Operando Laboratory‐Based Multi‐Edge X‐Ray Absorption Near‐Edge Spectroscopy of Solid Catalysts

Abstract

Laboratory-based X-ray absorption spectroscopy (XAS) and especially X-ray absorption near-edge structure (XANES) offers new opportunities in catalyst characterization and presents not only an alternative, but also a complementary approach to precious beamtime at synchrotron facilities. We successfully designed a laboratory-based setup for performing operando, quasisimultaneous XANES analysis at multiple K-edges, more specifically, operando XANES of mono-, bi-, and trimetallic CO 2 hydrogenation catalysts containing Ni, Fe, and Cu. Detailed operando XANES studies of the multielement solid catalysts revealed metal-dependent differences in the reducibility and re-oxidation behavior and their influence on the catalytic performance in CO 2 hydrogenation. The applicability of operando laboratory-based XANES at multiple K-edges paves the way for advanced multielement catalyst characterization complementing detailed studies at synchrotron facilities.

An Advanced Characterization Toolbox for Selective Olefin Oxidation Catalysts

“…[25] Due to the high demand for such studies, laboratory based XRD and XAS studies have strongly come into focus. [36][37] These offer the great advantage of easy accessibility and thus give a new opportunity for in house XAS studies, e. g. catalyst screenings. However, due to low photon flux, time- resolved in situ/operando studies including spatially-resolved approaches are currently hardly feasible with such setups.…”

“…At its core, a quartz glass capillary serves as fixed‐bed reactor with optimal heat and mass transfer properties [25] . Due to the high demand for such studies, laboratory based XRD and XAS studies have strongly come into focus [36–37] . These offer the great advantage of easy accessibility and thus give a new opportunity for in house XAS studies, e. g .…”

The Necessity for Multiscale In Situ Characterization of Tailored Electrocatalyst Nanoparticle Stability

“…This is of particular relevance for bimetallic nanoparticles, to elucidate whether stable alloys or phase separated structures are formed during the reaction. Similar developments for in house X-ray absorption spectroscopy , as for in house XRD measurement would further speed up material development for CO 2 reduction. In this way, more materials can be screened and developed within a shorter time frame without the need for costly and time-consuming beamtime applications at the synchrotron.…”

Laboratory-scale X-ray absorption spectroscopy of 3d transition metals in inorganic thin films

“…Their applicability e.g. , for electrochemistry, 28,29 catalysis, 30–32 and actinide 33 research have been demonstrated. Laboratory-scale instruments provide an easy access to XAS, and enable long-term experimental campaigns.…”

“…Fortunately, in the recent years the capabilities of laboratory-scale XAS spectrometers have continuously increased in hard X-ray, [17][18][19][20][21][22][23][24] tender X-ray, 25 and soft X-ray 26,27 ranges. Their applicability e.g., for electrochemistry, 28,29 catalysis, [30][31][32] and actinide 33 research have been demonstrated. Laboratory-scale instruments provide an easy access to XAS, and enable long-term experimental campaigns.…”