二氧化钛/石墨烯光催化降解草酸的研究

Photocatalytic Degradation of Oxalic Acid by TiO_2/ Graphene Composite

以钛酸四丁酯和氧化石墨烯为原料,采用水热法制备了二氧化钛/石墨烯(Ti O2/RGO)复合光催化剂,用XRD、TEM、UV-Vis DRS对光催化剂进行了表征.研究了其在紫外光和模拟太阳光条件下对草酸的光催化降解性能,结果表明,与Ti O2相比,Ti O2/RGO在紫外光条件下,反应10 min后对草酸的光催化降解率增加了2.97%,这主要是因为石墨烯为Ti O2提供了电子转移场所,提高了电子-空穴的分离效率;而在模拟太阳光条件下,反应10 min后Ti O2/RGO对草酸的光催化降解率增加了9.05%,除了提高量子利用率外,石墨烯的加入使得Ti O2的吸收边带红移,增加了对可见光的吸收.同时发现p H主要是通过影响催化剂表面电荷、电势以及对目标物的吸附来影响Ti O2/RGO光催化活性.添加叔丁醇(TBA)的光催化实验结果表明:·OH是Ti O2/RGO光催化体系中的主要活性物质之一.

A TiO2/Graphene （TiO2/RGO） composite was synthesized by a hydrothermal method using graphite oxide and tetrabutyl. The crystal phase and morphology were characterized by X-ray diffraction, transmission electron microscope, and UV-Vis diffuse reflectance spectroscopy. The photocatalytic activity of TiO2/RGO was evaluated by the degradation of oxalic acid aqueous under UV light and simulated solar light irradiation. The results show that the TiO2/RGO photcatalytic degradation ratio of oxalic acid aqueous have increased 2.97% under UV light irradiation compared with TiO2 after 10 min reaction. The enhancement was attributed to the high electric charge carrier mobility of RGO, so the electrons can be transmitted to the surface of RGO from TiO2, which hindered the recombination of photogenerated electrons and holes. Under the simulated solar light irradiarion, H2C2O4 removal rate with TiO2/RGO photocatalytic was increased 9.05% compared with TiO2 photocatalytic. With the introduction of graphene, the absorption of TiO2 sideband was redshift, which increased the absorption of visible light. The effects of pH and the free radical scavenger （ Tert-Butyl alcohol） were analyzed. The results show that the effect of pH on the photocatalytic activity of TiO2/RGO is mainly influenced by surface charge of TiO2/RGO, as well as the adsorption of H2C204 by TiO2/RGO. The result of the effect of tert-butyl alcohol experiment shows that the . OH is one of the main active substances in the TiO2/RGO photocatalytic system.