Fabrication And Photocatalytic Properties Of The Cu And CuS Hollow Microspheres

Due to the special structure, the hollow spheres have hugeapplications in drug delivery, catalytic and photoelectric area. Thefabrication and application of Cu and CuS hollow spheres have attractedmuch attention because of the special characteristics of physical andchemical.In this paper, the Cu and CuS hollow ultra-fine spheres werefabricated by two-step liquid reduction method and microemulsion-template-interfacial-reaction route separately. And the photocatalyticperformances of these two hollow spheres were also studied. The maincontents and the conclusions are as follows:（1） We took a two-step liquid reduction method for fabricating hollowCu ultra-fine spheres, in which Cu₂O microspheres were used as thesacrificial templates as well as the reagent to provide Cu+during thereaction process and hydrazine hydrate was used as the reductant.（2） Studied the pre-reduction process of glucose and the furtherreduction process of hydrazine hydrate, the conclusions can be got asfollows:1) compared with direct reduction method, the two-step liquidreduction method can greatly improve the uniformity of the particle size.2)In the process of pre-reduction, the reaction temperature, the concentrationof NaOH and glucose solutions all contributed a great impact on themorphology and size of the Cu₂O prepared. The best condition of theprocess is: the reaction temperature was30℃, the concentration of NaOHsolution was3mol/L, the concentration of glucose solution was2.5mol/L.3) Allylthiourea acted as a complexing agent in the second reductionprocess. When the amount of allylthiourea was3mL（1g/L）, the mostregular Cu hollow microspheres can be developed.（3） The study of the mechanism of the formation of Cu hollowspheres showed that: allylthiourea and Cu（I）could form complex ion [Cu_x（ATU）_y]ⁿ⁺. When the amount of allylthiourea is sufficient, the complexion can form a protective layer on the surface of the precursor and help tokeep its spherical shape. The decomposed Cu₂O nanoparticles supply alarge amount of Cu+to the solution. Then, the inner side of the Cu₂Ogradually decompose and the reduced metal Cu will deposit on the surfaceof the spherical Cu₂O. Then, the hollow structures of Cu are fabricated.（4） The study of the reaction conditions and mechanism of thepreparation of CuS hollow spheres showed that: the Microemulsion dropletwas used as a template to obtain the hollow spheres. The reactiontemperature and the amount of copper naphthenate, which can control thegrowth of the nuclei on the oil/water interface, are the important factors forforming hollow spheres. The average diameter of the CuS hollow spherescan be adjusted from110to280nm by changing the content of oil phase.（5） At last, the photocatalytic performances of hollow ultra-finecopper powders and CuS hollow spheres were studied. It showed that,under the light of xenon lamp for60min, the degradation rates ofmethylene blue （MB） both could be90%and above in the presence of Cuand CuS hollow spheres, which were much higher than that only in thepresence of irregular Cu particles or CuS solid spheres.