Photoelectric Response And Photocatalytic Property Of Ag Modified Carbon-doped TiO₂

As a kind of ideal semiconductor photocatalytic material,TiO₂ has many advantages: chemical stability,non-poisonous,inexpensive and so on.The wide band gap of TiO₂,which restricts the light response range in the UV region,greatly limits the photochemical conversion efficiency of solar energy.The elemental doping is one of the effective methods to narrow the band gap of TiO₂.Furthermore,the high recombination rate of electron-hole pairs of TiO₂ also restricts its photoelectric response and photocatalytic properties,and precious metal deposition on the surface of TiO₂ can be used to solve the problem.In this paper,TiO₂ photocatalytic material with improved photoelectric response and photocatalytic properties was prepared by using thermal oxidation,electrophoretic deposition and photo-reduction deposition method.The surface morphology,composition and structure of the samples were tested by scanning electron microscopy?SEM?,energy-dispersive X-ray spectroscopy?EDS?and X-ray diffractometry?XRD?.The photoelectric response,photocatalytic properties and the related mechanism of the TiO₂ photocatalytic materials were investigated by measuring the transient photocurrent density,photocatalyticdegradation rate of RhB,UV-Vis and fluorescence spectrum.The main works are as follows:?1?With TiC as raw material,cardon-doped TiO₂?C-TiO₂?was prepared by thermal oxidation and electrophoretic deposition.The C-TiO₂ samples perpared in the oxidation temperature range of 550-650 ? were composed of anatase and rutile phase.When the temperature was above 700 ?,the anatase phase converted into rutile phase completely.The C-TiO₂ photocatalytic materials prepared at different temperatures all showed obvious photoelectric response and photocatalytic property in visible light region,especially for the sample formed at 650 ?.?2?In order to improve the photoelectric response and photocatalytic properties of C-Ti O₂,Ag nanoparticles were deposited on the surface of C-Ti O₂?Ag-C-Ti O₂?by photoreduction deposition in Ag NO3 solution with different concentrations.It has been shown that the photoelectric response and photocatalytic properties of C-Ti O₂ can be significantly improved by Ag deposition.Concentration of Ag NO3 solution has an important effect on the photoelectric response and photocatalytic properties of Ag-C-TiO₂ samples.In summary,the Ag-C-TiO₂ sample formed under the condition of 650 ? thermal oxidation temperature and 0.03 mol/L Ag NO3 solution concentration showed the best photoelectric response and photocatalytic properties.The transient photocurrent density of the samples under visible light and UV light are 460 uA/cm2 and 780 uA/cm2,respectively.After 4 hours photocatalyticdegradation rate of Rh B was 91% under visible light,and after 2 hours the rate was 92 % under UV light.