or related activity, including all the chemicals and equipment required. Any peer-reviewed journal article reporting an experimental result has a "methods" section where the authors document their measurement protocol, but those descriptions are necessarily brief and condensed, and may lack validation of any sort. By comparison, on NIST's new Protocols for Nano-EHS website, the protocols are extraordinarily detailed. For ease of citation, they're published individually—each with its own unique digital object identifier (DOI). The protocols detail not only what you should do, but why and what could go wrong. The specificity is important, according to program director Debra Kaiser, because of the inherent difficulty of making reliable measurements of such small materials. "Often, if you do something seemingly trivial—use a different size pipette, for example—you get a different result. Our goal is to help people get data they can reproduce, data they can trust." A typical caution, for example, notes that if you're using an instrument that measures the size of nanoparticles in a solution by how they scatter light, it's important also to measure the transmission spectrum of the particles if they're colored, because if they happen to absorb light strongly at the same frequency as your instrument, the result may be biased. "These measurements are difficult because of the small size involved," explains Kaiser. "Very few new instruments have been developed for this. People are adapting existing instruments and methods for the job, but often those instruments are being operated close to their limits and the methods were developed for chemicals or bulk materials and not for nanomaterials." "For example, NIST offers a reference material for measuring the size of gold nanoparticles in solution, and we report six different sizes depending on the instrument you use. We do it that way because different instruments sense different aspects of a nanoparticle's dimensions. An electron microscope is telling you something different than a dynamic light scattering instrument, and the researcher needs to understand that." The nano-EHS protocols offered by the NIST site, Kaiser says, could form the basis for consensus-based, formal test methods such as those published by ASTM and ISO. NIST's nano-EHS protocol site currently lists 12 different protocols in three categories: sample preparation, physico-chemical measurements and toxicological measurements. More protocols will be added as they are validated and documented. Suggestions for additional protocols are welcome at nanoprotocols@nist.gov.

‘No-ink’ color printing achieved on nanomaterials

 

Tue, 06/09/2015 - 11:45am Andrew Careaga, Missouri University of Science and Technology   Missouri S&T researchers have developed a method to accurately print high-resolution images on nanoscale materials. They used the Missouri S&T athletic logo to demonstrate the process. At top left is the original logo. At right are examples of the logo printed at the nanoscale level.Researchers at Missouri University of Science and Technology are giving new meaning to the term “read the fine print” with their demonstration of a color printing process using nanomaterials. In this case, the print features are very fine—visible only with the aid of a high-powered electron microscope. The researchers describe their “no-ink” printing method in the latest issue of the journal Scientific Reports and illustrate their technique by reproducing the Missouri S&T athletic logo on a nanometer-scale surface. A nanometer is one billionth of a meter, and some nanomaterials are only a few atoms in size. The method described in the Scientific Reports article “Structural color printing based on plasmonic metasurfaces of perfect light absorption” involves the use of thin sandwiches of nanometer-scale metal-dielectric materials known as metamaterials that interact with light in ways not seen in nature. Experimenting with the interplay of white light on sandwich-like structures, or plasmonic interfaces, the researchers developed what they call “a simple but efficient structural color printing platform” at the nanometer-scale level. They believe the process holds promise for future applications, including nanoscale visual arts, security marking and information storage. The researchers’ printing surface consists of a sandwich-like structure made up of two thin films of silver separated by a “spacer” film of silica. The top layer of silver film is 25 nanometers thick and is punctured with tiny holes created by a microfabrication process known as focused ion beam milling. The bottom layer of silver is four times thicker than the top layer but still minuscule at 100 nanometers. Between the top and bottom films lies a 45-nanometer silica dielectric spacer. The researchers created a scaled-down template of the athletic logo and drilled out tiny perforations on the top layer of the metamaterial structure. Under a scanning electron microscope, the template looks like a needlepoint pattern of the logo. The researchers then beamed light through the holes to create the logo using no ink—only the interaction of the materials and light. By adjusting the hole size of the top layer, light at the desired frequency was beamed into the material with a perfect absorption. This allowed researchers to create different colors in the reflected light and thereby accurately reproduce the S&T athletic logo with nanoscale color palettes. The researchers further adjusted the holes to alter the logo’s official green and gold color scheme to introduce four new colors (an orange ampersand, magenta “S” and “T,” cyan pickaxe symbol and navy blue “Missouri”). “To reproduce a colorful artwork with our nanoscale color palettes, we replaced different areas in the original image with different nanostructures with specified hole sizes to represent various visible colors,” says Dr. Xiaodong Yang, an assistant professor at Missouri S&T, who leads the Nanoscale Optics Laboratory in the university’s mechanical and aerospace engineering department. “We chose the athletic logo to fill that need.” “Unlike the printing process of an inkjet or laserjet printer, where mixed color pigments are used, there is no color ink used in our structural printing process—only different hole sizes on a thin metallic layer,” says Dr. Jie Gao, an assistant professor of mechanical and aerospace engineering at Missouri S&T and a co-author of the paper. In their paper, the authors note that the process resulted in “pure colors with high brightness” with little need for protective coatings. The researchers believe the process could lead to “high-performance, pigment-free color printing and relevant applications such as security marking and information storage.” Other co-authors of the Scientific Reports paper are Dr. Fei Cheng, a researcher at Missouri S&T’s Nanoscale Optics Laboratory, and Dr. Ting S. Luk of the Center for Integrated Nanotechnologies at Sandia National Laboratories in Albuquerque, New Mexico. SOURCE: Missouri University of Science and Technology