IN-SITU FT1R STUDIES OF Rh SUBSTITUTED LANTHANUM ZIRCONATE (La2Zr2O7) PYROCHLORES FOR CO2 REFORMING OF CH4

摘要

Dry (CO2) reforming of methane (DRM) to form CO and H2 has been studied over a wide range of catalysts. The reaction requires temperatures above 800°C to produce high conversions. DRM is also inevitably accompanied by carbon deposition. This in turn requires catalysts that are both thermally stable and resistant to carbon deposition. Despite the well-known thermal stability and oxygen conductivity of substituted pyrochlores, we are aware of no literature except that of Ashcroft et.al on the DRM reaction using pyrochlores. In that study, a Eu-Ir pyrochlore decomposed at DRM conditions. Here, we report DRM on Rh-substituted lanthanum zirconate pyrochlores with varying wt % metal loadings of 0% [LZ], 2% [LRhZ (2%)] and 5% [LRhZ (5%)]. The substitution of appropriate elements into the pyrochlore structure produces thermally and chemically stable catalysts that are resistant to carbon formation due to improved oxygen-ion conductivity. In this work we study in-situ FTIR spectra in flowing CO2 and CH4 and determine the adsorbed surface species at reaction conditions.