Synthesis Of The TiO₂@Carbon Microsphere Light-driven Micromotor And Performance Research

Micromotor is a kind of particle or structure that can convert external energy（light,sound,magnetism,electricity,chemical energy,etc.）into kinetic energy to achieve autonomous movement and its size is micro-nano scale.With the development of science and technology,scientists have been exploring the synthesis technology of micro/nano materials,and micromotor have been developed rapidly in structure construction,driving mode,behavior regulation and speed.This makes micromotor have great application potential in biomedicine,environmental governance and other areas.In this paper,titanium dioxide（TiO₂）light-driven micromotor was prepared by using carbon microspheres（CMS）as template.Based on the systematic characterization of its morphology,composition and structure,we investigate its light-driven performance and mechanism,and explore the degradation performance and mechanism of organic dye molecules.The conclusions are as follows:（1）The CMS with good dispersibility and uniform size was synthesized by hydrothermal method under controlled reaction condition.Using CMS as a template,TiO₂@CMS spherical core-shell micromotor was obtained by loading TiO₂ on its surface through three different methods.Under UV irradiation and in H₂O₂ solution,the micromotor is self-driven by decomposing H₂O₂ to generate O₂ bubbles,and the maximum speed can reach 44.6μm/s.Then,in the experiment of adsorption and degradation of organic dye Rh B,the degradation rate can reach 99%after 60 min.The adsorption kinetic model shows that the adsorption and degradation of Rh B by TiO₂@CMS core-shell micromotor follows the quasi-second-order kinetic equation.（2）The hollow TiO₂ light-driven micromotor was fabricated by removing the internal carbon template through heat treatment.And it can achieve repid motion under the irradiation of ultraviolet light in a low-concentration H₂O₂ solution,the movement speed of the hollow TiO₂ micromotor can reach 14.95 um/s under the concentration of 1%H₂O₂ solution.The degradation rate of Rh B by the micromotor was as high as 98%after10 min,which was due to the combined effects of the photocatalytic effect of the hollow TiO₂ layer,the micro-stirring effect generated by the bubble movement induced by photocatalysis,and the free radical effect generated by the decomposition of H₂O₂.Compared with the solid core-shell structure,its degradation speed is obviously improved.The micromotor can be recycled and reused by loading a certain amount of magnetic Fe₃O₄ on the surface of the hollow TiO₂ micromotor.In the repeated degradation experiments of organic dyes,the degradation rate of Rh B by TiO₂/Fe₃O₄ hollow micromotor still have 85%after three cycles.In summary,the spherical TiO₂ light-driven micromotor was prepared by sol-gel method with CMS as the template,without the use of electrochemical workstation,sputtering apparatus and other complex equipment.And this method has the advantages of low cost,simple operation,strong versatility and batch preparation.The prepared micromotor has the advantages of high speed,rapid response to ultraviolet light and high degradation efficiency,and has important significance for expanding the practical application of the TiO₂ light-driven micromotor and developing efficient and intelligent micromotor for environmental governance.