| In this thesis, our work mainly focused on the solution-based "bottom-up" method to synthesize special morphological and structured IV-VI compounds with excellent properties. The ultrathin SnO2 nanosheets were synthesized by one-pot hydrothermal method, after having been investigated by various measurements, the "Oriented Attachment" mechanism was used to illustrate the morphology evolution. By applying this material in lithium ion battery, higher lithium storage was obtained compared to the other counterparts. Besides, novel room-temperature ferromagnetism was found in the products of SnO2 nanosheets, which was proposed to be the result of surface Sn vacancies. The SnS2 nanosheets were fabricated using similar protocols, and these products features splendid photocatalytic capability towards organic pigments. Finally, we synthesized Au hollow cubic shells with uniform size and morphology using an improved microemulsion method and a subsequent deposition-precipitation process. The main results are summarized as follows.(1) Successfully synthesized large-scale and highly pure ultrathin SnO2 nanosheets (NSs), with a minimum thickness in the regime of ca.2.1 nm as determined by HRTEM; and in good agreement with XRD refinements and AFM height profiles. Through TEM and HRTEM observations on time-dependent samples, we found that the as-prepared SnO2 NSs were assembled by "oriented attachment" of pre-formed SnO2 nanoparticles (NPs). Systematic trials showed that well-defined ultrathin SnO2 NSs could only be obtained under appropriate reaction time, solvent, additive, precursor concentration and cooling rate. A certain degree of nonstoichiometry appears inevitable in the well-defined SnO2 NSs sample. However, deviations from the optimal synthetic parameters give rise to severe nonstoichiometry in the products, resulting in the formation of Sn3O4 or SnO. This finding may open new accesses to the fundamental investigations of tin oxides as well as their inter-transition processes. Finally, we investigated the lithium-ion storage of the SnO2 NSs as compared to SnO2 hollow spheres and NPs. The results showed superior performance of SnO2 NSs sample over its two counterparts. This greatly enhanced Li-ion storage capability of SnO2 NSs is probably resulting from the ultrathin thicknesses and the unique porous structures:the nanometer-sized networks provide negligible diffusion times of ions thus faster phase transitions; while the "breathable" interior porous structure can effectively buffer the drastic volume changes during lithiation and delithiation reactions.(2) Room-temperature ferromagnetism of ultrathin SnO2 nanosheets has been found experimentally with saturation magnetization and coercive force of about 15.1 memu/g and 20 Oe, respectively. First-principles calculations reveal that oxygen atoms at O-terminated surface in SnO2 sheet are spin polarized, resulting in magnetic moment of 1.6μB for pure SnO2 nanosheet while Sn atoms just beneath the O-terminated surface contribute only-0.082/μB Besides, we have systematically studied the magnetic behavior of post-annealed SnO2 NSs samples by treating at different temperatures from 200℃to 400℃and under O2 or Ar atmosphere. Room-temperature ferromagnetisms have been observed in all studied samples. It is found that the saturation magnetization of all the annealed samples do not feature mono-dependence on oxygen vacancies, whereas the Sn vacancy-related origin seems more plausible to account for variations in magnetization of samples studied. This finding is quite correspondent to first-principle calculation results from our previous work. Furthermore, the Curie temperature of SnO2 nanosheets was estimated to be around 350℃rendering it a very good option for next-generation of spintronics.(3) Successfully synthesized SnS2 nanosheets with high purity and large production, the thicknesses of which are about 5 nm. Afterwards, we systematically studied the influences on the morphologies of final products brought by the polarity of the solvent. Furthermore, by comparing the performances of different SnS2 samples on the degradation of methylene blue, the effect of different morphologies and crystallinities were discussed in detail. The results enclosed that the hexagonal SnS2 nanosheets possessed better photocatalytic property compared to hierarchical SnS2 microspheres or even TiO2 (P25), which is meaningful in the water treatment.(4) Successfully synthesized gold-coated GeO2 nanocubes by applying surface functionalization and deposition-precipitation methods. The effect of gold salt concentration on the size distribution and dispersion of gold nanoparticles are examined. It was found that homogeneous and well-dispersed gold nanoparticles on GeO2 nanocubes could be obtained only if gold salt is abundant to favor simultaneous, homogeneous nucleation of gold. Eventually, additional gold was reduced onto these attached "seed" particles accompanied by synchronous dissolution of GeO2 cores, resulting in gold hollow cubic shells. This is an easy, convenient and in-situ method for preparation of gold hollow cubic shells. The absorption spectra of obtained samples have been explained according to the structures of samples. Gold hollow cubic shells feature a plasmon resonance peak at above 900 nm, which makes it very attractive in biochemical applications.
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