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SUMMARY:Sunlight-Driven Hydrogen Formation by Membrane-Supported Photoelec
 trochemical Water Splitting
DTSTART:20150505T101500
DTEND:20150505T111500
DTSTAMP:20260406T225932Z
UID:8a395194cea7efdd2a3e4498ee9462b2c0af847ce6beaac5faaf2db9
CATEGORIES:Conferences - Seminars
DESCRIPTION:Professor Nathan. S. Lewis\, California Institute of Technolog
 y\, Beckman Institute and Kavli Nanoscience Institute\nBio : Dr. Nathan S.
  Lewis is the George L. Argyros Professor of Chemistry at the California I
 nstitute of Technology and the Scientific Director of the Joint Center for
  Artificial Photosynthesis\, the DOE’s Energy Innovation Hub in Fuels fr
 om Sunlight.  Professor Lewis is Principal Investigator of the Beckman In
 stitute Molecular Materials Resource Center.  His research interests incl
 ude artificial photosynthesis and electronic noses. Nate continues to stud
 y ways to harness sunlight and generate chemical fuel by splitting water t
 o generate hydrogen. He is developing the electronic nose\, which consists
  of chemically sensitive conducting polymer film capable of detecting and 
 quantifying a broad variety of analytes. Technical details focus on light-
 induced electron transfer reactions\, both at surfaces and in transition m
 etal complexes\, surface chemistry and photochemistry of semiconductor/liq
 uid interfaces\, novel uses of conducting organic polymers and polymer/con
 ductor composites\, and development of sensor arrays that use pattern reco
 gnition algorithms to identify odorants\, mimicking the mammalian olfactio
 n process.\nAbstract : we are developing an artificial photosynthetic syst
 em that will utilize sunlight and water as inputs and will produce hydroge
 n and oxygen as outputs using a modular\, parallel development approach in
  which the three distinct primary components-the photoanode\, the photocat
 hode\, and the product-separating but ion-conducting membrane-are fabricat
 ed and optimized separately before assembly into a water-splitting system.
  The design principles incorporate two separate\, photosensitive semicondu
 ctor/liquid junctions that will collectively generate the 1.7-1.9 V at ope
 n circuit to support both the oxidation of H2O (or OH-) and the reduction 
 of H+ (or H2O). The photoanode and photocathode will consist of rod-like s
 emiconductor components\, with attached heterogeneous multi-electron trans
 fer catalysts\, needed to drive the oxidation or reduction reactions at lo
 w overpotentials.  The high aspect-ratio semiconductor rod electrode arch
 itecture allows for the use of low cost\, earth abundant materials without
  sacrificing energy conversion efficiency due to orthogonalization of ligh
 t absorption and charge-carrier collection.  Additionally\, the high surf
 ace-area design of the rod-based semiconductor array electrode inherently 
 lowers the flux of charge carriers over the rod array surface relative to 
 the projected geometric surface of the photoelectrode\, lowering the photo
 current density at the solid/liquid junction and thereby relaxing demands 
 on the activity (and cost) of any electrocatalysts.  Flexible composite p
 olymer film will allow for electron and ion conduction between the photoan
 ode and photocathode while simultaneously preventing mixing of the gaseous
  products.  Separate polymeric materials will be used to make electrical 
 contact between the anode and cathode and also provide structural support.
   Interspersed patches of an ion conducting polymer will maintain charge 
 balance between the two half-cells.  The modularity design approach allow
 s each piece to be independently modified\, tested\, and improved\, as fut
 ure advances in semiconductor\, polymeric\, and catalytic materials are ma
 de.  This work will demonstrate a feasible and functional prototype and b
 lueprint for an artificial photosynthetic system\, composed of inexpensive
 \, earth-abundant materials while simultaneously efficient\, durable\, man
 ufacturably scalable\, and readily upgradeable.
LOCATION:AAC231 http://plan.epfl.ch/?room=AAC231
STATUS:CONFIRMED
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