直接Z-型立方/六方ZnIn2S4复合光催化剂的制备及其光催化性能

通过水热反应方法制备出立方相ZnIn₂S₄和六方相ZnIn₂S₄和系列不同摩尔比的复合相ZnIn₂S₄光催化剂，使用X射线衍射、扫描电子显微镜、电子能谱、透射电子显微镜、光致发光光谱、N₂吸附-脱附法及紫外-可见光漫反射等手段表征了样品的晶体结构、显微结构及吸光特性并在可见光照射下进行了甲基橙降解实验。结果表明，复合相ZnIn₂S₄样品都具有比立方相、六方相和机械混合的ZnIn₂S₄更好的可见光催化活性，当复合相ZnIn₂S₄样品中立方相与六方相摩尔比为3:7时体系的催化活性最高。这种样品被可见光照射30 min后，甲基橙的降解率达到95.2%。其降解机理与样品较大的比表面积以及样品中的立方相与六方相之间的密切接触而形成直接Z-型光催化过程有关。

Preparation and Photocatalytic Properties of Direct Z-Scheme Hexagonal/Cubic ZnIn2S4 Composite Catalysts

Photocatalysts of cubic ZnIn₂S₄ and hexagonal ZnIn₂S₄ as well as a series of Cubic ZnIn₂S₄/hexagonal ZnIn₂S₄ composite with different molar ratios were synthesized via hydrothermal method. The crystal structure, microstructure and optical absorption property of the as-synthesized photocatalysts were characterized by means of X-ray diffractometer, scanning electron microscopy, transmission electron microscopy, photoluminescence spectrometer, Brunauer-Emmett-TeIler analysis and UV-visible diffuse reflectance spectroscopy. The photocatalytic activities of the prepared photocatalysts were evaluated through photocatalytic degradation of methyl orange under visible-light irradiation. Results show that all the composite photocatalysts have much better photocatalytic activity than that of the catalysts of cubic ZnIn₂S₄ and hexagonal ZnIn₂S₄ as well as the mechanically mixed ZnIn₂S₄ of the above two pure catalysts; Among others, the composite with more ratio 3:7 for cubic ZnIn₂S₄ to hexagonal ZnIn₂S₄ presents the highest photocatalytic activity with degradation efficiency for methyl orange up to 95.2% under visible-light irradiation for 30 minutes. This property can be attributed to the much larger specific surface areas and a direct Z-scheme photocatalytic process due to the close contact of cubic ZnIn₂S₄ and hexagonal ZnIn₂S₄ produced by the hydrothermal synthesis process.