| The solar energy conversion and environmental purification are important problems which should be resolved right now. There are many methods for disposing contaminations, among which the multiphase photocatalysis for the degradation of contaminations of photocatalytic technology. The research and development began with pohotoelectrochemical solar conversion and then shifted into the area of environment photocatalysis, including self-cleaning surfaces and the area of photoinduced hydrophilicity, have enormous social and economic benefit. Titanium dioxide (TiO2) is a well-known photocatalyst in the depuration of air and water. However, it is activated only under UV light irradiation (only3%of solar spectrum) because its large band gap. So it is urgent need to develop efficient visible-light-driven photocatalysts by modification of TiO2which allow the main part of the solar spectrum (45%or so) to be used.After experimental discovery of graphene in2004, as a one-atom-thick sheet of sp--bonded carbon atoms in a hexagonal two-dimensional lattice, Concerning the unique properties of graphene, it has been predicted that the electron transfer rate and mechanical stiffness of graphene sheets may remarkably～15000cm2V-1s-1and1Tpa respectively. Hence, graphene with well-separated two-dimensional aromatic sheets may be applied as an excellent sensitizer of semiconductor photocatalyst such as TiO2Two dimensional sheets can serve as a support material with which to anchor semiconductor particles and improve the performance of the photocatalysts.Sulfur (S), nitrogen (N)-doped TiO2-GO composites were environmentally synthesized using thiourea (CS(NH2h) as a binary-element doping reagent by a simple colloidal blending method. The properties of composites had been characterized by means of TEM, AFM. EDX, XRD, BET, UV-vis DRS, EIS.The XRD results shows that in the N,S-doped TiO2-GO, the anatase phase TiO2could be obtained at a high calcination temperature, indicating that the S, N-doped TiO2samples exhibit considerably high thermal stability and highly resistant to the rutile phase transformation.From TEM and AFM image, the morphologies and structures can be seen that TiO2 nanoparticles with a diameter of about15nm are absorbed onto the surface of GO sheets and the TiO2nanoparticles were eager to accumulate and disperse along the edges of the wrinkled GO sheets.From the BET results, The TiO2/GO showed a specific surface area of150m2/g, which is three times larger than TiO2obtained by a conventional method.From UV-vis DRS results. Compared with TiO2. the absorption edges of the TiO2-GO, and S,N-doped TiO2-GO are found to shift to the lower-energy region.From the EIS results, It is observed that with the introduction of GO and element S, N, the semicircle in the plot became shorter, which indicated a decrease in the solid state interface layer resistance and the charge transfer resistance on the surface. From the transient current results, The photocurrents of the TiO2, TiO2-GO and S,N-doped TiO2-GO composites are0.6μA,2.0μA and2.5μA, respectively.The S, N-doped TiO2-GO composites show higher photocatalytic degradation rates on methyl orange (MO) compared to TiO2. The average value of k (the apparent rate constant) for the S. N-doped TiO2-GO (k=0.035min-1) was found to be nine times that of TiO2grown solution (k=0.0038min-1) and four times that of P25(k=0.008min-1).2. Rutile TiO2nanoparticles were prepared by solvent-thermal method in the presence of acid. The influences of acid concentration, the different solvent on the size and morphology of rutile TiO2crystalline were investigated. |
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