Fig. 2: Operando XAS studies of Rh-MFI-cal zeolite. | Nature Communications

Fig. 2: Operando XAS studies of Rh-MFI-cal zeolite.

From: Low-temperature hydroformylation of ethylene by phosphorous stabilized Rh sites in a one-pot synthesized Rh-(O)-P-MFI zeolite

Fig. 2

Evolution of the Rh K-edge XAS during operando studies in the Rh-MFI-cal sample. a Time-resolved XANES spectra at 50 °C, 10 bar and 30 mL/min reactant feed over a time interval of 250 min, (red to yellow and green) and after pressure decrease to 1 bar, 10 mL/min reactant feed and over a period of 100 min (blue lines). Spectra are overlaid with Rh(0) (blue dashes) and to Rh2O3 (black dashes) references; b Representative Fourier transformed k2-weigthed EXAFS signal along the reaction coordinate. The arrows showing the different contributions are only indicative. The EXAFS fitting results are reported in the Supplementary Information; c Evolution of the normalized spectral intensities at 23221 eV corresponding to Rh-CO/Rh(0) (blue) and 23240 eV corresponding to Rh2O3 (black); d Cauchy wavelet transform of spectra in (b) showing evolution of peaks between 1.2 and 2.2 Å indicative of interference from Rh-CO and Rh-O scattering as well as small amounts of Rh0 clustering in the final stages of the reaction (2.5 Å).

Back to article page