C_3N_4-ZnO复合光催化剂的制备及光催化性能研究

Preparation and Photocatalytic Properties of C_3N_4-ZnO Composite photocatalysts

以三聚氰胺为原料,通过高温热解法制备C_3N_4;以硝酸锌、氢氧化钠为原料,通过水热法制备ZnO。将不同配比的C_3N_4和ZnO在乙醇中超声搅拌,制备得到C_3N_4-ZnO复合催化剂。研究结果发现复合催化剂(0.8C_3N_4-0.2ZnO)显示了良好光催化活性,在光照时间为15 min时,亚甲基蓝的降解率为86.4%,在光照30 min达到97%的降解率。对该光催化剂进行了动力学研究,发现0.8C_3N_4-0.2ZnO的降解速率常数为纯ZnO的3.11倍,是纯C_3N_4的1.83倍。利用傅里叶红外光谱(FTIR),扫描电子显微镜(SEM)等对所合成样品的进行了表征。

The C3N4 was synthesized by directly heating melamine and ZnO was prepared from zinc nitrate and sodium hydroxide by hydrothermal method. C3N4-ZnO composite photocatalysts were prepared by ultrasonic mixing of C3N4 and ZnO with different ratios in ethanol. The composition and morphology of photocatalysts were investigated by Fourier transform infrared spectroscopy(FTIR), scanning electron microscopy(SEM) techniques. The photocatalytic activity of the samples was evaluated with methylene blue as the simulated pollutant under xenon lamp.The results showed that the photocatalytic activity of C3N4-ZnO for photodegradation of MB was higher than that of pure C3N4 and ZnO, the degradation rate of methylene blue reached 86.4% in 15 min, and 97% in 30 min with C3N4 content of 80%(wt). The kinetic study showed that the degradation rate constant of 0.8 C3N4-0.2 ZnO was 3.11 times that of ZnO and 1.83 times that of pure C3N4.