AI Article Synopsis
- The FCC lattice of porous Cu, made by dealloying AlCu, has a high concentration of twinning defects, averaging 3 nm in size along the ⟨111⟩ directions.
- The presence of these twinning defects was confirmed through X-ray diffraction, revealing a 5% chance of their formation, but most disappeared when the material was annealed at 873 K for 24 hours.
- Twinned Cu oxidizes more quickly than non-twinned Cu, with DFT calculations indicating that these defects serve as nucleation centers for CuO growth due to favorable geometries on the twinned surfaces.
Article Abstract
The fcc lattice of porous Cu prepared by dealloying AlCu with HCl aqueous solution exhibits a high density of twinning defects with an average domain size of about 3 nm along the ⟨111⟩ directions. The high density of twinning was verified by X-ray diffraction and qualitatively interpreted by a structural model showing the 5% probability of twinning defect formation. Most of the twinning defects disappeared after annealing at 873 K for 24 h. Twinned Cu reveals much faster oxidation rate in comparison to that without (or with much fewer) twinning defects, as shown by X-ray diffraction and hydrogen differential scanning calorimetry. Using ab initio DFT calculations, we demonstrate that twinning defects in porous Cu are able to form nucleation centers for the growth of CuO. The geometry of the V-shaped edges on the twinned {211} surfaces is favorable for formation of the basic structural elements of CuO. The fast oxidation of porous Cu prepared by dealloying can thus be explained by the fast formation of the CuO nucleation centers and their high density.
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| http://dx.doi.org/10.1021/acs.inorgchem.7b03225 | DOI Listing |
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