Operando monitoring of metal sites and coke evolution during non-oxidative and oxidative ethanol steam reforming over Ni and NiCu ex-hydrotalcite catalysts

ROCK: A Beamline Tailored for Catalysis and Energy-Related Materials from ms Time Resolution to µm Spatial Resolution

“…Thanks to optical fibers and long working-distance objectives, Raman spectra can be collected on the three cells available for catalysis (directly through the quartz capillaries or through a 25 µm mica window for the Lytle-type cell). Raman spectroscopy can provide complementary information about the sample's structure [13][14] and also about surface carbonaceous deposits [15][16]. As an example, the combination of QEXAFS and Raman spectroscopy has recently been applied to monitor the deactivation of Co/Al 2 O 3 catalyst during ethanol steam reforming (ESR) carried out at 500°C under a He flow saturated with C 2 H 5 OH/H 2 O in the ratio 1:6, and, its subsequent regeneration under oxidative atmosphere [15].…”

“…ROCK scientists have been very active in the past ten years for the use of Multivariate Curve Resolution with Alternating Least Squares fitting (MCR-ALS) for XAS data. The methodology available on ROCK is now well established and involves (i) Principal Component Analysis -Singular Value Decomposition (PCA-SVD) to identify the number of components needed to fully represent the variance of the dataset, and (ii) MCR-ALS to extract, on the basis of the bilinear decomposition of the dataset obeying to the Beer-Lambert law, spectra of the pure components involved in the reaction together with their concentration profiles [4,[14][15][16][17][18]. An example of speciation so-obtained by MCR-ALS for the Mo K edge data presented in Figure 2 (a) is shown in Figure 2 (c).…”

Quick-EXAFS and Raman monitoring of activation, reaction and deactivation of NiCu catalysts obtained from hydrotalcite-like precursors

“…We have already reported that the simultaneous monitoring of ESR reaction/regeneration cycles by Quick-EXAFS and Raman spectroscopy can be efficiently used for proposing regeneration protocols carried out at the same temperature than the ESR reaction. 6,24 This regeneration route involved either the simultaneous use of ESR reactant mixture with the controlled addition of O 2 24 or the stop of ESR feed to introduce O 2 . 6 We evidenced that the oxidative regeneration burned coke and partially oxidized metallic M 0 particles.…”

“…6,24 This regeneration route involved either the simultaneous use of ESR reactant mixture with the controlled addition of O 2 24 or the stop of ESR feed to introduce O 2 . 6 We evidenced that the oxidative regeneration burned coke and partially oxidized metallic M 0 particles. After regeneration, the catalysts were self-reactivated thanks to the hydrogen produced by the ESR reaction (1).…”

“…Ni-Cu-Al LDH precursor was produced by sol-gel route according to a previously described method. 6 Briefly, for the synthesis of the bimetallic NiCu catalyst, first, 0.…”