Air Electrode in Hydrogen Fuel Cell Physics REU

Hydrogen Fuel Cell external circuit Air electrode cathode anode H 2 source H 2

Cross Sectional View of the Air Electrode n Gore-tex Gold PEDOT n Carbon Aerosol

Gore-tex Fabric n n Hydrophobic - keeps electrolyte from going through the pores Porous

Carbon Aerosol Gel n n n Acetylene or ethylene with oxygen are kept in

PEDOT poly(3, 4 -ethylenedioxythiophene) n n Low electrical conductivity: gold layer is needed O

Experimental Process n Carbon aerosol gel is pressed on Goretex q Resistance varies from

Testing Air Electrode n n Half of the hydrogen fuel cell Electrolyte: 1 M

Future Plans n n Air electrode needs to be tested in an oxygen free

Acknowledgments n I would like to thank: q q q NSF for funding Dr.

Slides: 12

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Air Electrode in Hydrogen Fuel Cell Physics REU 2012 Diana Gutierrez Zedano Mentors: Dr. Flanders & Dr. Sorenson

Hydrogen Fuel Cell external circuit Air electrode cathode anode H 2 source H 2 2 H+ + 2 e. O 2 + 4 e- 2 O 2 - reduction H+ electrolyte varies O 2 - O 2 in air 2 H+ + O 2 - H 2 O green waste

Cross Sectional View of the Air Electrode n Gore-tex Gold PEDOT n Carbon Aerosol Gel n n Bjorn Winther-Jensen et all. High Rates of Oxygen Reduction over a Vapor Phase–Polymerized PEDOT Electrode. Science. August 2008: 671 -674

Gore-tex Fabric n n Hydrophobic - keeps electrolyte from going through the pores Porous - “breathable” Academy of Art University of San Francisco

Carbon Aerosol Gel n n n Acetylene or ethylene with oxygen are kept in a fuel rich chamber and ignited by a spark. This produces an incomplete combustion which allows for the aggregation of carbon particles Pores confined within fractal structure Black color (like PEDOT): use Raman spectrum to differentiate q Bands: D 1330, G 1580, G’ 2646

PEDOT poly(3, 4 -ethylenedioxythiophene) n n Low electrical conductivity: gold layer is needed O 2 reduction catalyst O 2 + 4 e- 2 O 2 - n n Wikipedia Not sensitive to carbon monoxide Raman Spectrum Band: Double carbon bond

Experimental Process n Carbon aerosol gel is pressed on Goretex q Resistance varies from 25 to 3 kilo ohms n Electro deposition of gold on carbon-coated Goretex. q 20 m. M HAu. Cl 4 q 2 V DC n Electro polymerization of PEDOT film on gold-coated Goretex. q 10 m. M EDOT and 20 m. M PSS q 2 V DC

Raman Spectrum for Air Electrode

Testing Air Electrode n n Half of the hydrogen fuel cell Electrolyte: 1 M H 2 SO 4 Copper tape Pt Counter Electrode H 2 SO 4 Working Electrode O 2 + 4 e- 2 O 2 - O 2 in air

Air electrode test data

Future Plans n n Air electrode needs to be tested in an oxygen free environment. Work out a method to enhance the amount of PEDOT deposition

Acknowledgments n I would like to thank: q q q NSF for funding Dr. Flanders and Dr. Sorenson who guided me through the project Govind Paneru for teaching me the skills I needed for my project Dr. Flanders, Dr. Sorenson and Arjun Nepal who made the carbon aerosol gel sample Dr. Weaver and Dr. Corwin for coordinating the program