Tag Archives: Structure-Induced Enhancement in Electrooxidation of Trimetallic FePtAu Nanoparticles

Gold in them thar fuel cells

There’s a lot of interest in fuel cells where I live due primarily to the existence of Ballard Power Systems, which was founded here in the province of British Columbia, Canada. Here’s what it says on the About Ballard page,

Ballard Power Systems, Inc. is a global leader in PEM (proton exchange membrane) fuel cell technology. We provide clean energy fuel cell products enabling optimized power systems for a range of applications. Ballard offers smarter solutions for a clean energy future.

We are actively putting fuel cells to work in high-value commercial uses every day. In fact, Ballard has designed and shipped close to 150 MW of hydrogen fuel cell technology to date.

In addition to Ballard, Canada’s National Research Council located its Institute for Fuel Cell Innovation in Vancouver, British Columbia (after much lobbying from the province).

Despite all the excitement over the years (especially in the beginning), the fuel cell industry in British Columbia has yet to become the revenue producer that was promised.

According to some observers, one of the keys issues has been the metals used as catalysts and once the situation is resolved, fuel cells will come into their own. Researchers at Brown University have developed a nanoparticle that outperforms other metallic catalysts. From the March 12, 2012 news item on Nanowerk,

Advances in fuel-cell technology have been stymied by the inadequacy of metals studied as catalysts. The drawback to platinum, other than cost, is that it absorbs carbon monoxide in reactions involving fuel cells powered by organic materials like formic acid. A more recently tested metal, palladium, breaks down over time.

Now chemists at Brown University have created a triple-headed metallic nanoparticle that they say outperforms and outlasts all others at the anode end in formic-acid fuel-cell reactions. In a paper published in the Journal of the American Chemical Society (“Structure-Induced Enhancement in Electrooxidation of Trimetallic FePtAu Nanoparticles”), the researchers report a 4-nanometer iron-platinum-gold nanoparticle (FePtAu), with a tetragonal crystal structure, generates higher current per unit of mass than any other nanoparticle catalyst tested. Moreover, the trimetallic nanoparticle at Brown performs nearly as well after 13 hours as it did at the start. By contrast, another nanoparticle assembly tested under identical conditions lost nearly 90 percent of its performance in just one-quarter of the time.

The March 12, 2012 news release from Brown University describes how gold improves performance,

Gold plays key roles in the reaction. First, it acts as a community organizer of sorts, leading the iron and platinum atoms into neat, uniform layers within the nanoparticle. The gold atoms then exit the stage, binding to the outer surface of the nanoparticle assembly. Gold is effective at ordering the iron and platinum atoms because the gold atoms create extra space within the nanoparticle sphere at the outset. When the gold atoms diffuse from the space upon heating, they create more room for the iron and platinum atoms to assemble themselves. Gold creates the crystallization chemists want in the nanoparticle assembly at lower temperature.

Gold atoms create orderly places for iron and platinum atoms, then retreat to the periphery of the fuel cell, where they scrub carbon monoxide from fuel reactions. The tighter organization and cleaner reactions extend the cell's performance life. Credit: Sun Lab/Brown University

The researchers note that other metals may be substituted for gold as the best combinations are tested for combination and durability. (You can find more technical details in either the news item on Nanowerk or the news release at Brown University.)

Dexter Johnson at his Nanoclast blog (on the Institute of Electrical and Electronics Engineers [IEEE] website) provides a contrasting opinion as to why fuel cells have not become popular in his March 9, 2012 posting,

One of the fundamental problems with fuel cells has been the cost of producing hydrogen. While hydrogen is, of course, the most abundant element, it attaches itself to other elements like nitrogen or fluorine, and perhaps most ubiquitously to oxygen to create the water molecule. The process used to separate hydrogen out into hydrogen gas for powering fuel cells now relies on electricity produced from fossil fuels, negating some of the potential environmental benefits. So in the last few years, a new line of research has emerged that uses nanomaterials to imitate photosynthesis and break water down into hydrogen and oxygen thereby creating a more cost-effective and environmentally-friendly method for producing hydrogen.

If you’re interested, Dexter goes on to describe some promising areas of research that mimic photosynthesis.

In that odd area where coincidences meet, the latest work that Dexter discusses is taking place in California, a major centre for the gold rush of the 1800s. As it turns out, British Columbia was also a major destination in the days of the gold rush.