(湖南理工學院 化學化工學院，岳陽 414006)
摘 要: 采用一步水熱法制備ZnO/ZnAl2O4復合光催化劑前驅(qū)體。用不同量的磷酸溶液通過浸漬蒸干法對樣品進行修飾，并于不同溫度下焙燒獲得高活性ZnO/ZnAl2O4納米復合光催化劑。采用XRD、SEM、TEM、BET和TG-DTA 等技術(shù)對所得樣品進行表征。在模擬太陽光下，以光催化降解甲基橙和還原CO2評價樣品的光催化活性，并考察磷酸修飾量、樣品焙燒溫度對光催化活性的影響。結(jié)果表明：磷酸修飾可提高樣品的高溫穩(wěn)定性、晶化程度及比表面積。當磷酸修飾量為n(Zn):n(P)為100:2.0時，經(jīng)500 ℃焙燒后所得樣品的光催化活性最佳。當光催化劑用量為0.5 g/L時，在60 min內(nèi)對25 mg/L甲基橙溶液的脫色率達到98%，較未修飾樣品的提高15.3%。對最佳條件下所得樣品進行CO2光催化還原，當催化劑用量為1.0 g/L、反應(yīng)6 h后，所得還原產(chǎn)物中甲醇的生成量為1.60 mmol/g。
關(guān)鍵字: ZnO/ZnAl2O4；磷酸修飾；光催化活性；催化劑
（School of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006, China）
Abstract:ZnO/ZnAl2O4 precursor was synthesized by one-pot hydrothermal method. Phosphoric acid (H3PO4) was loaded on the precursor by an impregnation and steam seasoning process to obtain ZnO/ZnAl2O4 composite photocatalyst with high photocatalytic activity after calcination. The as-prepared samples were characterized by XRD, SEM, TEM, BET and TG-DTA techniques. The photocatalytic activities of the samples were evaluated by degradation of methyl orange (MO) and reduction of CO2 under the simulated sunlight irradiation. The effects of the amount of H3PO4 modification and calcinations temperature on the photocatalytic activities of the samples were investigated. The results indicate that H3PO4 modification improves the high temperature stability, degree of crystallization and specific surface area of the samples. The maximum of 98% photocatalytic decoloration rate of MO is achieved within 60 min at 0.5 g/L concentration of sample obtained at the mole ratio of Zn to P 100:2 and the calcination temperature of 500 ℃, which increases by 15.3% compared to that of bare ZnO/ZnAl2O4. Meanwhile, the main reduction products, methanol, the maximum yield of 1.60 mmol/g within 6 h is obtained at 1.0 g/L concentration of the same sample.
Key words: ZnO/ZnAl2O4; H3PO4 modification; photocatalytic activity; catalyst
