Bringing down the cost of fuel cells: New catalyst dramatically cheaper without sacrificing performance

June 22, 2012
Zhen (Jason) He, assistant professor of civil engineering (left), and Junhong Chen, professor of mechanical engineering, display a strip of carbon that contains the novel nanorod catalyst material they developed for microbial fuel cells. Credit: Troye Fox

Engineers at the University of Wisconsin-Milwaukee (UWM) have identified a catalyst that provides the same level of efficiency in microbial fuel cells (MFCs) as the currently used platinum catalyst, but at 5% of the cost.

Since more than 60% of the investment in making is the cost of , the discovery may lead to much more affordable and .

The material – nitrogen-enriched iron-carbon nanorods – also has the potential to replace the used in hydrogen-producing microbial electrolysis cells (MECs), which use to generate a possible alternative to fossil fuels.

"Fuel cells are capable of directly converting fuel into electricity," says UWM Professor Junhong Chen, who created the nanorods and is testing them with Assistant Professor Zhen (Jason) He. "With fuel cells, electrical power from renewable energy sources can be delivered where and when required, cleanly, efficiently and sustainably."

The scientists also found that the nanorod outperformed a graphene-based alternative being developed elsewhere. In fact, the pair tested the material against two other contenders to replace platinum and found the nanorods' performance consistently superior over a six-month period.

The nanorods have been proved stable and are scalable, says Chen, but more investigation is needed to determine how easily they can be mass-produced. More study is also required to determine the exact interaction responsible for the nanorods' performance.

The work was published in March in the journal Advanced Materials ("Nitrogen-Enriched Core-Shell Structured Fe/Fe3C-C Nanorods as Advanced Catalysts for Oxygen Reduction Reaction").

The right recipe

MFCs generate electricity while removing organic contaminants from wastewater. On the anode electrode of an MFC, colonies of bacteria feed on organic matter, releasing electrons that create a current as they break down the waste.

On the cathode side, the most important reaction in MFCs is the oxygen reduction reaction (ORR). Platinum speeds this slow reaction, increasing of the cell, but it is expensive.

Microbial electrolysis cells (MECs) are related to MFCs. However, instead of electricity, MECs produce hydrogen. In addition to harnessing microorganisms at the anode, MECS also use decomposition of organic matter and platinum in a catalytic process at their cathodes.

Chen and He's nanorods incorporate the best characteristics of other reactive materials, with nitrogen attached to the surface of the carbon rod and a core of iron carbide. Nitrogen's effectiveness at improving the carbon catalyst is already well known. Iron carbide, also known for its catalytic capabilities, interacts with the carbon on the rod surface, providing "communication" with the core. Also, the material's unique structure is optimal for electron transport, which is necessary for ORR.

When the nanorods were tested for potential use in MECs, the material did a better job than the graphene-based catalyst material, but it was still not as efficient as platinum.

"But it shows that there could be more diverse applications for this material, compared to graphene," says He. "And it gave us clues for why the nanorods performed differently in MECs."

Explore further: Carbon Nanotubes Make Fuel Cells Cheaper

Related Stories

Carbon Nanotubes Make Fuel Cells Cheaper

February 9, 2009

( -- As fuel cells are becoming more popular due to their potential use in applications such as hydrogen-powered vehicles, auxiliary power systems, and electronic devices, the need for the precious metal platinum ...

Stainless Steel Catalyst Lowers Cost of Microbial Fuel Cells

February 23, 2009

( -- Tiny bacteria munching on and metabolizing biodegradable materials can produce electrons that could be harnessed by microbial fuel cells for energy. By taking advantage of the catalytic reactions of these ...

Cheap catalyst made easy

March 22, 2011

Catalysts made of carbon nanotubes dipped in a polymer solution equal the energy output and otherwise outperform platinum catalysts in fuel cells, a team of Case Western Reserve University engineers has found.

Recommended for you

A new form of real gold, almost as light as air

November 25, 2015

Researchers at ETH Zurich have created a new type of foam made of real gold. It is the lightest form ever produced of the precious metal: a thousand times lighter than its conventional form and yet it is nearly impossible ...

Getting under the skin of a medieval mystery

November 23, 2015

A simple PVC eraser has helped an international team of scientists led by bioarchaeologists at the University of York to resolve the mystery surrounding the tissue-thin parchment used by medieval scribes to produce the first ...

Moonlighting molecules: Finding new uses for old enzymes

November 27, 2015

A collaboration between the University of Cambridge and MedImmune, the global biologics research and development arm of AstraZeneca, has led researchers to identify a potentially significant new application for a well-known ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Jun 23, 2012
Right on. Platinum is so expensive and so rare that platinum-based fuel cells will always be too expensive for fuel cells to compete in the auto mass market.

I wish they had provided more details about this material, "nitrogen-enriched iron-carbon nanorods".

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.