Preparation Of One-dimensional SnO₂/TiO₂ Composite Film Electrodes And Their Photoelectrocatalytic Properties

In recent years, there has been increasing interest in the research of wide band gap semieonduetors due to the huge commereial desire for short-wavelength luminescent deviees. SnO2 is a typical semiconductor material of broadband gap n-type semiconductor materials (Eg=3.6eV, 300K). However, SnO2 band gap is wide while the conduction band is lower, it is difficult to stimulate the electron. So it is necessary to choose a kind of semiconductor that the band gap is relatively narrow while the conduction band is higher. There have been reports about the SnO2/TiO2 complex system, indicating that the accouplement between SnO2 and TiO2 resulting effective isolation of electron and electron hole, decrease the probability of composition, enhance the photoelectric properties of SnO2/TiO2 complex system. However, for the most part, researchers obtain the complex through sol-gel method or Gas phase precipitation, these methods are expensive, need rigorous condition and hard to use practically. To seek a more simple method, it has been reported that preparate SnO2/TiO2 complex system by electrostatic spinning,but most are according to use TiO2 as basement or spinning with mixing the precursor solution, using SnO2 nanometer preparated by electrostatic spinning as basement, adding TiO2 partical have not been reported.In this dissertation, sol-gel method was applied to prepare One-dimensional SnO2 nanowires. first, we prepared the precursor solution with a viscosity, and electrospinning technique was used to fabricate PVP/SnCl2·2H2O composite nanoribbons. The morphology of fibers were discussed by adjusting all the important parameters such as concentration of PVP, voltage, distance between tip and collector, the mass of metal salts added to the sol. Then,we can get One-dimensional SnO2 nanowires after calcination at 500℃for 5 hours, Tin dioxide (SnO2) nanowires with diameter of 90-180 nm were obtained via electrostatic spinning technique by controlling the concentration of SnCl2·2H2O in the precursor solution. SnO2/TiO2 composite film electrodes were prepared after hydrolization of TiCl4 solution.The prepared film electrodes were characterized by SEM and EDS, respectively. Photoelectrochemical properties of the SnO2/TiO2 composite film electrodes were studied using electrochemical techniques including linear sweep voltammetry and photoelectrocatalysis. Under optimal the precursor solution of 3%, the photoelectric properties of the SnO2/TiO2 composite film electrodes were the best. Compared to pure TiO2 or SnO2 film electrode, the photocurrent of the SnO2/TiO2 composite film electrode increased significantly. The photocatalytic degradation rate of rhodamine B (RhB) with composite film electrode was 95% after 90 min of radiation, compared to pure TiO2 56% and SnO2 58%.