Operando Reactor-Cell with Simultaneous Transmission FTIR and Raman Characterization (IRRaman) for the Study of Gas-Phase Reactions with Solid Catalysts

Abstract

Raman and transmission FTIR spectroscopic techniques have been coupled in a new homemade reactor-cell designed in a joint CSIC-UNICAEN collaboration. The set-up is easily adapted to any FTIR and fibre-coupled Raman spectrometers and gas analysis techniques. Simultaneous operando FTIR and Raman spectroscopic measurement allow complementary characterization of adsorbed species, reaction intermediates, and structural properties of the catalyst. This system was validated with the study of vanadium based catalysts during propane OxyDeHydrogenation (ODH). The combined use of both spectroscopies with gas analysis techniques to measure the activity contributes to the understanding of propane ODH and the identification of the role of different oxygen species bound to vanadium sites. For example, the simultaneous characterization of the catalyst under the same conditions by IR and Raman confirms that the V=O mode has the same frequency in both spectroscopies, and that bridging oxygen sites (V-O-V, V-O-Zr) present higher activity than terminal V=O bonds. These results demonstrate the high potential of the new simultaneous transmission IR-Raman operando rig to correlate the activity and the structure of catalysts, thus assisting the rational design of catalytic processes.

Rapid scan FTIR reveals propane (am)oxidation mechanisms over vanadium based catalysts

“…One directly to propylene product and another to side reactions forming acetate, formate, ketones, aldehydes, and cyclic anhydride adsorbed species. This is in agreement with a recent study performed by simultaneous transmission FTIR and Raman spectroscopy, during propane ODH reaction over V based catalysts ( 37 ). There is also another opinion, since the bands at 1470 and 1445 cm -1 were also detected by Gong et al ( 38 ) during DRIFTS studies under propane ODH conditions with V/Al catalysts.…”

Operando Surface Spectroscopy and Microscopy during Catalytic Reactions: From Clusters via Nanoparticles to Meso‐Scale Aggregates

“…Vibrational infrared (IR) spectroscopy of adsorbed species and the catalyst material itself is a versatile operando method, [67,68,[73][74][75]85,[161][162][163][164][165][166] based on the absorption of broadband IR radiation (I 0 ) as measured by Fourier-transform (FT) spectrometers. As IR is not surface-specific, keeping the IR beam path in the gas phase short limits IR gas phase absorption (gas phase bands hold information on reactants and products, but may obscure surface species).…”

“…For other in situ/operando vibrational spectroscopy of active catalyst materials we refer to the literature (e.g., Raman [77][78][79][80][81]85,[122][123][124][125]163] and SFG [159,160,[169][170][171][172] ). The same ATR setup can also be used to study solid/liquid interfaces.…”

Optical Spectroscopy of Surfaces, Interfaces, and Thin Films

“…Understanding structure–activity relationships in catalysis is critical in optimizing catalytic performance and has gained increased importance as the scale of catalytic control has decreased to nanoscale dimensions. Bañares and Daturi and co-workers coupled fiber optic-based Raman and transmission FTIR spectroscopies along with gas phase analysis for operando characterization of catalysts . This approach facilitates complementary characterization of adsorbed species, reaction intermediates, and structural properties of the catalyst as nicely showcased in an investigation of a vanadium-based catalyst during propane oxy-dehydrogenation.…”

“…Banãres and Daturi and co-workers coupled fiber optic-based Raman and transmission FTIR spectroscopies along with gas phase analysis for operando characterization of catalysts. 114 This approach facilitates complementary characterization of adsorbed species, reaction intermediates, and structural properties of the catalyst as nicely showcased in an investigation of a vanadium-based catalyst during propane oxy-dehydrogenation. Specifically, this study Researchers at the Fritz Haber Institute utilized their new vibrational spectroscopy tool, surface action spectroscopy (SAS), to elucidate the structure of the topmost atomic layers in magnetite with and without surface water.…”