hydrogen fuel cells the power of tomorrow BY

hydrogen fuel cells: the power of tomorrow BY ALLEN DEARMOND AND LAUREN CUMMINGS

Generates electric power using a fuel and an oxidant � Unlike a battery, chemicals are not stored in the fuel cell; they must be replenished � Possible fuel sources: hydrogen, alcohols, hydrocarbons, gasoline � Possible oxidants: oxygen, chlorine dioxide � Refueling of an internal combustion engine, efficient and quiet like a battery �

� Polymer Electrolyte Membrane (PEM) Fuel Cells � Direct Methanol Fuel Cells � Alkaline Fuel Cells � Phosphoric Acid Fuel Cells � Molten Carbonate Fuel Cells � Solid Oxide Fuel Cells � Regenerative Fuel Cells

� � � Anode (-) and Cathode (+) on each side of the fuel cell, divided by an electrolyte Hydrogen gas is channeled through anode side; oxygen passes through cathode Platinum catalyst oxidizes hydrogen atoms into H+ and electrons Electrons pass along external circuit; conduct electricity before entering cathode Electrolyte allows H+ to pass into the cathode In cathode, catalyst combines H+ , O 2 - and electrons, forming H 2 O and heat

� Anode: 2 H 2 => 4 H+ + 4 e� Cathode: O 2 + 4 H+ + 4 e- => 2 H 2 O � Net Reaction: 2 H 2 + O 2 => 2 H 2 O � Exact opposite of electrolysis

Catalyst: increases rate of reaction without being consumed in the process � Platinum is main catalyst used in PEM fuel cells � Platinum is expensive and highly sensitive to poisoning � New platinum/ruthenium catalysts being researched for use in hydrogen fuel cells � Reaction requires lower temperatures and high humidity and pressure �

� � � � Little-to-no pollution, doesn’t need to be recharged 2500 fuel cell systems have been installed globally Used to power landfills and water treatment plants 50 fuel cell buses Every major automotive manufacturer has designed a fuel cell-powered vehicle Mercedes-Benz projects 40% efficiency in compact cars running on Hydrogen fuel cells Hydrogen Fuel Initiative (2003)

Fuel cells require specific humidity, pressure, etc. � Catalysts are pricey and sensitive to poisoning � Difficult to produce hydrogen � Difficult to store optimum amounts of Hydrogen � If fuels other than hydrogen are used, some greenhouse gasses are emitted � Very few cars currently running on hydrogen �

� � � Used to power personal electronic devices: cell phones, i. Pods, laptops Enough energy to run for days, or weeks (instead of hours) Potentially power all cars, airplanes, ships, etc. 60 million tons of carbon dioxide could be eliminated from yearly greenhouse gas production Development of cheaper and more reliable catalysts Higher demand = cheaper

� Economic crisis has greatly slowed technological advancements � Past predictions for 2010 seem unlikely � Hydrogen cannot be the only alternative fuel source to solve the energy crisis � Many more years of research before mass production will be possible

� Hydrogen fuel cells are efficient, and clean � Also expensive, and require specific humidity, temperature, pressure � With more technological advancements, could be used in mass production for various applications � Not an instant fix for the energy crisis, but definitely a major component

� � � Basic Elements: Fuel for the Future. Miramar High School. 3 March 2009. <http: //library. thinkquest. org/04 apr/00 215/energy/fuel_cells. htm> Fuel Cells. Princeton University. 3 March 2009. <http: //www. princeton. edu/~ch m 333/2002/spring/Fuel. Cells/> Fuel Cells. U. S. Department of Energy. 9 March 2009. <http: //www 1. eere. energy. gov/hydrogenandfuelcells/fu elcells/fc_types. html> Hydrogen. gov United States Government. 10 March 2009. <http: //www. hydrogen. gov>. Nice, Karim and Jonathan Strickland. “How Fuel Cells Work. ” 18 September 2000. How Stuff Works. com. <http: //www. howstuffworks. com/fuel-cell. htm 3 March 2009>.