To enhance the photoactivity of TiO2 under visible light, doping TiO2 by sulfur atoms from sulfuric acid has been conducted by hydrothermal method, where the concentration of the acid is varied (25, 50, and 100 mmol/L) to obtain the doped TiO2-S with various S content. The doped photocatalysts obtained are characterized by using X-ray diffraction, ultraviolet specular reflectance spectrophotometer, Fourier transform infrared, and transmission electron microscope machines. The activity of the doped photocatalyst has been examined for Congo-red photo-decolorization under visible light, via batch experiment. The research results assigned that the doping sulfur into TiO2 has successfully narrowed the gap that resulted in the remarkable enhancement of the activity under visible light in the Congo red decolorization. The enhancement is influenced by S content in the photocatalyst and the highest activity is shown by TiO2-S prepared from 50 mmol/L sulfuric acids. The efficiency of the Congo-red photo-decolorization catalyzed by TiO2-S (50) is found to be controlled by reaction time, photocatalyst weight, and solution pH. By applying 50 mg of the photocatalyst weight in 50 mL of the dye solution with pH 7, within 60 min, the highest photo-decolorization of 10 mg/L Congo-red, that is 87% could be reached.

中文翻译：

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通过掺杂硫进行染料光脱色显着提高 TiO2 光催化剂在可见光下的活性

为了提高 TiO2 在可见光下的光活性，通过水热法将硫酸中的硫原子掺杂 TiO2，酸的浓度变化（25、50 和 100 mmol/L）以获得掺杂的 TiO2- S 具有各种 S 内容。使用X射线衍射、紫外镜面反射分光光度计、傅里叶变换红外和透射电子显微镜对得到的掺杂光催化剂进行表征。已通过批量实验检测了掺杂光催化剂在可见光下的刚果红光脱色活性。研究结果表明，在二氧化钛中掺杂硫成功地缩小了差距，导致刚果红脱色在可见光下的活性显着增强。这种增强受光催化剂中 S 含量的影响，由 50 mmol/L 硫酸制备的 TiO2-S 显示出最高的活性。发现由 TiO2-S (50) 催化的刚果红光脱色的效率受反应时间、光催化剂重量和溶液 pH 值的控制。在 50 mL 的 pH 值为 7 的染料溶液中加入 50 mg 的光催化剂重量，在 60 min 内，可达到 10 mg/L 刚果红的最高光脱色率，即 87%。