Cover Picture: Fe‐Doped ZnO Nanoparticles: The Oxidation Number and Local Charge on Iron, Studied by ⁵⁷Fe Mößbauer Spectroscopy and DFT Calculations (Chem. Eur. J. 10/2013)

Abstract

If produced by flame spray pyrolysis, more than 10% of Fe dopants can be introduced into the wurtzite lattice of ZnO nanoparticles. A combined experimental and theoretical Mößbauer spectroscopy study unambiguously assigns the Fe dopants as substitutional FeII ions, although the charge‐dependent properties of the Fe dopants in ZnO are similar to those of Fe3+ ions. For more information see the Communication by T. Heine et al. on

Redox Activity and Nano–Bio Interactions Determine the Skin Injury Potential of Co3O4-Based Metal Oxide Nanoparticles toward Zebrafish

“…Doping a Co 3 O 4 matrix with transition metals such as Fe, Cr, Mn, and Cu induces trap levels within/beyond the conduction and valence band. − These levels allow electron flow across the interface depending on the nature of the space charge layer created due to mismatch of the charges at the interface . The two absorption edges of Fe-doped Co 3 O 4 at ∼708 (L 3 ) and 721 (L 2 ) eV with a 13 eV coupling constant show characteristic signals of Fe 3+ due to charge-transfer transition between the Fe 3+ d-electrons and the conduction or valence band of Co 3 O 4 . , Similarly, the two Cr edges occurring at 575 (L 3 ) and 584 (L 2 ) eV with 8 eV are the characteristic signal for Cr 3+ d - electron transition. The weak Cu edge was observed at 931 (L 3 ) and 951 (L 2 ) eV, characteristic of a Cu 2+ d-electron transition.…”