Fabrication And Photoelectrocatalytic Properties Of Sulfur And Cerium Co-doped TiO₂Nanotube Arrays

The present work aimed to fabricate S-Ce co-doped TiO₂nanotube arrays by anodic oxidationand electrodeposition process to solve problems of low quantum yield and low efficiency to solar ofTiO₂photocatalyst.The S-doped TiO₂nanotube arrays were prepared by a one-step electrochemical anodizationprocess, and the possible mechanism of visible photoelectrocatalytic （PEC） activity was discussed.The result indicated that the introduced sulfur was probably incorporated into TiO₂and that thechemical states was S6+substituted for Ti4+cation, the chemical environmental surrounding sulfur wasS-O-Ti. The absorption intensity of modified TiO₂nanotube arrays to visible light was wider than thatof unmodified TiO₂nanotube arrays. The PEC activity of the S-doped TiO₂nanotube arrays wasstrongly dependent on the doping content, and the0.39at.%S-doped TiO₂nanotube arrays displayedthe strongest absorption intensity and highest level of PEC activity. The absorption edge shifted45nm to lower energy. PEC activity for oxidation of methyl orange was remarkably improved; thedegradation rate was increased by11.5%than that of TiO₂nanotube arrays under visible lightirradiation, and38.2%under ultraviolet （UV） light irradiation.S-Ce co-doped TiO₂nanotube arrays were prepared by electrodeposition at a constant currentbasing on the0.39at.%S-doped TiO₂nanotube arrays. The result showed that the S-Ce co-dopedTiO₂nanotube arrays which were fabricated with the current density of1mA/cm2last for4mindisplayed the strongest absorption intensity and highest level of PEC activity. The absorption edgeshifted63nm to lower energy. After40minutes, removed azo approximately1.13times faster thanthat of S-doped TiO₂nanotube arrays under visible light irradiation, and1.14times under UV lightirradiation, meanwhile, compared with that of TiO₂nanotube arrays,1.24times under visible lightlight irradiation, and1.52times under UV light irradiation.Irradiation oxidation technique is an efficient method of degradation for organics. However, highdosage will be devoted to irradiation treatment for wastewater, which needs a high operation cost. Inthis paper, TiO₂nanotube arrays and irradiation oxidation technique were combined to improve thedegradation of organics, and the feasibility of this system was invested. It showed that the presence ofTiO₂nanotube arrays evidently enhanced the degradation of methyl orange. There was a highest effectin the combination system, the degradation was5.7%higher compared with that of signal γ-rayirradiation, when the irradiation dosage was3KGy, Na₂SO₄concentration was0.4mol/L, and the pH value was3.