Publication Date:
2017-05-12
Description:
The X-ray diffraction (XRD) pattern of a deleterious phase in the photocatalyst based on Cd1 − xZnxS/Zn(OH)2contains two relatively intense asymmetric peaks withd-spacings of 2.72 and 1.56 Å. Very small diffraction peaks with interplanar distances of (d) ≃ 8.01, 5.40, 4.09, 3.15, 2.49 and 1.35 Å are characteristic of this phase but not always observed. To identify this phase, the XRD patterns for sheet-like hydroxide β-Zn(OH)2and sheet-like hydrozincite Zn5(CO3)2(OH)6as well as for turbostratic hydrozincite were simulated. It is shown that the XRD pattern calculated on the basis of the last model gives the best correspondence with experimental data. Distances between layers in the turbostratically disordered hydrozincite fluctuate aroundd≃ 8.01 Å. This average layer-to-layer distance is significantly higher than the interlayer distance 6.77 Å in the ordered Zn5(CO3)2(OH)6probably due to a deficiency of CO32−anions, excess OH−and the presence of water molecules in the interlayers. It is shown by variable-temperature XRD and thermogravimetric analysis (TGA) that the nanocrystalline turbostratic nonstoichiometric hydrozincite-like phase is quite thermostable. It decomposes into ZnO in air above 473 K.
Print ISSN:
2052-5192
Electronic ISSN:
2052-5206
Topics:
Chemistry and Pharmacology
,
Geosciences
,
Physics
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