硫掺杂纳米TiO_2可见光催化剂的制备及光催化活性

用钛酸丙酯和硫脲为原料在煅烧条件下制备了硫掺杂纳米TiO2光催化剂,用XRD、XPS、TEM和UV-vis吸收光谱对催化剂进行了表征;分别以紫外光与太阳光为光源,甲基橙为目标降解物,评价了催化剂的光催化活性。结果表明,500℃煅烧的硫掺杂TiO2在紫外光区和可见光区的吸光度比纯TiO2提高了约0.23~0.46;经40~50 min降解,其在紫外光和太阳光下对甲基橙的降解率比纯TiO2分别提高了32%和69%。TEM结果表明,500℃煅烧的硫掺杂TiO2的粒径约为15~16 nm;XRD分析结果表明,硫掺杂能够促进TiO2从锐钛矿相向金红石相的转变,减小催化剂的晶粒粒径;XPS分析结果指出,硫原子的氧化态为+6,S6+部分取代了TiO2晶格中的Ti4+,形成了硫掺杂的TiO2光催化剂。

Preparation and Visible-light-activity of Sulfur-doped TiO2 Nanophotocatalysts

S-doped TiO2 visible-light activated photocatalysts were prepared under calcining conditions,using titanium isopropoxide and thiourea as starting materials.UV light and sunlight were used as light source to investigate the photocatalytic activity of the catalyst for the degradation of methyl orange.Compared with pure TiO2,the absorbance of S-doped TiO2 calcined at 500 ℃ is increased about 0.23～0.46 under visible and ultraviolet light,and the photocatalytic degradution rate of methyl orange with S-doped TiO2 calcined at 500 ℃ is enhanced about 32% and 69% respectively under ultraviolet light and solar light after 40～50 min.TEM results confirm that the average diameter of S-doped photocatalysts calcined at 500 ℃ is about 15～16 nm.XRD results show that S-doping can promote the phase transformation of TiO2 from anatase to rutile,and reduce the crystallite size of photocatyalysts.XPS results indicate that the oxidation state of the S atom substituted for some of the lattice titanium atoms in S-doped TiO2 is mainly S6+.