氧化石墨烯可见光催化能力的影响因素

为了验证氧化石墨烯的光催化能力,研究能增强其光催化效果的最佳条件,用改进的Hummer法制备了氧化石墨烯及分散液,通过扫描电镜、透射电镜、红外图谱、拉曼光谱以及荧光共聚焦光谱,对氧化石墨烯的微观形貌、成分、结构进行表征研究;在光照条件下降解亚甲基蓝验证其光催化能力,通过改变催化剂浓度、搅拌条件、曝气氧气浓度和外加电流,研究了四种条件对光催化能力的影响.在亚甲基蓝浓度为40 mg/L,氧化石墨烯浓度为20 mg/L,曝气量为2 L/min,氧气浓度为50%时,2 h可见光照射后亚甲基蓝降解率为62.9%,总去除率为89.9%;当不进行曝气处理,外加电流密度为1 m A/cm~2时,2 h可见光照射后亚甲基蓝降解率为53%,总去除率为87.9%.氧化石墨烯可以通过光催化产生羟基自由基降解污染物,通过改变条件来增加自由基含量可以提升催化效果.

Influencing factors of visible light photocatalytic capacity of graphene oxide

In order to verify the photocatalytic ability of graphene oxide and the best conditions to enhance its photocatalytic effect, graphene oxide was prepared by modified Hummer method. Its microstructure, composition and structure were characterized by using SEM, TEM, Raman and Fluorescence confocal spectroscopy. Its photocatalysis efficiency was evaluated using methylene blue solution. The effects of graphene oxide content, stir, aeration oxygen concentration and impressed current on the catalytic performance were investigated. When the concentration of methylene blue was 40 mg/L, the concentration of graphene oxide was 20 mg/L, the aeration rate was 2 L/min, the oxygen concentration was 50%, the degradation rate of methylene blue was 62.9% after 2 h irradiation, and the total removal rate was 89.9%; when the aeration treatment was not carried out and the external current density was 1 mA/cm², the degradation rate of methylene blue was 53% after 2 h irradiation, and the total removal rate was 87.9%. Hydroxyl radicals are produced by graphene oxide photocatalysis, and catalytic effects can be improved by increasing hydroxyl radicals content.