title: Multivariate curve resolution applied to in situ X-ray absorption spectroscopy data: an efficient tool for data processing and analysis.
abstract: Large datasets containing many spectra commonly associated with in situ or operando experiments call for new data treatment strategies as conventional scan by scan data analysis methods have become a time-consuming bottleneck. Several convenient automated data processing procedures like least square fitting of reference spectra exist but are based on assumptions. Here we present the application of multivariate curve resolution (MCR) as a blind-source separation method to efficiently process a large data set of an in situ X-ray absorption spectroscopy experiment where the sample undergoes a periodic concentration perturbation. MCR was applied to data from a reversible reduction-oxidation reaction of a rhenium promoted cobalt Fischer-Tropsch synthesis catalyst. The MCR algorithm was capable of extracting in a highly automated manner the component spectra with a different kinetic evolution together with their respective concentration profiles without the use of reference spectra. The modulative nature of our experiments allows for averaging of a number of identical periods and hence an increase in the signal to noise ratio (S/N) which is efficiently exploited by MCR. The practical and added value of the approach in extracting information from large and complex datasets, typical for in situ and operando studies, is highlighted.
authors.affiliation: Department of Chemical Engineering, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway.
authors.forename: Alexey
authors.initials: A
authors.lastname: Voronov
authors.affiliation: Institute of Chemical Research of Catalonia (ICIQ), 43007 Tarragona, Spain. Electronic address: aurakawa@iciq.es.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Urakawa
authors.affiliation: The Swiss-Norwegian Beamlines (SNBL) at ESRF, BP 220, F-38043 Grenoble, France. Electronic address: wouter@esrf.fr.
authors.forename: Wouter
authors.initials: W
authors.lastname: van Beek
authors.affiliation: Department of Chemical Engineering, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway.
authors.forename: Nikolaos E
authors.initials: NE
authors.lastname: Tsakoumis
authors.affiliation: The Swiss-Norwegian Beamlines (SNBL) at ESRF, BP 220, F-38043 Grenoble, France.
authors.forename: Hermann
authors.initials: H
authors.lastname: Emerich
authors.affiliation: Department of Chemical Engineering, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway. Electronic address: magnus.ronning@ntnu.no.
authors.forename: Magnus
authors.initials: M
authors.lastname: Rønning
keywords: In situ; Modulation; Multivariate curve resolution; Operando; X-ray absorption spectroscopy