School of Mechanical and Power Engineering, Shanghai Jiaotong University, Shanghai, China.
J Hazard Mater. 2011 Dec 30;198:78-86. doi: 10.1016/j.jhazmat.2011.10.012. Epub 2011 Oct 6.
A series of graphene/titanate nanotubes (TNTs) photocatalysts using graphene and nanoscale TiO(2) or P25 as original materials were fabricated by hydrothermal method. Both low hydrothermal temperature and proper amount of graphene are propitious to better photoactivity. The photocatalytic activities of these nanocomposites far exceed that of P25, pure TNTs and reported TiO(2)-based nanocomposites for the degradation of Rhodamine-B under visible-light irradiation. These prepared photocatalysts were characterized by TEM, XRD, XPS, BET, FTIR and UV-vis diffuse reflection spectra, and the results indicate that the outstanding photoactivities in visible-light region result from sensitization effect of graphene rather than impurity level in the band gap of TNTs. Furthermore, large BET surface areas of these photocatalysts (almost 10 times larger than that of previously reported graphene/TiO(2) nanoparticles) evidently enhance their absorption abilities and photocatalytic performances (the rate constants of degrading Rhodamine-B are at least 5 times higher than that of previously reported photocatalysts). These photocatalysts show good stability, and their photoactivities do not obviously decrease after four times of repeated uses. A detailed photocatalytic mechanism is suggested, as well.
采用水热法制备了一系列以石墨烯和纳米 TiO2 或 P25 为原料的石墨烯/钛酸盐纳米管（TNTs）光催化剂。较低的水热温度和适量的石墨烯有利于获得更好的光活性。在可见光照射下，这些纳米复合材料对 Rhodamine-B 的降解光催化活性远远超过 P25、纯 TNTs 和已报道的基于 TiO2 的纳米复合材料。通过 TEM、XRD、XPS、BET、FTIR 和 UV-vis 漫反射光谱对这些光催化剂进行了表征，结果表明，在可见光区的优异光活性源于石墨烯的敏化效应，而不是 TNTs 带隙中的杂质能级。此外，这些光催化剂具有较大的 BET 比表面积（比以前报道的石墨烯/TiO2 纳米颗粒大近 10 倍），明显增强了它们的吸收能力和光催化性能（降解 Rhodamine-B 的速率常数至少比以前报道的光催化剂高 5 倍）。这些光催化剂表现出良好的稳定性，经过四次重复使用后，其光活性没有明显下降。还提出了详细的光催化机理。
