匀胶法制备改性石墨烯光催化薄膜的工艺及光催化性能

Spin coating process and photocatalytic activities of modified graphene thin film

采用改进的Hummers法制备改性石墨烯分散液,然后用匀胶法在玻璃基底上制备改性石墨烯薄膜,研究低速(600~800 r/min)、中速(1 000~2 000 r/min)、高速(3 000~5 000 r/min)、滴胶时间(10~30 s)、加速度(100~700r/(min·s))和pH值(4~11)等匀胶工艺参数对改性石墨烯薄膜附着力的影响,优化匀胶工艺参数。通过扫描电镜(SEM)、透射电镜(TEM)、能谱仪、拉曼光谱以及激光共聚焦光谱,对最佳工艺下制备的改性石墨烯及其薄膜进行表征,重点研究可见光下改性石墨烯薄膜对亚甲基蓝的光催化降解性能,分析其可见光光催化原理。结果表明:在低速800 r/min旋转60 s,然后中速1 500 r/min旋转30 s,高转速4 000 r/min下旋转60 s,滴胶时间为20 s,加速度为100 r/(min·s),分散液pH=7条件下制备的改性石墨烯薄膜附着力最好。薄膜在可见光波段波长为421 nm处有最大吸收峰,对亚甲基蓝溶液进行光催化降解,4 h时降解率达到34.4%。其催化原理为改性石墨烯薄膜在可见光的作用下,产生强氧化剂·OH,把亚甲基蓝等污染物逐步氧化成二氧化碳和水,达到降解的目的。

Modified graphene dispersion was prepared by the modified Hummer method, and the modified graphene film was prepared on the glass substrate by spin coating method. The effects of low speed （600？800 r/min）, medium speed （1 000？2 000 r/min）, high speed （3 000？5 000 r/min）, dropping time （10？30 s）, acceleration （100？700 r/（min·s）） and pH value （4？11） on the adhesion of the thin graphene film were studied, and the optimized spin coating process parameterts were obtained. The modified graphene and its film were characterized by scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, energy dispersive spectroscopy, Raman spectroscopy and laser confocal spectroscopy. The effect of the modified graphene film on the degradation of methylene blue in visible light was emphasically studied, and the photocatalytic principle of visible light was preliminarily revealed. The results show that the modified graphene film with the optimum adhesion can be obtained by rotating the modified graphene dispersion whose pH value is 7 and the dripping time is 20 s at the low speed of 800 r/min for 60 s at first, the medium speed of 1500 r/min for 30 s, and the high speed 4000 r/min for 60 s at last, with an acceleration rate of 100 r/（min·s）. The modified graphene film exists the maximum absorption peak at 421 nm in the visible wavelength band. The visible photo degradation rate of methylene blue by the modified graphene film is 34.4% for 4 h. Its catalytic principle is that the graphene film generats a strong oxidant ？ OH in the visible light, which can gradually degrade methylene blue and other pollutants into carbon dioxide and water, then the purpose of degradation is ultimately achieved.