Synthesis And Properties Of Sn-based Micro/nano Crystals

Monodisperse ZnSn（OH）₆（ZHS） microcrystallites （MCs） with two morphologieshave been prepared through a facile preparation method without complicated steps,or advanced experimental conditions or equipment. MSn（OH）₆（M=Mg, Cu, Mn, Cd）made of5-10nm nano-crystals were obtained through a general synthesis underthe common temperature and atmosphere. The heterostructure N2SnO4/SnO₂（N=Zn, Mg, Mn） and CuO/SnO₂were achieved by calcining ZnSn（OH）₆and MSn（OH）₆（M=Mg, Cu, Mn）under atmosphere and nitrogen with the same warming and reducingtemperature. The structures and properties of as-prepared products were thoroughlycharacterized using X-ray photoelectron spectroscopy （XPS）, scanning electronmicroscope （SEM）, transmission electron microscope （TEM）, high-resolutiontransmission electron microscope （HRTEM）, UV-Vis spectra, electron paramagneticresonance （EPR）, and X-ray diffraction （XRD）, respectively. The results aresummarized as follows:1. Monodisperse ZnSn（OH）₆（ZHS） microcrystallites （MCs） with twomorphologies have been prepared through a facile preparation method withoutcomplicated steps, advanced experimental conditions or equipment. The morphologyand compositional characteristics of the3D hierarchitectures （HAs） of ZHS MCs wereinvestigated by various techniques. In the reaction system the morphology evolutionfrom cube to sphere was controlled with adding different concentration of NH4OH.Meanwhile, the formation mechanisms of the two ZHS MCs were studied via a seriesof time-dependent experiments. Interesting, ZHS MCs were self-assembled from theirregular-shaped nanoparticles （5¹0nm）. The gas sensor performance influencessuch as oxygen vacancies defects, effective surface area and band gap energy. The gas sensors based on ZHS presented a good sensor performance to HCHO. However,The gas sensors based on of ZHS spherical MCs exhibited the higher sensitivity,shorter recovery time and good reproducibility to HCHO than those of ZHS cube MCs.More importantly, the best gas-sensing properties were found coming from the⁶00nm spherical ZHS MCs owing to more oxygen vacancies defects, less band gap energy,and larger active surface area. ZnSn（OH）6crystal materials could be candidates of gassensitive materials.2. The preparation of MSn（OH）6（M=Mg, Cu, Mn and Cd） made of5-10nmnanocrystals at room temperature in the standard atomosphere. The detail cellstructure was analysed by XRD data. The information of MSn（OH）6（M=Mg, Cu, Mnand Cd） nanocrystals about the morphology, particle size and surface us achieved byFESEM and TEM images. The results show that the materials are large scale obtainedand made of5-10nm nano crystals. The particles are very good dispersancy.Corresponding gas-sensing data show that the gas sensor based on the same size ofthese compounds, CdSn（OH）6shows the best gas sensitive performance. MSn（OH）6nanocrystallines are also an ideal kind of candidate for gas sensitive material.MnSn（OH）6crystal materials could also be candidates of gas sensitive materials.3. According to the above method for the preparation of ZnSn（OH）6andMSn（OH）6（M=Mg, Cu, Mn） in air and nitrogen atmosphere, under differentcalcination temperature. Through XRD data analysis, the phase structures of theproduct under different calcination temperature are not the same, just startinggenerating NSnO3（N=Zn, Mg, Mn）, N2SnO4and SnO2, with temperature increasing,but the final products change into N2SnO4（N=Zn, Mg, Mn） and SnO2heterostructures. Notably, CuSn（OH）6as the reaction of calcining temperature,different product phase is only CuO and SnO2, but its calcination morphologychanged dramatically. ZnSn（OH）6by solid cubic crystals into a hollow cube crystal,and MgSn（OH）6and MnSn（OH）6together is more serious. Through battery test, it isbroaden the material type of battery application.