Catalyst Technology | Single Nano-Catalyst | Precious Metal Dispersion Model

In automobile catalytic converters, the surface conditions of the precious metals—the catalyst materials—have a large effect on their ability to clean emissions. Conventionally, precious metal particles are adhered to a base material. However, heat from the exhaust gas causes the particles to collect together and agglomerate to form larger particles. This reduces the surface area of the precious metals and deteriorates their performance as catalysts. To counter this effect, large amounts of precious metals must be used in conventional catalytic converters. As an alternative, Mazda takes advantage of single nanotechnology to realize a unique and new catalyst structure in which precious metal particles are individually embedded into the base material.

The new catalyst has two main features.
1. It inhibits the thermal deterioration caused by the agglomeration of precious metal particles
2. It offers a significant improvement in oxygen absorption and release rates for enhanced emissions cleaning
With these features, the amount of precious metals needed to ensure the same level of effectiveness is reduced by 70 to 90 percent compared to previous products. At the same time, the performance of the catalytic converter is almost unaffected by harsh driving styles.

This technology can significantly reduce the amounts of expensive precious metals such as platinum, palladium and rhodium needed for three-way catalysts to effectively clean exhaust emissions from gasoline engines.

Nano Composite Material

If someone does a lot of arm curls at the gym, the typical result is that the bones and muscles in their arms will get stronger. Recently, researchers at Houston’s Rice University inadvertently created a nano composite that behaves in the same way. Although the material doesn’t respond to static stress, repeated mechanical stress will cause it to become stiffer.

The discovery was made in the lab of Pulickel Ajayan, Rice University professor of mechanical engineering and materials science, and of chemistry. Graduate student Brent Carey had created a composite material by infiltrating a batch of vertically aligned, multi-walled nanotubes with Polydimethylsiloxane, which is an inert, rubbery polymer. He was testing the high-cycle fatigue properties of the composite, and was surprised to discover that instead of weakening when subjected to repeated loads, it actually got stronger.
Over the course of a week, the material was subjected to 3.5 million compressions. This caused its stiffness to increase by 12 percent, with indications that there was potential for further stiffening. The reason for this type of reaction is still something of a mystery.
"We were able to rule out further cross-linking in the polymer as an explanation," said Carey. "The data shows that there’s very little chemical interaction, if any, between the polymer and the nanotubes, and it seems that this fluid interface is evolving during stressing."
What is known is that the use of nanomaterials greatly increases the surface area available to that fluid interface, so whatever reaction is taking place is much more pronounced than would be the case with a conventional composite.
Carey is already envisioning potential uses for materials utilizing the process. "We can envision this response being attractive for developing artificial cartilage that can respond to the forces being applied to it but remains pliable in areas that are not being stressed," he stated.

New Nano Composite Processing Technique

A new technique for creating films of barium titanate (BaTiO3) nano particles in a polymer matrix could allow fabrication of improved capacitors able to store twice as much energy as conventional devices. The improved capacitors could be used in consumer devices such as cellular telephones – and in defense applications requiring both high energy storage and rapid current discharge.

This capacitor array device made with a barium titanate nanocomposite.

Because of its high dielectric properties, barium titanate has long been of interest for use in capacitors, but until recently materials scientists had been unable to produce good dispersion of the material within a polymer matrix. By using tailored organic phosphonic acids to encapsulate and modify the surface of the nano particles, researchers at the Georgia Institute of Technology’s Center for Organic Photonics and Electronics were able to overcome the particle dispersion problem to create uniform nano composites.

For capacitors and related applications, the amount of energy you can store in a material is related to these two factors.

1. High Dielectric Constant

2. High Dielectric breakdown Strength

The new nanocomposite materials have been tested at frequencies of up to one megahertz, and the research says operation at even higher frequencies may be possible. Though the new materials could have commercial application without further improvement, their most important contribution may be in demonstrating the new encapsulation technique – which could have broad applications in other nanocomposite materials.

This work opens a door to effectively exploit this type of particle in nano composites using the coating technology.

Because of their ability to store and rapidly discharge electrical energy, capacitors are used in a variety of consumer products such as computers and cellular telephones. And because of the increasing demands for electrical energy to power vehicles and new equipment, they also have important military applications.

Key to developing thin-film capacitor materials with higher energy storage capacity is the ability to uniformly disperse nano particles in as high a density as possible throughout the polymer matrix. However, nano particles such as barium titanate tend to form aggregates that reduce the ability of the nanocomposite to resist electrical breakdown. Other research groups have tried to address the dispersal issue with a variety of surface coatings, but those coatings tended to come off during processing – or to create materials compatibility issues.

The robust Designed coating for the particles, which range in size from 30 to 120 nanometers in diameter.

“Phosphonic acids bind very well to barium titanate and to other related metal oxides”. “The choice of that material and ligands were very effective in allowing us to take the tailored phosphonic acids, put them onto the barium titanate, and then with the correct solution processing, to incorporate them into polymer systems. This allowed us to provide good compatibility with the polymer hosts – and thus very good dispersion as evidenced by a three- to four-fold decrease in the average aggregate size.”

Though large crystals of barium titanate could also provide a high dielectric constant, they generally do not provide adequate resistance to breakdown – and their formation and growth can be complex and require high temperatures. Composites provide the necessary electrical properties, along with the advantages of solution-based processing techniques.

“One of the big benefits of using a polymer nanocomposite approach is that you combine particles of a material that provide desired properties in a matrix that has the benefits of easy processing,”.

Scanning electron micrographs of barium titanate (BaTiO3) nano composites with polycarbonate (left, top and bottom) and Viton (right, top and bottom) polymer matrices. The images show the dramatic improvement in film uniformity through the use of phosphonic acid coated BaTiO3 nano particles (bottom images) as compared to uncoated nano particles (top images). The higher uniformity results in greatly improved dielectric properties.

Though the new materials may already offer enough of an advantage to justify commercializing. The research team also wants to scale up production to make larger samples – now produced in two-inch by three-inch films – available to other researchers who may wish to develop additional applications.

“Beyond capacitors, there are many areas where high dielectric materials are important, such as field-effect transistors, displays and other electronic devices,” Perry added. “With our material, we can provide a high dielectric layer that can be incorporated into those types of applications.”

Portable Solar Power Plant, Water Purifier And Fuel Cell In One |

In many areas of the world, and also during times of natural disasters, clean drinking water and access to power are scarce.  The company The Essential Element has designed the Hydra water purifier and fuel cell to take care of both of those problems at once.

The Hydra is equipped with a 2.88 kW solar panel array that runs a pump that pushes water through a self-cleaning filtration device (capable of purifying 87,000 liters a day), juices up lead-acid gel batteries and runs an electrolyzer that splits some of that water to fill a .37 cubic-meter tank with pressurized hydrogen.

The fuel cell can be used to power communication devices or a camp stove.  The whole device can easily be set up and collapsed for easy transport and includes PV mats that can be plugged into the device for extra power.