US Patent 7229944 - Carbon fiber sheet

http://www.freepatentsonline.com/7229944.html

Catalytic membranes are a component of fuel cells that can help speed up reactions and improve efficiency. This patent from M.I.T. discloses catalytic membranes formed using carbon nanofibers. Claim 1 reads:

1. A structure comprising: a carbon fiber sheet-like structure having a thickness of less than 10 microns and including at least one carbon fiber having a length of greater than about 500 microns; and a catalytic material supported on the carbon fiber sheet-like structure, wherein carbon fiber of the structure has an average diameter of less than about 500 nanometers.

US Patent 7189472 - Nanofibers for fuel cell

http://www.freepatentsonline.com/7189472.pdf

The large surface-to-volume ratio of nanostructured materials has made these materials favorable as catalytic carriers for fuel cells. This patent from Toshiba uses nanofibers with high aspect ratios with aluminum oxide powder to improve power efficiency of fuel cells. Claim 1 reads:

1. An electrode for a fuel cell comprising: a film including: carbon nano-fibers having particle diameters of 5-1000 nm and an aspect ratio of particle diameter to particle length of from 1:10 to 1:1000; aluminum oxide powder; fuel cell catalyst carried on a surface of said carbon nano-fibers; and ion conductive material.

US Patent 7179561 - Nanowires on fuel cell membrane

http://www.freepatentsonline.com/7179561.pdf

This patent from Nanosys provides some basic claims toward the manufacture and structure of improved fuel cells including catalytic particles on the surface of nanowires to achieve higher efficiencies and power densities. Claim 1 reads:

1. A fuel cell comprising inorganic nanowires which are derivatized with at least a first functional group which binds to a metal catalyst deposited on a surface of the nanowires, wherein the nanowires are deposited or directly grown on a proton exchange membrane of the fuel cell.

US Patent 7172747 - Double Helix Metal Oxide Nanotube

http://www.freepatentsonline.com/7172747.pdf

Nanoparticulate materials have attracted much interest in the area of hydrogen storage (useful for fuel cells) due to the high surface to volume ratio of these materials. This patent from Japan Science and Technology Agency claims a newly discovered nanomaterial in the form of a double helix nanotube made of metal oxide material. Claim 1 reads:

1. A metal oxide nanotube consisting solely of a metal oxide that may contain hydroxyl groups, which is constructed in a double spiral and a hollow cylinder and has a hole diameter distribution containing two peak hole diameters ranging from 1 to 2 nm and from 3 to 7 nm.

US Patent 7171841 - Nanocluster Hydrogen Sensor

http://www.freepatentsonline.com/7171841.pdf

Hydrogen fuel cells require the use of hydrogen sensors for concentration and leak detection. This patent uses metal atom nanoclusters to form hydrogen sensors of higher reaction speed with greater energy efficiency. Claim 1 reads:

1. A device, comprising a non-conducting substrate having thereon, a metal film comprised of nanoclusters of metal atoms capable of absorbing hydrogen to form a stable metal hydride, said metal film being on the threshold of percolation, and mechanism in electrical communication with said metal film for sensing a change in electrical resistance in response to the presence of hydrogen in contact with said metal film, whereby hydrogen absorbed by said metal film forms a metal hydride larger in volume than the metal resulting in percolation of said metal film and an increase in the conductivity thereof; and wherein said non-conducting substrate has a stiction-reducing coating thereon.