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article imageGraphene enhances fuel cell output

By Tim Sandle     Oct 16, 2014 in Science
Graphene quantum dots can attach graphene platelets to enhance the properties of the fuel cells. Tests have shown that graphene functions better than more expensive platinum catalysts.
The graphene quantum dots were created by James Tour, of Rice University. The dots were manufactured by creating a chemical hybrid from coal. Tour successfully combined these nanoscale dots with microscopic sheets of graphene (a one-atom-thick form of carbon). The resultant hybrid has proved effective at generating energy within fuel cells. A fuel cell is a device that converts the chemical energy from fuel into electricity through a chemical reaction with oxygen or another oxidizing agent.
Tour found, as he writes in a research note, that boiling down a solution of graphene quantum dots and graphene oxide sheets led to a substance formed of self-assembling nanoscale platelets. The platelets could then be treated with nitrogen and boron. This led to a hybrid material that captured the best properties of each constituent. These were: an abundance of edges where chemical reactions take place and powerful conductivity between graphene quantum dots provided by the graphene base. The boron and nitrogen contributed more catalytic action on the material.
The smoothness of the material was confirmed by electron microscopy. In tests, the new material showed an oxygen reduction reaction of about 15 millivolts more in positive onset potential (which relates to the start of the reaction) and 70 percent larger current density when compared with platinum-based catalysts.
The significance of the invention is that it is not only more efficient to run, it is far less expensive to manufacture than platinum based fuel cells.
The research was backed by The Office of Naval Research Multidisciplinary University Research Initiative (MURI) program, the Air Force Office of Scientific Research and its MURI program. The research has been published in American Chemical Society journal ACS Nano. The paper is titled “Boron- and Nitrogen-Doped Graphene Quantum Dots/Graphene Hybrid Nanoplatelets as Efficient Electrocatalysts for Oxygen Reduction.”
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