Microbial electrolysis cells (MECs) have been developed over the last few years as a way to produce hydrogen from food scraps and waste water. To put it very simply, the microbes feed on the waste and with the help of electricity and a catalyst, hydrogen is made. So far, expensive platinum has been used as the catalyst in this process, which has been effective, but the cost has held the technology back. Now researchers at Penn State have found a cheap substitute: stainless steel.

A piece of stainless steel works as a catalyst, but is only one-third as effective as the platinum, but researchers found that arranging the stainless steel in the form of a high-density bristle brush upped the hydrogen production to match and even exceed that of the platinum. The best part is that while the platinum part costs 15 cents, the stainless steel brush only costs 3 cents.

The researchers are still experimenting to find the best types and arrangements of stainless steel to maximize the hydrogen production, and even once those things are figured out, scientists will still have to discover a way to scale up this technology to be commercially viable. It seems daunting, but decreasing the cost will go a long way in allowing further progress.

via MIT Technology Review

One of the more expensive parts of a standard fuel cell is its platinum catalyst. Platinum is a metal that is good at splitting up the oxygen (O2) molecule into two oxygen ions (O+) at the cell’s cathode. Platinum is also pretty expensive. In a fuel cell for a typical passenger car, the platinum catalyst can cost about $4,000.

Researchers at the University of Dayton, however, have been able to use an array of carbon nanotubes to perform the same catalytic activity. The carbon nanotubes are doped with nitrogen (the full name is nitrogen-containing carbon nanotubes, or VA-NCNTs) – this is to prevent the carbon from reacting with oxygen to form CO, a process called “poisoning”. The CO builds up on the surface, and reduces the effectiveness of the catalyst over time. But these VA-NCNTs keep carbon unreactive, and thereby prolong the catalyst’s lifetime.

There’s no estimate yet on how much such a fuel cell would cost – no one has built a full prototype. There will certainly be costs involved in processing such precise and aligned nanotubes, but such costs would also certainly go down with economies of scale. The bottom line is that carbon is plentiful and cheap, while platinum is rare and expensive.

As fuel cells can be designed with fewer and fewer such rare metals and materials, the concept of a hydrogen economy gains more long-term credibility. Sure, some claim that hydrogen technology will always be 10 years away. But that statement is more a reflection of the practical hurdles that stand between us and a hydrogen economy, and less a reflection of technical flaws in the plan. That is, the hydrogen economy still looks really good on paper, and the replacement of platinum catalysts with carbon makes it look even better.

Via Green Car Congress