Abstract Influence of nitrogen precursors urea, semicarbazide and N,N’-dimethyl urea on the photocatalytic activity of the N-doped TiO2 were studied by a simple decomposition method. The nano N-TiO2 catalysts were synthesized via two different modified approaches by calcination at 500 oC. The synthesized samples were characterized by IR, UV-DRS, Raman, TG-DTA, XRD, EDX, XPS, SEM, TEM and BET analysis. Of the synthesized six samples of N-TiO2 five samples showed better photocatalytic activity towards direct sunlight photo-degradation of methylene blue (MB) and rhodamine B (RhB) than Degussa P25. The catalysts obtained using semicarbazide samples F3 and F4 having large surface area of 76 and 85.8 m2/g displayed maximum photocatalytic activity. The sample F4 was 1.5 times more active than Degussa P25 for the decolourisation of MB and 1.9 times more active for the decolourisation of RhB. The presence of nitrogen, large surface area and coupling of rutile-anatase phases were found to be the main responsible factors for the enhanced photocatalytic activity. The exclusive formation of the anatase phase in the case of urea precursor is attributed to the slow evaporation of urea due to the formation of melamine derived products. The calcination temperature is the deciding factor responsible for the photocatalytic activity of the N-TiO2 samples prepared from precursors which can potentially form the melamine and its oligomerized products on the surface of TiO2.

中文翻译：

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N源对N掺杂TiO2光催化活性的影响

摘要 采用简单分解法研究了氮前驱体尿素、氨基脲和N,N'-二甲基尿素对N掺杂TiO2光催化活性的影响。通过在 500 oC 下煅烧，通过两种不同的改进方法合成了纳米 N-TiO2 催化剂。合成的样品通过 IR、UV-DRS、拉曼、TG-DTA、XRD、EDX、XPS、SEM、TEM 和 BET 分析表征。在合成的六个 N-TiO2 样品中，五个样品对亚甲蓝 (MB) 和罗丹明 B (RhB) 的阳光直射光降解表现出比 Degussa P25 更好的光催化活性。使用具有 76 和 85.8 m2/g 的大表面积的氨基脲样品 F3 和 F4 获得的催化剂显示出最大的光催化活性。对于 MB 和 1 的脱色，样品 F4 的活性是 Degussa P25 的 1.5 倍。对 RhB 脱色的活性提高 9 倍。发现氮的存在、大表面积和金红石-锐钛矿相的偶联是光催化活性增强的主要因素。在尿素前体的情况下，锐钛矿相的唯一形成归因于尿素由于三聚氰胺衍生产物的形成而缓慢蒸发。煅烧温度是决定由前体制备的 N-TiO2 样品光催化活性的决定因素，前体可能在 TiO2 表面形成三聚氰胺及其低聚产物。在尿素前体的情况下，锐钛矿相的唯一形成归因于尿素由于三聚氰胺衍生产物的形成而缓慢蒸发。煅烧温度是决定由前体制备的 N-TiO2 样品光催化活性的决定因素，前体可能在 TiO2 表面形成三聚氰胺及其低聚产物。在尿素前体的情况下，锐钛矿相的唯一形成归因于尿素由于三聚氰胺衍生产物的形成而缓慢蒸发。煅烧温度是决定由前体制备的 N-TiO2 样品光催化活性的决定因素，前体可能在 TiO2 表面形成三聚氰胺及其低聚产物。