Operando studies of carbon removal and contaminants in solid oxide fuel cells

Solid oxide fuel cells (SOFCs) are attractive devices for power generation due to their fuel flexibility. These devises present challenges for real time, direct observations because they operate at high temperatures (> 700 °C). We have developed and used several methods for real-time, operando studies, including infrared emission, near infrared thermal imaging and Raman spectroscopy which are combined with ex situ infrared spectroscopy and mass spectrometry of the products and concurrent electrochemical measurements for comprehensive investigations of the effects of contaminants and remediation approaches. We characterized the products, primarily CO and CO₂, as well as anode temperature changes to explore the effects of various mixtures of H₂ and O₂ on carbon removal from Ni-YSZ anodes as well as during partial methane oxidation for SOFC operation. The prevalent processes effectively reduce to steam reforming with hydroxyl as a primary reaction intermediate. We also report initial studies of sulfur effects based on SOFC operation with methane and compare the results to similar studies for chlorine degradation to identify whether there are common themes.