SI
SI
discoversearch

We've detected that you're using an ad content blocking browser plug-in or feature. Ads provide a critical source of revenue to the continued operation of Silicon Investor.  We ask that you disable ad blocking while on Silicon Investor in the best interests of our community.  If you are not using an ad blocker but are still receiving this message, make sure your browser's tracking protection is set to the 'standard' level.
Gold/Mining/Energy : Platinum Group Metals (PGMs) -- Ignore unavailable to you. Want to Upgrade?


To: aknahow who wrote (523)9/22/2012 7:30:54 PM
From: aknahow  Respond to of 529
 




















Nanotechnology in Fuel Cells
July 28th, 2012 nanoguru
Fuel cells are the next generation power source of electric vehicles. Typically, fuel cell is a device which converts a fuel directly into electricity in an electrochemical reaction. The fuel cells are electrochemical devices that combines hydrogen and oxygen to produce electricity, with water and heat as its by-product. A fuel cell consists of two electrodes, an anode and a cathode, with an electrolyte between them. The research in the field of fuel cells have thrown light in to the new ways to revolutionize transportation using fuel cells. The electric motors in this fuel cell vehicles will be powered by highly efficient fuel cells.

As the fuel cells are the next generation power sources, the research in this field is also getting much attention. The problem with the existing fuel cells are it contain membranes that allow hydrogen ions to pass through the cell but do not allow other atoms or ions. So, for this purpose membranes with better characteristics to be needed. Now researchers are using nanotechnology to create more efficient membranes; the new membrane will allow them to build longer lasting and lighter weight fuel cells.

The common catalysts used in fuels are hydrogen or methanol, to produce hydrogen ions. Platinum, a most expensive material is used as a catalyst in this process. As the platinum is an expensive material, a more economical material is needed to reduce the cost of fuel cells. The Research will lead to the replacement of nanoparticles of platinum as a catalyst to reduce the amount of platinum needed. The experiment is underway to use nanoparticles of other materials to replace platinum entirely and thereby lowering the cost of production. The catalytic electrodes in fuel cells has been replaced with platinum nanoparticles instead of a solid platinum surface. This will increases the efficiency, and allows much less platinum metal to be used.

For the case of transportation applications, the proton exchange membrane (PEM) fuel cells (also known as polymer electrolyte membrane fuel cells) are using. These fuel cells are powered by the electrochemical oxidation reaction of hydrogen and by the electro reduction of the oxygen contained in air.

Nanotechnology offers cheap bipolar materials using Nano composites, more efficient and less cost, non-platinum electro catalysts. The more thermally stable and more durable membranes to become available in the near future.

Another important invention this field is the use of carbon nanotubes. Modified carbon nanotubes can be used to replace platinum in fuel cells. By doping carbon nanotubes with nitrogen, or coating them in an electron-withdrawing polymer (polydiallyldimethylammonium chloride, or PDDA), the electronic properties of the nanotubes can be altered so as to make them effective as a catalyst and the electro catalytic activity of these modified nanotubes is found to be superior to that of platinum.

Now the problems with the fuels using in the fuel cell. At this time, commercial fuel cells can only run on a limited range of fuels. Most of the fuel cells using hydrogen, and some fuel cells are able to use methanol or natural gas. Further researcher in this field brings the fuel cells, highly efficient, portable and powerful power source. You can find different companies working in the field of fuel cells from understanding nano and comparison of fuel cells type is available in Wikipedia.

What you think about the future of fuel cells? Can it satisfy our need for highly efficient, portable power source for electric vehicles?



To: aknahow who wrote (523)9/22/2012 7:52:46 PM
From: aknahow  Respond to of 529
 


With nanotechnology rapidly advancing, the sci-fi dream of a Star Trek replicator becomes increasingly less fantastic. But such radical technology would, in theory, require the kind of subatomic manipulation that far exceeds current capabilities. Scientists lack both the equipment and the fundamental knowledge of quantum mechanics (the Standard Model, for all its elegance, remains incomplete) to build items from the raw stuff of quarks, gluons, and electrons . . . but what about alchemy?



Even Isaac Newton, credited with the dawn of the Age of Reason, felt the mystical draw of alchemy, working in secret to transform one element into another. Centuries later we still can’t conjure gold from lead, sure, but what if it was possible to combine a handful of elements to very closely mimic gold? What if scientists engineered a synthetic Midas Touch that tricked base metals into performing like gold, thereby conquering the hurdles of rarity and price?

Now forget the alchemist’s dream of gold and consider the equally precious noble metal platinum – hovering right around $50,000 per kilogram – which may be the key to building a sustainable energy future. Now, using advanced technology and elements that cost 1000 times less, researchers at Brookhaven National Lab have created a high-performing pauper’s platinum from nanoscale building blocks.

Beyond the silver sheen of the metal, platinum sets the gold standard (forgive the pun) for catalytic performance, improving a reaction’s efficiency while remaining largely unchanged. The electrolysis of water, or splitting H2O into oxygen (O2) and hydrogen (H2), requires external electricity and an efficient catalyst to break chemical bonds while shifting around protons and electrons. Once isolated, hydrogen gas offers one of the most promising renewable alternatives to dependence on a limited fossil fuel supply.

For a catalyst to facilitate an efficient reaction, it must combine high durability, high catalytic activity, and high surface area. Platinum knocks this out of the park, but its price discourages heavy investment from industry. The challenge, then, is to find what one Brookhaven chemist called a “Goldilocks” compound – the performance of platinum and the abundance of affordable non-noble metals.


This magnified image from a transmission electron microscope reveals the nanosheet structure of the breakthrough electrocatalyst, seen here as dark, straight lines.

The Brookhaven team first combined nickel ($20 per kilogram) and molybdenum ($32 per kilogram), and then used high-temperature ammonia to infuse the compound with bolstering nitrogen. Then something unexpected happened.

The scientists expected discrete, sphere-like particles, but the resulting low-cost compound, NiMoN, took the surprising form of two-dimensional (atom-thin) nanosheets. The catalytic activity then exceeded expectations, in part because of that huge boost in surface area – just consider the difference between a bed sheet balled up and one laid out flat. Their results were published online this week in Angewandte Chemie International Edition.

This electrocatalyst does not address all of the barriers to developing a hydrogen-based energy economy. The electricity required to perform water-splitting remains high and, right now, impractically expensive. But overcoming the high price and limited supply of platinum makes hydrogen more attractive than ever as a renewable fuel source. It also marks a major victory for the almost alchemical transformations possible in nanoscience.

Learn more about this new nanosheet compound in the official press release: Nanosheet Catalyst Discovered to Sustainably Split Hydrogen from Water



This post was written by Brookhaven Lab science writer Justin Eure.





To: aknahow who wrote (523)9/22/2012 8:10:48 PM
From: aknahow  Respond to of 529
 
An impending platinum crisis and its implications ... - Duke University
www.duke.edu/~cy42/Pt.pdf
You +1'd this publicly. Undo
File Format: PDF/Adobe Acrobat - Quick View
by CJ Yang - 2009 - Cited by 25 - Related articles
Feb 26, 2009 – In most cases, the only feasible substitutes for platinum are other PGMs, including palladium, rhodium, ruthenium, iridium, or osmium, but these ...



To: aknahow who wrote (523)9/22/2012 10:22:16 PM
From: aknahow  Read Replies (1) | Respond to of 529
 
University of Wisconsin-Milwaukee (UWM) researchers have identified an inexpensive nanorod catalyst with efficiencies rivaling that of platinum. Composed of nitrogen-enriched iron-carbon nanorods, the new catalyst holds the promise of cheaper, more efficient microbial fuel cells (MFCs) that generate their own hydrogen from waste water.

The hydrogen fuel cell is the holy grail of green energy. It burns hydrogen and gives off nothing but water. What could be more environmentally friendly than that? The problem is, hydrogen isn’t just lying about in the ground like oil or natural gas. True, it’s the most abundant element in the universe, but on Earth all of it is locked up in water and other chemicals. To be used as an energy source, the hydrogen has to be extracted and, unfortunately, the main source of most commercial hydrogen today comes from fossil fuels – which sort of defeats the purpose.

One alternative is microbial fuel cells, which use microorganisms to break down waste water into hydrogen and oxygen. That’s a step in the right direction, but there’s still a snag. To reach practical efficiency, an MFC needs a catalyst to goose along one of the chemical reactions involved in the process. That catalyst is usually platinum, which does its job very well, but is also extremely expensive at over US$1,200 per ounce. It also doesn’t help that platinum, like many catalysts, is susceptible to poisoning by impurities coating its surface, resulting in a very pricey replacement job.

In contrast, the UWM nanorod catalyst is composed of cheap, common elements. It consists of nitrogen bonded to the surface of a carbon rod with a core of iron carbide. According to the UWM researchers, this structure is optimal for electron transport. The upshot is that over three months of testing, the new catalyst demonstrated consistent performance that was superior to platinum and has every indication of being stable and scalable. More importantly, it’s much more economical. Platinum makes up 60 percent of the cost of an MFC and with the UMW catalyst only five percent the cost of a platinum catalyst, the savings are obvious.

According to nanorod creator Professor Junhong Chen,“fuel cells are capable of directly converting fuel into electricity. With fuel cells, electrical power from renewable energy sources can be delivered where and when required, cleanly, efficiently and sustainably.” With a view toward making the UMW catalyst practical, Professor Chen and his team are now concentrating on studying the exact characteristics of the catalyst and making it suitable for mass production.

Source: UWM