Surface Reaction Fundamentals inDirect Oxidation Hydrocarbon Fuel Cells

Eric M. Stuve, University of Washington

OBJECTIVES• Examine fundamental surface chemistry of

electrolytic hydrocarbon oxidation reactions– Intermediates– Reaction pathways– Kinetic parameters

• Characterize fuel / catalyst combinations– Ceria / metal catalyzed direct oxidation of hydrocarbons– Catalysts for direct hydrocarbon oxidation < 700 °C– Bond breaking tendencies for C–C, C–H, and C–O – Role of surface / substrate oxygen in direct oxidation– Fuels for proton / oxygen ion conducting electrolytes

APPROACH• Ceria / catalyst coated field emitter tip

– Work function studies by FEM– Imaging with FIM / FDM– Ionization monitored by ToF and ExB filter

• UHV Solid Oxide Fuel Cell (SOFC) – Surface analysis of catalyst / oxide (XPS, LEIS, etc.)– Reaction pathways and kinetics

DoD PAYOFFProvide fundamental information about relative tendencies of bond breaking in electrocatalysis, surface reaction intermediates, carbon deposition, and the role of oxygen in direct hydrocarbon oxidation important for an overall understanding of direct oxidation hydrocarbon fuel cells.

Pt TIP

CxHy

CO2

H2O

O2– O2–O2– O2–O2–SOLID OXIDE

OO

MOxOO O

OO

O2–O2–

TPB

CATALYST

SIDE VIEW FRONT VIEW

Pt TIP

CxHy

CO2

H2O

O2– O2–O2– O2–O2–SOLID OXIDE

OO

MOxOO O

OO

O2–O2–

TPB

CATALYST

SIDE VIEW FRONT VIEW