Operando photocatalytic cell for time-resolved XAS/GC analysis of gas phase CO₂ photoreduction

This article reports an operando X-ray absorption spectroscopy (XAS) cell and its set-up for the photocatalytic reduction of CO₂ in the gas phase. Details about the cell and set-up development and configuration are provided. The operando cell and set-up are validated from a photocatalytic point of view: the performances of two photocatalysts are successfully benchmarked with those obtained on an already existing gas phase photoreactor unit. The cell is also validated from an XAS point of view as measured Mo K-edge spectra of the photocatalyst loaded in the cell are similar to those measured for ex situ samples, prepared in a capillary. Finally, a detailed example of an operando photocatalytic experiment shows the potentiality of the developed cell to monitor photocatalysts under working conditions for gas phase CO₂ photoreduction, making the link between a shift in the absorption edge due to Mo species evolution and the deactivation of the photocatalyst. Additionally, the developed operando cell, available at Synchrotron SOLEIL on the ROCK beamline, is versatile and may actually be used for any photocatalytic gas phase reaction.