Scientists are trying to utilize efficient nanotechnology catalysts to power hydrogen fuel cells. Such materials include palladium and platinum. Fuel cells require catalysts that facilitate the reaction of hydrogen and oxygen. The reaction of hydrogen and oxygen produces electrical energy. The only byproduct from the reaction is liquid or vaporous water.

Scientists are exploring ways to power hydrogen fuel cells with a material called palladium that may prove useful in the near future. The palladium to be used will be in the form of nanoparticles , microscopic objects sized between 1 and 100 nanometers. Researchers are facing some hurdles in creating palladium nanoparticles with enough active surface area to be used as an efficient catalyst in fuel cells. Moreover, the researchers are facing another problem of preventing particles from diffusing together during the chemical processes that convert the hydrogen and oxygen into electricity. The particles, despite being solid, can touch one another and combine through the process of surface diffusion, reducing the total surface area and electrical energy output of the fuel cell.

palladium nanoparticles DOE

Palladium Nanoparticles. Source: U.S. DOE.

Two Brown University chemists have overcome these challenges. They claim that they have developed palladium nanoparticles with a 40% larger surface area. They also have addressed the problem of diffusion. Vismadeb Mazumder, graduate student, and assisting chemistry professor Shouheng Sun produced palladium nanoparticles 4.5 nanometers in size. They fastened the nanoparticles to a carbon platform at the anode end of a direct formic acid fuel cell. They utilized weak binding amino ligands to keep the palladium nanoparticles separate. This approach was the key to increasing the surface area. When the particles remain separate and uniform in size, they increase the available surface area on the platform and raise the efficiency of the fuel cell reaction, therefore more electricity is generated.

Fuel Cell Diagram

Diagram of Palladium Fuel Cell Reaction. Source: NAFTC.

An even greater approach to fuel cell technology may center on nanowire technology. Nanowires are sized in much the same way as nanoparticles except that they are cylindrical in shape. Scientists from the University of Rochester are planning to manufacture the longest platinum nanowires ever produced. These platinum nanowires may have an impact on the development of fuel cells for cars, trucks and other devices. The wires, which are 1/50,000 th the width of a human hair, are thousands of times longer than any previously made, according to a report in Nano Letters. The wires are ten nanometers in diameter and multiple centimeters in length, long enough to create the first self-supporting “web” of pure platinum that can be used in a fuel cell. James C. M. Li, professor of mechanical engineering at the University of Rochester, states, “People have been working on developing fuel cells for decades. But the technology is still not being commercialized. Platinum is expensive, and the standard approach for using it in fuel cells is far from ideal. These nanowires are a key step toward better solutions.”

Platinum nanowires increase the longevity and efficiency of fuel cells. Currently, nanowires are used only in spacecraft vehicles. The team of researchers at the University of Rochester believes that platinum nanowires can be exploited as modes of transport fuel. The main goal is to generate free-standing fuel cell catalysts from the nanowires. Since the molecular structure of platinum is naturally arranged in a thin wire, the particles comprising them do not need the carbon support structures to support them as nanoparticles require. With platinum arranged into a series of centimeter long, flexible, and uniformly thin wires, the particles comprising them are fixed in place and need no additional support. The platinum will no longer be lost during normal fuel cell operation.




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