Fuel cells are on the cutting edge of future technologies and have the potential to reshape our energy future.

The newly discovered process may help address one of the most significant difficulties in developing efficient and affordable fuel cells - how to extend the life of the catalysts that make them work.

Fuel cells combine hydrogen and oxygen without combustion to form water and to produce direct current electric power. The process can be described as electrolysis in reverse.

Essentially, a fuel cell is an electrochemical energy conversion device like a battery. Fuel cells produce electricity via a chemical reaction, harnessing the chemical attraction between hydrogen and oxygen. The oxygen is taken from the air, and hydrogen fuel can come from water via electrolysis or from fossil fuels like gasoline or methanol. A catalyst pries hydrogen atoms apart into a positive ion and an electron. The positive ions pass through a membrane to bond with the oxygen; the electron travels around the membrane and through a circuit, generating an electrical current. On the other side of the membrane, the oxygen, hydrogen ions and electrons recombine to form water.

Fuel cells have been pursued as a source of power for transportation because of their high energy efficiency, their potential for fuel flexibility, and their extremely low emissions.

Fuel cells have potential for stationary and vehicular power applications; however, the commercial viability of fuel cells for power generation in stationary and transportation applications depends upon solving a number of manufacturing, cost, and durability problems.

An important problem facing today´s most promising fuel cell technologies is that the same hydrogen that feeds the reaction often contains high levels of carbon monoxide formed during the hydrogen production process. The carbon monoxide (CO) "poisons," or degrades, the expensive platinum catalysts that convert hydrogen into electricity within the fuel cell, leading to deterioration in efficiency over time and eventual replacement.

Mahajan´s process uses a metal catalyst, nitrogen, methanol, and water to convert nearly 100 percent of the CO in the hydrogen feed into carbon dioxide and additional hydrogen. The resulting hydrogen feed contains only a few parts per million of CO, which could greatly extend the life of the catalysts that make fuel cells work

"The commercial viability of fuel cells for power generation depends upon solving a number of manufacturing, cost, and durability issues," said Mahajan. "Finding a simple, inexpensive method of producing hydrogen that is essentially free of carbon monoxide would help address many of those issues."

Fuel cell researchers have tried to solve the CO-poisoning problem in several different ways. By adding metals like ruthenium or molybdenum to the platinum, scientists have been able to formulate more tolerant catalysts, but even these are poisoned by relatively low levels of CO (100 parts per million or higher).

A second option is to send the hydrogen through a second process to remove most of the CO before feeding it into the fuel cell. This process typically employs a high-temperature catalytic reaction, known as water-gas-shift, which, due to thermodynamic constraints, leaves unacceptable levels of CO in the finished product.

In Mahajan´s new process, a ruthenium trichloride or similar metal catalyst is mixed with a nitrogen complex to form a homogenous solution in a methanol and water mixture. The hydrogen feed containing CO is then introduced, and, at relatively low temperatures (between 80 and 150 degrees C), the catalyst reacts with the CO and water to convert nearly 100 percent of the CO into carbon dioxide and, as a side benefit, additional hydrogen. The resulting hydrogen feed contains only a few parts per million of CO and is at the correct temperature to be fed directly into a fuel cell. The process also minimizes the amount of waste produced during the reaction due to low temperature operation, high product selectivity, and high catalytic activity.

"It´s quite an economical reaction, and it happens very quickly, in just a few seconds," said mahajan, "The process works with impure hydrogen produced by any method, including coal and biomass, and can be easily scaled up for more substantial production."

Mahajan believes his new hydrogen production method will assist the commercialization of proton exchange membrane fuel cells, which are the most promising fuel cells for widespread transportation use because they operate at low temperatures, produce a fast transient response, and possess relatively high energy densities compared to other fuel cell technologies.

"This is a very beautiful example for educating students about the benefits of clean fuel technologies," said Mahajan, who holds a joint appointment at Brookhaven and Stony Brook University, "and that can help drive public acceptance of new technologies."

Fuel cells have the potential to make the U.S. an energy independent nation, transforming the economy from one based on imported fossil fuels to a “hydrogen economy” fueled by hydrogen generated with local renewable resources.

Although the first fuel cell prototype was made in England in 1838, the modern version of fuel cell technology was developed as part of the Apollo moon program. NASA has demonstrated the commercial viability of fuel cells by continuing to use them to power space flights. All of the major auto manufacturers have fuel cell vehicles under development and Honda and Toyota began leasing fuel cell cars on a small scale in 2003.

Mahajan is the Group Leader for Advanced Fuels Group, Energy Sciences & Technology Department at BNL. Mahajan earned a B.Sc (1973) from Punjab University and his Ph.D. from the University of British Columbia in 1979. His research interests include design and evaluation of catalytic materials for “Future Fuels.”

One of the ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy, BNL conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security.