Preparation And Application Of Tin-molybdenum Composite Metal Oxide

Semiconductor materials SnO₂ and MoO₃ have attracted much attention due to their wide applications,such as photocatalysis,gas sensors and capacitor materials.In this paper,SnO₂/MoO_3-x-x composites with heterojunction structure,sandwich morphology and self-doping Mo⁵⁺were successfully synthesized by sol-gel method.SnO₂/MoO_3-x-x composite material was explored in photocatalysis,antibacterial application and anode for lithium-ion battery.Higher removal rate of organic dyes,long-term uncontaminated medium,and improvement of charge/discharge performance than intrinsic semiconductors SnO₂ and MoO₃ were obtained.Detailed work and results are as follows:1.Synthesis of SnO₂/MoO_3-xTin dichloride?SnCl₂?and ammonium molybdate(?NH₄?₆Mo₇O₂₄)were used as raw materials for synthesis.The composite material SnO₂/MoO_3-x-x was prepared by sol-gel and electrostatic self-assembly methods calcined at 450?.The morphology,scale,structure and elemental composition of the composites SnO₂/MoO_3-x-x were obtained by XRD?X-ray diffraction?,TEM?Transmission electron microscopy?and XPS?X-ray photoelectron spectroscopy?.Under electron microscopy,15 nm SnO₂ particles were embedded between MoO_3-x-x nanosheets,which made SnO₂/MoO_3-x-x presents the novel sandwich morphology.Self-doped Mo⁵⁺and oxygen holes were successfully introduced into SnO₂/MoO_3-x-x composite system,and the distribution ratio of Mo⁵⁺and Mo⁶⁺was 90.66%:9.34%.In addition,the appropriate internal electric field was formed by SnO₂ and MoO_3-x-x due to their special heterojunction structure,which controlled the movement of carriers and realized the efficient separation of electron-hole pairs.2.Photocatalyst SnO₂/MoO_3-xUV-Vis DRS?Ultraviolet-visible diffuse reflectance spectra?shows that SnO₂/MoO_3-x-x catalysts exhibit strong light absorption properties in the range of 400-800 nm compared with intrinsic semiconductors SnO₂ and MoO₃.In addition,the characterization of FL?Fluorescence spectrum?also shows the large carrier density and good separation in the catalyst.Methylene blue?MB?and Rhodamine B?RHB?were degraded rapidly under visible light irradiation by photocatalyst SnO₂/MoO_3-x-x and reached high removal rate98.7%and 81.2%in 7 hours,respectively.The degradation in acidic conditions?pH=4?is more success than in neutral or in alkaline environment.In addition,SnO₂/MoO_3-x-x still retains perfect activity after 5 cycles.3.Battery anode materialsThe anode materials SnO₂,MoO₃ and SnO₂/MoO_3-x-x were assembled into lithium-ion batteries and the performance test of batteries showed that the capacity retention rate of SnO₂/MoO_3-x-x was about 50%in five cycles of charge-discharge cycle.The capacity of SnO₂/MoO_3-x-x was higher than that of SnO₂ and MoO₃ at high rate of 1000 mA·g^-1.EIS spectrum showed that SnO₂/MoO_3-x-x had lower barriers to the transmission of Li ions.4.High-performance antibacterial material SnO₂/MoO_3-xThe moulds have no obvious growth and reproductive capacity and SnO₂/MoO_3-x-x shows perfect antibacterial activity in the culture medium mixed with the antibacterial component SnO₂/MoO_3-x-x in the bright environment during the antibacterial experiments nearly one month.Interestingly,it can also inhibit the growth of moulds in the absence of light.In addition,the antimicrobial properties of SnO₂/MoO_3-x-x in the absence of light were better explained with the theoretical support of the surface plasmon resonance?SPR?properties of molybdenum trioxide.Therefore,the antimicrobial activity of SnO₂/MoO_3-x-x is also the result of the synergistic effect of photocatalysis and surface plasmon resonance.