Fabrication Of Metal Oxides Based Catalytic Micromotors For Environmental Application

Artificial micro-nano motors can generally be driven by energy such as chemical fuel or external stimuli such as light,ultrasound,magnetic fields,etc.,which can effectively convert different energy into mechanical energy for autonomous movement,and are widely used in drug delivery,sensing,bacterial separation,and environment.Motors that driven by hydrogen peroxide are the most widely used,but most of them use precious metals?Pt,Au,etc.?as catalysts,leading to autonomous propulsion.Not only is it expensive,but for practical applications,it greatly limits its need for mass production.To a certain extent,it limits a wide range of commercial applications.Secondly,the current motor has some challenges,such as complex manufacturing process,low catalytic efficiency,poor biocompatibility and unfriendly to the environment.Finally,the controllable motor movement has become an important research direction.Whether in bio-targeted drug loading or environmental remediation,there are certain requirements for the magnetic properties of the motor.Therefore,exploring motors with low cost,simple preparation methods,and environmentally friendly motors has become a research hotspot,laying a foundation for future practical applications.Here,in response to the above problems that need to be solved,we have launched two main tasks:1.By annealing Prussian blue?PB? at different temperatures,an environmentally friendly iron oxide?Fe₂O₃? micromotor was obtained,and the Fe₂O₃ micromotor was applied to adsorb organic pollutants to achieve the purpose of sewage treatment.Fe₂O₃ can effectively catalyze the production of hydrogen peroxide?H₂O₂?to produce O₂,thereby forming a driving force that allows the Fe₂O₃ micromotor to continue to move.The composition of PB and Fe₂O₃ micromotors was analyzed by X-ray diffraction?XRD?and Raman spectroscopy?Raman?,proving the successful synthesis of micromotors.Scanning electron microscope?SEM?and transmission electron microscope?TEM?were used to characterize the micro-morphology of PB and Fe₂O₃ micromotors,and element distribution diagram?EDS?was used to show that Fe and O elements were evenly distributed on the surface of micromotors.The valence state before and after annealing of PB was analyzed by X-ray photoelectron spectroscopy?XPS?.It is worth mentioning that the life of the micromotor can be as long as 2 hours in 7% H₂O₂solution.In the experiment of absorbing methyl blue,the Fe₂O₃ micromotor can effectively adsorb pollutants within five minutes,and due to the presence of-Fe₂O₃,the micromotor can be recovered by the external magnetic field after adsorbing pollutants,avoiding the environmental secondary pollution.2.Fe-MOF was prepared by hydrothermal method,and then Fe-MOF derivative carbon-based micromotor was obtained by annealing Fe-MOF.After a simple carbonization process,the motor not only has excellent catalytic performance,it can effectively catalyze hydrogen peroxide and decompose into oxygen to provide power for the motor's autonomous movement.In addition,the motor is also magnetic,and it can accurately control the direction of the motor's movement through the external magnetic field without any surface modification.The morphology of the Fe-MOF derivative carbon-based micromotor was characterized by SEM and TEM.The composition of Fe-MOF before and after carbonization was analyzed by XRD,Raman and EDX.Observe the movement of the micromotor under different hydrogen peroxide concentrations through a microscope.Its speed can reach 82?m s^-1 in 10%H₂O₂ solution.After introducing the external magnetic field,the influence of the magnetic field on the movement of the micromotor was explored.