School of Civil & Environmental Engineering, Nanyang Technological University (Singapore), 50 Nanyang Avenue, 639798 (Singapore), Fax: (+65) 67900676.
Chem Asian J. 2013 Nov;8(11):2779-86. doi: 10.1002/asia.201300565. Epub 2013 Aug 1.
Hierarchical graphene oxide (GO)-TiO2 composite microspheres with different GO/TiO2 mass ratios were successfully prepared by mixing GO and TiO2 microspheres under ultrasonic conditions. Ultrasonication helped the GO and TiO2 microsphere to uniformly mix on the microscale. The results showed that the GO-TiO2 composites that were prepared by ultrasonic mixing exhibited significantly higher hydrogen-evolution rates than those that were synthesized by simple mechanical grinding, owing to synergetic effects, including enhanced light absorption and scattering, as well as improved interfacial charge transfer because of the excellent contact between the GO sheets and TiO2 microspheres. In addition, GO-TiO2-3 (3 wt.% GO) showed the highest hydrogen-generation rate (305.6 μmol h(-)), which was about 13 and 3.3-times higher than those of TiO2 microsphere and GO-P25 (with 3 wt.% GO), respectively. Finally, a tentative mechanism for hydrogen production is proposed and supported by photoluminescence and transient photocurrent measurements. This work highlights the potential applications of GO-TiO2 composite microspheres in the field of clean-energy production.
具有不同 GO/TiO2 质量比的分层氧化石墨烯（GO）-TiO2 复合微球通过在超声条件下混合 GO 和 TiO2 微球成功制备。超声有助于在微尺度上均匀混合 GO 和 TiO2 微球。结果表明，通过超声混合制备的 GO-TiO2 复合材料由于协同效应，表现出比简单机械研磨合成的复合材料更高的析氢速率，协同效应包括增强的光吸收和散射，以及由于 GO 片和 TiO2 微球之间的优异接触而改善的界面电荷转移。此外，GO-TiO2-3（3wt.%GO）表现出最高的制氢速率（305.6μmol h-1），分别是 TiO2 微球和 GO-P25（含 3wt.%GO）的 13 倍和 3.3 倍。最后，通过光致发光和瞬态光电流测量提出了一个产氢的推测机制，并得到了支持。这项工作突出了 GO-TiO2 复合微球在清洁能源生产领域的潜在应用。
