Ma Juanjuan, Zhou Chaocun, Long Jinlin, Ding Zhengxin, Yuan Rusheng, Xu Chao
State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University Fuzhou 350002 P. R. China
RSC Adv. 2018 Apr 16;8(25):14056-14063. doi: 10.1039/c8ra02268b. eCollection 2018 Apr 11.
Graphene-based cocatalysts can improve the photocatalytic properties of semiconductors, but sometimes, they also function as barrier-like materials, influencing the photoactivity of composites. However, in a multi-cocatalyst system, less attention is paid to these negative effects of graphene on the performance of other cocatalysts. In this study, by adjusting the loading sequence of graphene and Ag cocatalyst on the surface of TiO spheres, the barrier effect of graphene sheets on Ag nanoparticles could be controlled effectively. As a result, these ternary composites with almost no Ag nanoparticles wrapped by graphene possessed improved properties for the photocatalytic reduction of nitro-aromatics as compared to those with some Ag nanoparticles covered by graphene. Furthermore, this phenomenon of barrier effect caused by graphene could be found in the control reaction with metal silver as the main catalyst; this indicated that by avoiding the possible negative influence of graphene on other cocatalysts, the properties of composites with graphene-containing multi cocatalysts could be further improved.
基于石墨烯的助催化剂可以改善半导体的光催化性能，但有时它们也会起到类似屏障的材料的作用，影响复合材料的光活性。然而，在多助催化剂体系中，石墨烯对其他助催化剂性能的这些负面影响较少受到关注。在本研究中，可以通过调整石墨烯和银助催化剂在TiO球表面的负载顺序，有效控制石墨烯片对银纳米颗粒的屏障效应。结果，与一些被石墨烯覆盖的银纳米颗粒的复合材料相比，这些几乎没有被石墨烯包裹的银纳米颗粒的三元复合材料在光催化还原硝基芳烃方面具有更好的性能。此外，在以金属银为主要催化剂的对照反应中也发现了由石墨烯引起的这种屏障效应现象；这表明通过避免石墨烯对其他助催化剂可能产生的负面影响，可以进一步改善含石墨烯的多助催化剂复合材料的性能。
