Study On Doping And Modification Of Titanium Dioxide Nanotubes And Their Photoelectric Performance

With unique combination of easy processing,low manufacturing cost,and high power conversion efficiency,the dye-sensitized solar cells（DSSC）have attracted intensive scientific interests in recent years.Titanium dioxides may work as the optical anode materials for the DSSC,but their band gaps are too wide to effectively absorb the most part of sunlight which limits the development of this technology.Therefore,the doping and modification of TiO₂,to broaden its absorption range,improve its utilization efficiency of sunlight is very important.In this paper,TiO₂ nanotubes and copper doped TiO₂ nanotubes were prepared by anodic oxidation using 4N grade titanium and copper-titanium alloy.The wettability was improved by DC magnetron sputtering of Ti or Cu₂O.In this work,methyl orange solution was used to carry out the photocatalytic experiment of titania nanotubes,and the photocatalytic efficiency was tested.The photocurrent response of nanotubes was tested by photocurrent experiments.The effects of different annealing conditions on the preparation of nanotubes were investigated,such as annealing time,annealing temperature and annealing atmosphere.And the photocatalytic efficiency and magnitude of photocurrent of the nanotubes prepared under different annealing conditions were tested.The prepared nanotubes were characterized by scanning electron microscopy（SEM）,X-ray diffraction（XRD）,X-ray photoelectron spectroscopy（XPS）,UV-Vis spectrophotometer and contact angle test.From the experiment we can know that the optimum annealing time was 2 h,the optimum annealing temperature was 500℃,the optimum annealing atmosphere was argon,annealing in ammonia and nitrogen,which greatly reduced the photocatalytic efficiency and magnitude of photocurrent of pure titanium.Because of the poor wettability of copper doped TiO₂ nanotubes,the photocatalytic efficiency and photocurrent efficiency of the prepared nanotubes were very bad.The wettability of the prepared nanotubes was greatly improved by magnetron sputtering,which could greatly improve the photocatalytic activity efficiency,in the light after 30 min,the degradation rate reached 60.10%,while the pure titanium was only 4.14%,the photocurrent also increased,but was not obvious.The results showed that pure Cu₂O could be prepared by DC reactive magnetron sputter with sputtering power being 76 W,sputtering pressure being 1.3 Pa and sputtering gas ratio of Ar to O₂ being 22:1.While the copper doped TiO₂ nanotubes sputtered by Cu₂O,the wettability could be improved and meanwhile broadened the light absorption range.After the experiment of photocatalytic degraded methyl orange,it was found that the degradation rate was 44.13%,compared with the degradation rate of untreated copper doped TiO₂ nanotubes which was 13.87%after 30 min illumination was greatly improved.