| Three-dimensionally ordered macroporous(3DOM)particles have unique properties such as three-dimensional ordered structure,high porosity,large specific surface area,few defects,excellent conductivity,and easy chemical modification of the surface.They have very important application value in the fields of catalysis,adsorption,sensing,and battery.However,due to the limitations of the current preparation technology and methods,it is still difficult to achieve high-throughput preparation and recycling of 3DOM particles,thereby limiting their widespread use.This study mainly applied microfluidic droplets and reverse colloidal crystal template technologies to high-throughput preparation and simple recovery of magnetic three-dimensional ordered(M3DOM)conductive particles.Relationship between the structure and the electrochemical performance of the particles was also investigated by using electrochemical methods.The specific research contents are as follows:1.A simple microfluidic droplet device was quickly fabricated to high-throughput preparation of silica colloidal crystal microspheres by using commercial micro-pipes.Firstly,monodisperse silica colloidal nanoparticles with particle sizes of 132,250,462,572 and 629 nm were synthesized,respectively.Secondly,two kinds of microfluidic droplet devices were fabricated: coflow and coaxial devices.with coaxial and flow focusing structures;Then,the silica colloidal dispersion with weight to volum ratio of 20% was used to fabricate uniform sized microdroplets by the droplet microfluidic device.An online heating and stirring method was proposed to self-assemble the nanoparticles in the droplets to form a 3DOM colloidal crystal structure.Finally,colloidal crystal microspheres were high-throughput produced by changing the device and adjusting the flow rate of the internal and external two-phase liquids in the size ranging from a few microns to a few hundred microns.2.Uniform sized M3 DOM conductive particles were simply prepared by using the colloidal crystals as reverse templates.Ethanol precursor which contains ferric nitrate nonahydrate and furfuryl alcohol was filled into the interstitial spaces of colloidal crystal microspheres by impregnation method.After vacuum filtration and drying,the precursor was polymerized for 12 h at 80 ?.Then,the particles were calcined in a tube furnace at 750 ? under N2 protection for 4 h.Finally,the conductive M3 DOM particles were obtained by removing the template silicone nanoparticles.The structure of the particles was characterized by using scanning electron microscopy.The conductive M3 DOM carbon particles with various sizes and structures were prepared by adjusting the structure of colloidal crystal microspheres.3.Investigation of the relationship between the structure the conductive M3 DOM particles and their electrochemical performance.Electrochemical methods such as cyclic voltammetry and AC impedance were mainly used to study the electrochemical performance of the particles.The results show that the particles was not suitable for the diffusion-controlled reaction processes because of the serious overlap of the diffusion layer.However,for adsorption-controlled processes,the obtained signals were increased with decreasing of the pore size of the particles.By comparison with other structured particles,it was found that M3 DOM particles with a pore size of 132 nm are more suitable for electrochemical applications.In summary,colloidal crystal microspheres were simply prepared by using microfluidic droplet and online heating methods,and used as reverse templates for fabrication of conductive M3 DOM particles.By reversely replicating colloidal crystal templates,high-throughput preparation of magnetic three-dimensional ordered macroporous conductive particles was achieved.The M3 DOM particles can be used as a good material of the electrode for electrochemical applications in the files of batteries,capacitors,and sensors. |
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