<i>In Situ</i> X-ray Raman Scattering Spectroscopy of the Formation of Cobalt Carbides in a Co/TiO<sub>2</sub> Fischer–Tropsch Synthesis Catalyst
José G. Moya‐Cancino, A. Honkanen, Ad M. J. van der Eerden, Ramon Oord, Matteo Monai, Iris C. ten Have, Christoph J. Sahle, Florian Meirer, Bert M. Weckhuysen, Frank M. F. de Groot, Simo Huotari
Abstract
We present in situ experiments to study the possible formation of cobalt carbides during Fischer–Tropsch synthesis (FTS) in a Co/TiO2 catalyst at relevant conditions of pressure and temperature. The experiments were performed by a combination of X-ray Raman scattering (XRS) spectroscopy and X-ray diffraction (XRD). Two different experiments were performed: (1) a Fischer–Tropsch Synthesis (FTS) reaction of an ∼14 wt % Co/TiO2 catalyst at 523 K and 5 bar under H2 lean conditions (i.e., a H2:CO ratio of 0.5) and (2) carburization of pure cobalt (as reference experiment). In both experiments, the Co L3-edge XRS spectra reveal a change in the oxidation state of the cobalt nanoparticles, which we assign to the formation of cobalt carbide (Co2C). The C K edge XRS spectra were used to quantify the formation of different carbon species in both experiments.