SU Hui , WU Yefan
(Lab of New Energy Research, Jingdezhen Ceramic Institute, Jingdezhen Jiangxi 333001,China)
Abstract: The DR-FTIR spectra of adsorbed CH4 on Ni-YSZ anode at 600℃, 700℃ and 800℃ show that the absorption peaks in 2937 and 2860cm -1 occur in the CH3 asymmetric and symmetric stretching vibration bands. It's caused by the CH4 dissociation in the active metal site of Ni on the anode, the abstraction of hydrogen and the production of CHx (x = 1 ~ 3). Calculation results show that, of the four possible dissociations of CH4 molecules on a Ni-based anode, the configuration of the intermediate products from the first three cannot be convergent, and thus the likelihood of the three reactions is small. Optimizing the fourth can produce a stable intermediate configuration. This indicates that, with the C-H bond of CH4 close to Ni support weakly activated by Ni atoms, a strongly -bonded atom -molecule NiCH4 complex is formed, lowering the symmetry of CH4 from Td to C2v, and making the infrared forbidden band split and detectable in the experiment. The calculation results are consistent with those of the experiment.
Key words: infrared spectroscopy; SOFC; absorption peak; activation