ABSTRACT Transient experimentation is broadly applied in heterogeneous catalysis as insights into surface dynamics can be retrieved. However, the nature and activity of the involved surface intermediates remain uncertain, impeding clear mechanistic conclusions. Thus, in this work, we extend transient experimentation with microkinetic modeling and spectroscopic techniques. In this study, CO 2 methanation experiments were performed on a supported catalyst (Ru/TiO 2 ) using the Periodic Transient Kinetics (PTK) method. Elemental balances based on the transient results showed decoupled hydrogenation pathways and storage behavior for surface carbon and oxygen species. The nature of these species was elucidated by Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) studies providing evidence for support‐bound species. Potential lumped mechanisms were formulated discriminating between species adsorbed on the support or active material. On the basis of these mechanisms, microkinetic models were set up, fitted to the experimental data and compared by their deviation to the transient experimental data. By comparing the steady‐state coverage of the simulated surface to the spectroscopic results, plausibility was checked. We show that DRIFTS, PTK, and microkinetic modeling provide complementary data in a way that quantitative mechanistic information can be obtained. This synergy is only possible using dynamic experimentation.
Zirn et al. (Fri,) studied this question.