Monitoring the Reaction Mechanism in Model Biogas Reforming by In Situ Transient and Steady‐State DRIFTS Measurements

Abstract In this work, the reforming of model biogas was investigated on a Rh/MgAl 2 O 4 catalyst. In situ transient and steady‐state diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) measurements were used to gain insight into the reaction mechanism involved in the activation of CH 4 and CO 2 . It was found that the reaction proceeds through of an initial pathway in which methane and CO 2 are both dissociated on Rh metallic sites and additionally a bifunctional mechanism in which methane is activated on Rh sites and CO 2 is activated on the basic sites of the support surface via a formate intermediate by H‐assisted CO 2 decomposition. Moreover, this plausible mechanism is able to explain why the observed apparent activation energy of CO 2 is much lower than that of CH 4 . Our results suggest that CO 2 dissociation facilitates CH 4 activation, because the oxygen‐adsorbed species formed in the decomposition of CO 2 are capable of reacting with the CH x species derived from methane decomposition.