The Fabrication Of Semiconductor Catalyst Doped By Noble Metal And Its Application On The Reactive Dye Degradation

Smiconductor-based photocatalysts is a technology of catalyst activation actuated by light atroom temperature, using redox reaction of vacancies and photoelectrons to deacidize the metalions and decompose the organism. Moreover, the technology has been widely applied in the fieldof antisepsis, sterilization, hydrogen production and effluent treatment. The typical metal lack ofp type semiconductor like cobalt oxide (Co3O4，Eg=1.5eV) and narrow-band semiconductorlike cuprous oxide (Cu2O，Eg=2.2eV) have been considered as the promising photocatalystsbesides TiO2because they can be easily activated by visible light from solar energy. Due to thehigher recombination rate of photogenerated electrons and holes, pure semiconductor shows alower quantum efficiency.In this paper, Co3O4nanosheets were synthetized through the hydrothermal method and hotsolvent method. Moreover, silver mirror reaction was used to dop Ag nanoparticles on Co3O4surface at room temperature. The performance of the photocatalysis was evaluated bydegradation of rhodamine B (RB) under visible light. The surface features, microstructure andoptical property of the nanosized Ag/Co3O4composites were characterized and analyzed byscanning electron microscope (SEM), transmission electron microscope (TEM), X-raydiffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-vis spectroscopy (UV-Vis).Experimental data suggested that the Co3O4doped with Ag nanoparticle (average diameters of10~15nm) owned lower band gap energy and photoluminescent (PL) intensity. Meanwhile, theAg/Co3O4exhibited high stability and excellent dispersion property in dye solution. Compared topure Co3O4, Ag Co3O4nanocomposite exhibited a higher ability of photocatalysis in thedegradation of the5mg·L-1RhB solution and15mg·L-1MB solution. Meanwhile, the effect ofthe doped quantity of Ag nanoparticles on the catalytic activity of composite catalysts was alsoexplored. It should be noted that3.06%Ag doped Co3O4exhibited the highest catalytic activityin visible light region. On the other side, Au/Cu2O/Pd and Pd/Cu2O/Pd three-layer composite structures werefabricated. X-ray diffraction (XRD), scanning electron microscope (SEM) and energy-dispersivespectrometry (EDS) were applied to characterize the physical features and structure of the gainedsamples. The average diameter of sandwich profile was about120nm, and this compoundnanoparticle exhibited a high catalytic activity for the degradation of methyl orang (MO) undervisible light.