Fig. 4: Characterization of 1.1Co-S-1.
From: Mixed-valence Co0/IIOx clusters on silicalite-1 facilitate propane dehydrogenation to propene
a,b, AC-HAADF-STEM images of 1.1Co-S-1 with the insets showing the size distribution of the CoOx species (a) and an enlarged view of the region highlighted by the red square (b). dTEM in the inset in a means the diameter of CoOx determined by TEM. c, EXAFS spectra of 1.1Co-S-1 and reference samples CoO, Co3O4, Co2SiO4 and Co foil. The spectra are Fourier-transformed (‘IFT(R)I’) without phase correction. d, In situ XANES spectra at the Co K edge during heating from room temperature (RT) to 500 °C in He, followed by reduction in 50 vol% H2/He and then switching to a flow of 50 vol% C3H8/He at 500 °C. e, In situ UV–visible spectra recorded in the first 2 min of treatment of 1.1Co-S-1 in 40 vol% H2 at 500 °C. f, In situ XPS spectra of fresh 1.1Co-S-1 and the catalyst after treatment at 500 °C in 20 vol% O2 and 40 vol% H2.
