Capturing the Genesis of an Active Fischer–Tropsch Synthesis Catalyst with Operando X‐ray Nanospectroscopy

Abstract

A state-of-the-art operando spectroscopic technique is applied to Co/TiO catalysts, which account for nearly half of the world's transportation fuels produced by Fischer-Tropsch catalysis. This allows determination of, at a spatial resolution of approximately 50 nm, the interdependence of formed hydrocarbon species in the inorganic catalyst. Observed trends show intra- and interparticular heterogeneities previously believed not to occur in particles under 200 μm. These heterogeneities are strongly dependent on changes in H /CO ratio, but also on changes thereby induced on the Co and Ti valence states. We have captured the genesis of an active FTS particle over its propagation to steady-state operation, in which microgradients lead to the gradual saturation of the Co/TiO catalyst surface with long chain hydrocarbons (i.e., organic film formation).

Formation and Functioning of Bimetallic Nanocatalysts: The Power of X‐ray Probes

“…On the one hand, X‐ray techniques allowing milli‐ to femtosecond time resolution have strong potential to uncover currently scarce kinetic descriptions of transient changes in catalytic solids and molecular adsorption–desorption phenomena under reaction conditions, respectively. On the other hand, the avenue of spatially resolved X‐ray micro‐ and nanoscopy will provide the means to map the composition and structure of metal catalyst particles and single crystals under real conditions, for example by (S)TXM, μ‐XRD‐CT, or CDI, uncovering particle heterogeneities commonly present in heterogeneous catalysts . As the spatial resolution of state‐of‐the‐art X‐ray nanoscopes (ca.…”

In‐situ X‐Ray Absorption Near Edge Structure Spectroscopy of a Solid Catalyst using a Laboratory‐Based Set‐up

“…The cobalt loading obtained was 14.1 wt %, which was confirmed by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). [40] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 The crystal size was estimated by X-Ray Diffraction (XRD) data analysis and confirmed by Scanning Transmission Electron Microscopy-Energy Dispersion X-ray Spectroscopy (STEM-EDX).…”

Impact of small promoter amounts on coke structure in dry reforming of methane over Ni/ZrO2

“…Ideally, the reaction temperature should be low to reduce energy consumption and thus costs. High-pressure operation would also be economically preferable to a compression of the more voluminous syngas for use in syntheses at elevated pressure (e.g., Fischer-Tropsch (FT) 4 or methanol 5 syntheses). 6 At low temperature and high pressure, the side-reactions producing coke are thermodynamically most favourable, however (Fig.…”