Laboratory of Plant Nutrition and Ecological Environment Research, Centre for Microelement Research of Huazhong Agricultural University, Ministry of Agriculture, Wuhan 430070, People's Republic of China.
Nanotechnology. 2012 Jul 27;23(29):294003. doi: 10.1088/0957-4484/23/29/294003. Epub 2012 Jun 28.
We have demonstrated heterogeneous photocatalytic degradation of microcystin-LR (MC-LR) by visible light activated carbon doped TiO(2) (C-TiO(2)) nanoparticles, synthesized by a modified sol-gel route based on the self-assembly technique exploiting oleic acid as a pore directing agent and carbon source. The C-TiO(2) nanoparticles crystallize in anatase phase despite the low calcination temperature of 350 °C and exhibit a highly porous structure that can be optimized by tuning the concentration of the oleic acid surfactant. The carbon modified nanomaterials exhibited enhanced absorption in the broad visible light region together with an apparent red shift in the optical absorption edge by 0.5 eV (2.69 eV), compared to the 3.18 eV of reference anatase TiO(2). Carbon species were identified by x-ray photoelectron spectroscopy analysis through the formation of both Ti-C and C-O bonds, indicative of substitution of carbon for oxygen atoms and the formation of carbonates, respectively. Electron paramagnetic resonance spectroscopy revealed the formation of two carbon related paramagnetic centers in C-TiO(2), whose intensity was markedly enhanced under visible light illumination, pointing to the formation of localized states within the anatase band gap, following carbon doping. The photocatalytic activity of C-TiO(2) nanomaterials was evaluated for the degradation of MC-LR at pH 3.0 under visible light (λ > 420 nm) irradiation. The doped materials showed a higher MC-LR degradation rate than reference TiO(2), behavior that is attributed to the incorporation of carbon into the titania lattice.
我们通过可见光激活的掺碳 TiO2（C-TiO2）纳米粒子实现了微囊藻毒素-LR（MC-LR）的多相光催化降解，该纳米粒子通过改良的溶胶-凝胶路线合成，利用油酸作为孔导向剂和碳源，采用自组装技术。尽管煅烧温度低至 350°C，C-TiO2 纳米粒子仍结晶为锐钛矿相，并表现出高度多孔的结构，通过调节油酸表面活性剂的浓度可以优化这种结构。与参考锐钛矿 TiO2 的 3.18 eV 相比，改性纳米材料在宽可见光区域的吸收增强，并在光学吸收边缘出现明显的红移 0.5 eV（2.69 eV）。X 射线光电子能谱分析通过形成 Ti-C 和 C-O 键鉴定了碳物种，这表明碳分别替代了氧原子并形成了碳酸盐。电子顺磁共振光谱表明，在 C-TiO2 中形成了两个与碳有关的顺磁中心，在可见光照射下其强度明显增强，这表明在碳掺杂后，在锐钛矿带隙内形成了局部态。在 pH 3.0 下，在可见光（λ>420nm）照射下，评价了 C-TiO2 纳米材料对 MC-LR 的光催化降解活性。与参考 TiO2 相比，掺杂材料表现出更高的 MC-LR 降解速率，这归因于碳掺入到二氧化钛晶格中。
