ZnO/Bi_2WO_6异质结的制备及光催化制氢研究

Synthesis of ZnO/Bi_2WO_6 Heterojunction and Research of Photocatalytic Hydrogen Evolution

试验采用水热法制备出薄片状Bi_2WO_6,并通过异质外延生长法在Bi_2WO_6薄片上生长ZnO纳米线微米盘,得到ZnO/Bi_2WO_6异质结。对样品进行的主要表征有扫描电子显微镜形貌观察、X射线粉末衍射、能谱分析、电化学阻抗谱等。结果表明,ZnO/Bi_2WO_6异质结由直径约1μm、厚度为40~60 nm的Bi_2WO_6微米盘负载ZnO纳米线构成。在可见光下,ZnO/Bi_2WO_6异质结的光催化制氢性能明显优于纯ZnO及纯Bi_2WO_6,ZnO/Bi_2WO_6异质结的稳定性也较高。试验对比了纯Bi_2WO_6与ZnO/Bi_2WO_6异质结在可见光下催化制氢的速率,发现ZnO/Bi_2WO_6异质结的光催化效果明显高于纯Bi_2WO_6,且当生长母液浓度为8 mM(mmol/L)时,制氢速率最大为12 290.2μm·mol·h^(-1)·g^(-1),比纯Bi_2WO_6提高了2.2倍,在其循环试验18 h后,ZnO/Bi_2WO_6异质结仍能保持较稳定的制氢速率,保持率达到90%。

Hydrothermal method was used to synthesize Bi2WO6 sheets,and ZnO/Bi2WO6 heterojunction material was prepared by heteripitaxial growth of ZnO nanorod microdisk on Bi2WO6 sheets.The prepared catalysts were characterized by X-ray powder diffraction,scanning electron microscopy,energy dispersive spectroscopy,electrochemical impedance spectroscopy and UV-visible diffuse reflectance spectroscopy.The results show that ZnO/Bi2WO6 heterojunctions are composed of ZnO nanowire arrays with different sizes and circular Bi2WO6 with diameter of about 1μm and thickness of 40-60 nm.The photocatalytic activity of ZnO/Bi2WO6 heterogeneous composite photocatalyst is better than that of pure ZnO and pure Bi2WO6.The photocatalytic activity of ZnO/Bi2WO6 heterojunction photocatalyst was significantly higher than that of pure Bi2WO6.When the concentration of the growth solution was 8 mM(mmol/L),the maximum rate of hydrogen production is 12 290.2μm·mol·h-1·g-1,which is 2.2 times higher than that of pure Bi2WO6,the ZnO/Bi2WO6 heterojunction could maintain certain stability of hydrogen production rate after 18 h,and the retention rate had reached 90%.