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Layered Double Hydroxides Containing Intercalated Zinc Sulfide Nanoparticles: Synthesis and Characterization
Author(s) -
Wu Guoqing,
Wang Lianying,
Evans David G.,
Duan Xue
Publication year - 2006
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200600203
Subject(s) - chemistry , sphalerite , zinc , layered double hydroxides , thermogravimetry , thermal decomposition , inorganic chemistry , nanoparticle , thermal stability , differential thermal analysis , thermal analysis , powder diffraction , fourier transform infrared spectroscopy , crystallography , nuclear chemistry , hydroxide , chemical engineering , mineralogy , diffraction , organic chemistry , thermal , pyrite , physics , optics , meteorology , engineering
Abstract Nanosized ZnS has been synthesized in the interlayer galleries of Mg–Al layered double hydroxides (LDHs) by a process involving ion exchange of a Mg 2 Al‐NO 3 LDH precursor with a zinc–citrate complex {Na 2 [Zn(C 6 H 4 O 7 )] · 3 H 2 O} followed by reaction between the intercalated [Zn(C 6 H 4 O 7 )] 2– anions and H 2 S. The materials have been characterized by elemental analysis, powder X‐ray diffraction (XRD), transmission electron microscopy, FTIR spectroscopy, MAS 13 C NMR spectroscopy, and UV/Vis diffuse reflectance spectroscopy, and structural models have been proposed. The XRD diffraction patterns indicate that the layered structure is maintained and that the basal spacing in the intercalated materials depends on the orientation of the citrate moiety. The results confirm that cubic ZnS (sphalerite) is formed in the interlamellar domain rather than on the external surfaces and is co‐intercalated with citrate dianions. The growth of ZnS particles is constrained by the layers of the LDH resulting in a large blue shift in the bandgap compared with the bulk material. The thermal decomposition process of the hybrid material has been characterized by in situ high‐temperature powder XRD and thermogravimetry‐differential thermal analysis (TG/DTA) coupled with mass spectrometry. The thermal stability of the zinc–citrate complex anions intercalated in LDHs is lower than that in the sodium salt. Thermal treatment below 270 °C leads to a reorientation of the citrate anions in the interlayer galleries associated with a significant interlayer contraction. No obvious changes in the XRD peaks corresponding to ZnS are apparent below 400 °C, indicating that sintering to form larger particles is successfully inhibited by the layered host; at higher temperatures the ZnS is oxidized with evolution of SO 2 . (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)