Electrochemical Synthesis, Characterization And Influencing Factors Of Micro-/nano-Materials Including Te Element

As transition-metal chalcogenides semiconductors, telluride andcopper telluride micro/nanomaterials have become hot researches inmaterials science due to its potential applications in the fields of catalysis,optoelectronic conversion, piezoelectronics, thermoelectronics, gassensing. To date, a series of telluride and metal telluridemicro/nanomaterials have been successfully prepared by many groupsthrough various approaches. However, some shortcomings can be foundin the aforementioned methods to fabricate featherlike Te and coppertelluride, including use of organic reagents，slow growth rate, highreaction temperature, long reaction time and complex process.In this thesis, we designed a simple, fast, energy-efficientelectrodeposition route to successfully synthesize feather-like t-Te andmetal telluride micro/nanomaterials with different morphologies. Thephase and morphology of the as-prepared products were characterized bymeans of powder X-ray diffraction （XRD）, energy dispersivespectrometer （EDS）,（high resolution） transmission electron microscopy（HR/TEM）, selected area electron pattern （SAED） and scanning electronmicroscopy （SEM）. Some factors influencing the formation of theproducts, such as the initial amount of reactants, complexing agents,surfactants, deposition current or voltage, were systematicallyinvestigated. The time-dependent shape-evolution process of the productswas observed. The main contents are summarized as follows:1. Feather-like t-Te was synthesized via a facile galvanostaticelectrodeposition route in air at room temperature, employing Na₂TeO₃and diluted HNO₃as the starting materials, employing the depositioncurrent of8mA for5min. Experiments showed that the morphology ofthe final product could be markedly affected deposition time. Moreover,diluted HNO₃was indispensable in the formation of featherlike t-Temicrostructures. 2. Nanoparticles-strewn undergrowth-like Cu₇Te₄superstructures（NUCTSs） have been successfully synthesized in a nitric acid solution viaa simple galvanostatic deposition method at room temperature,employing Na₂TeO₃as the Te^2-ion source, Cu plate （11cm2） as theworking electrode and the coppper ion source under the assistances ofsodium dodecyl benzene sulfonate （SDBS） and tartaric acid. Some factorsinfluencing the formation of NUCTSs were systematically investigated,including the depositing current, the original amounts of reactants,complexing agents, deposition current. Experiments showed that dilutedHNO₃was indispensable in the formation of NUCTSs. A time-dependentshape evolution illustrated that the formation of NUCTSs underwent aself-assembly process of nanoparticles under the assistances of additives.Furthermore, the as-obtained NUCTSs could promote the oxidation ofhydrazine and exhibited weak linear current-voltage （I-V） characteristics.3. Cu₇Te₄nanorod arrays were successfully prepared by a simplegalvanostatic deposition route, employing Na₂TeO₃and dilluted HNO3asthe reactants in the presence of sodium dodecyl benzene sulfonate （SDBS）in air at room temperature. Cu₇Te₄nanorod arrays were deposited at thecurrent of16mA for5min. Results showed that SDBS and HNO3weretwo indispensable factors in the formation of nanorod arrays. It was foundthat the as-obtained Cu₇Te₄arrays could promote the electrochemicaloxidation of hydrazine and exhibit good photoconductivity.