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- 2016
具有超快吸附能力的(C,N)-TiO2光催化材料
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Abstract:
采用“溶胶-凝胶与微波二步法”合成了碳、氮掺杂的锐钛矿(C,N)-TiO2光催化材料. 首先采用溶胶-凝胶方法制备了TiO2前驱物凝胶粉末，然后将其与盐酸胍混合微波制备(C,N)-TiO2纳米材料. 对该材料进行X射线衍射(XRD)、扫描电子显微镜(SEM)、紫外-可见漫反射光谱(UV-Vis DRS)等表征，并测试在甲基橙溶液（100 mg/L）中的黑暗吸附以及饱和黑暗吸附后的甲基橙光催化降解等性能. 结果表明，获得的材料为纯锐钛矿相的二氧化钛. 颗粒分散好，平均粒径约20 nm. 具有大的比表面积. 随着C、N含量的增加，可见光区域的吸收增加，而紫外光区域的吸收基本不随C、N的含量变化；所制备的(C,N)-TiO2对甲基橙溶液具有超快的黑暗吸附能力(〖WTBX〗t〖WTBZ〗<1 min)；在微波处理中，随着盐酸胍的添加量增加，光催化的量子效率先增加后减小. 最好的样品能在20 min内对甲基橙的降解效率达到93%. 在可见光区域的吸收与黑暗吸附2个因素中，黑暗吸附的作用更大. 文章认为微波处理光催化材料的方法简单、快速、节能,是提高光催化速率的有效途径，值得推广.
： A kind of nitrogen and carbon co-doped titanium dioxide ((N,C)-TiO2) was prepared by a simple, fast and energy-saving method, by which composite consisting of TiO2 precusor (fabricated by sol-gel method) and guanidine hydrochloride was irradiated by microwave. X-Ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible diffuse reflection spectra (UV-Vis DRS), dark adsorption of methylene orange and photo-catalysis were employed to characterize the prepared samples. It is shown that the prepared samples are pure anatase TiO2 with large specific area and good disperse, homogeneous nanosized particle size (20 nm). The Vis absorption of prepared powders increases with increased content of guanidine hydrochloride in above-said composite. In the meantime, a very fast and high dark adsorption is found in as-fabricated powders. The time when the dark adsorption reaches to saturation is less than 1 min. And the photocatalytic degradation firstly increases, then decreases with increased content of guanidine hydrochloride in above-said composite. The best saturated photocatalytic degradation is 93% within 20 min. It is also found that between the two factors -Vis absorption and dark adsorption, the dark adsorption plays more important role in photocatalytic activity. It can be concluded that the microwave-assisted method can introduce pores or lead to smaller particle size in as-prepared powdered photocatalysts
