EVOLUTION OF NI-YSZ MICROSTRUCTURE AND ITS RELATION TO STEAM REFORMING ACTIVITY AND YSZ PHASE STABILITY

Conference · Wed Jan 30 04:00:00 EST 2008

OSTI ID:981594

King, David L; Strohm, James J; Singh, Prabhakar

Internal steam reforming of methane within solid oxide fuel cells (SOFC) offers a method of improved thermal management and reduced system complexity. Thermal gradient management is dependent upon controlling the reforming activity along the length of the anode. The inherent activity of Ni-YSZ for the steam reforming of methane is highly dependent upon the pretreatment and reduction procedures employed. During reductive pretreatment of the anode, small Ni crystallites can exolve from the YSZ to provide a significant component to the initial catalytic activity. This activity decreases with time as the small Ni crystallites sinter. Control of this microstructure is key to controlling the thermal gradients along the anode. NiO initially dissolved in 5YSZ increases the amount of undesirable monoclinic phase, and the exolution of Ni crystallites during reduction results in a reduction in the monoclinic phase. With 8YSZ, nickel also dissolves and exolves from the YSZ particles but no monoclinic phase is observed.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 981594
• Report Number(s): PNNL-SA-58926; AA2530000
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
30 DIRECT ENERGY CONVERSION
CERAMICS
CONTROL
ENGINEERING
EVOLUTION
LENGTH
MANAGEMENT
METHANE
MICROSTRUCTURE
NICKEL
PARTICLES
PHASE STABILITY
PROCEEDINGS
REDUCTION
SOLID OXIDE FUEL CELLS
STEAM
TEMPERATURE GRADIENTS