Unoccupied electronic structure and core-hole effects in the x-ray-absorption spectra ofCu2O

Characterising the surface and interior chemistry of core–shell nanoparticles using scanning transmission electron microscopy

“…it has a broader high energy 'tail'. These observations are consistent with a Cu 2 O spectrum rather than CuO (for the latter the L 3 white line is symmetrical and there is a ~2.5 eV chemical shift to lower energy loss with respect to pure Cu [21][22]). From the relative intensities of the extracted Cu L 2,3 -core and shell spectra it is possible to calculate the volume density ratio (ρ Cu ) of Cu atoms in the core region with respect to the shell region along the lines described in section 4.1.…”

“…The intensity of the extracted core spectrum does not decrease even at energies as large as 100 eV above the edge onset. The extracted shell spectrum shows a stronger L 3 white line intensity as required for a Cu-oxide [21][22] but there is a sudden decrease in intensity above ~1020 eV. Thus both extracted core and shell spectra do not give the correct edge shapes at high energy losses.…”

Real-space multiple-scattering analysis of Ag L 1- and L 3-edge XANES spectra of Ag2O

“…The fact that core hole effects d states much more than p states was observed also for Cu20 (Grioni et al 1992) and for transition metals (Tamura et al 1995). In our case the core hole decreases the L3 Experimental and theoretical XANES spectra of Ag20 at the Ag L1 edge.…”

“…For a selfconsistent potential, this improves the agreement with the experiment, while for a non-selfconsistent potential the decrease in white line intensity is too large. We can recall that in semiconducting Cu20 the inclusion of the core hole increases the white line intensity (Grioni et al 1992), contrary to transition metals where it decreases the L3 white line (Tamura et al 1995). Hence one could suggest that the fully relaxed and screened model applied in this study overestimates the screening in the case of a non-selfconsistent potential, being suitable rather to metals than to semiconductors.…”

Subsurface Oxygen in Oxide-Derived Copper Electrocatalysts for Carbon Dioxide Reduction

“…Figure 3a shows the oxidized sample with an EELS signature resembling that of Cu 2 O. [38][39][40] Experimental details were 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 slightly different between EELS and APXPS (nanoparticles versus foil and lower pH in EELS), resulting in Cu 2 O being the dominant species in EELS. After reduction, two chemically different oxygen species were found: one inside the catalyst, assignable to subsurface oxygen (b) and one in a precipitate on the surface of the catalyst (c).…”