Fig. 2: Surface composition of CoMnOx NPs from Co3p and Mn3p XP spectra. | Nature Communications

Fig. 2: Surface composition of CoMnOx NPs from Co3p and Mn3p XP spectra.

From: The role of manganese in CoMnOx catalysts for selective long-chain hydrocarbon production via Fischer-Tropsch synthesis

Fig. 2

a under 100 mTorr O2 at 300 °C. b under 100 mTorr H2 at 500 °C. Two photon energies, 770 eV and 270 eV were used (top and bottom spectra) to obtain a depth distribution profile based on the different mean-free paths of 1.2 and 0.6 nm respectively of the corresponding photoelectrons. The colored curves are fitting peaks for the 3p1/2 and 3p3/2 components for Co and Mn. The inset in the green box shows an expanded view of the Mn 3p XPS (hv = 270 eV) region in (b). c Co:Mn ratio in the top surface region (~0.6 nm, red points) and near surface region (~1.2 nm, black points) after oxidation and reduction treatments. The top surface of the activated catalyst contains Co0 and Mn2+ in a 2.5:1 ratio. d, e Co and Mn L-edge total electron yield XAS from CoMnOx NPs (red), after activation by heating in 1 bar of H2 at 450 °C. Spectra from known compounds (gray) are shown for comparison.

Back to article page