INSITU DRIFT SPECTROSCOPY IN A CONTINUOUS RECYCLE REACTOR - A VERSATILE TOOL FOR CATALYTIC PROCESS RESEARCH

Diffuse Reflectance Infrared Fourier-Transform (DRIFT) spectroscopy is an increasingly popular technique in catalysis research as it permits in-situ observation of the reactor bed in powdered or granular form. However, DRIFTS in its conventional form suffers from temperature-gradient problems. One solution is to couple the DRIFTS cell with a continuous recycle flow system. The value of such an arrangement is illustrated via studies, of the kinetics and mechanism of CO2 methanation over Ru/TiO2 under transient and steady-state conditions. Metal-absorbed CO is identified as the main reaction intermediate through titration to CH4 in transient hydrogenation. The CO(ad) is probably supplied via rapid establishment of the reverse water gas shift equilibrium: H2 + CO2 --> CO(ad) + H2O involving adsorbed formate intermediate(s).