表面改性ZnIn_(2)S_(4)纳米片及助催化剂MoS_(2)修饰提高其光催化性能

Surface-modified ZnIn_(2)S_(4)Nanosheets and Co-catalyst MoS_(2)Modification to Improve Its Photocatalytic Activity

我们设计了一种具有丰富活性位点和高效电荷分离的MoS_(2)/ZnIn_(2)S_(4)光催化剂体系。首先采用低温回流法通过添加少量的柠檬酸钠对ZnIn_(2)S_(4)纳米片的尺寸进行调控从而制备了具有丰富活性位点ZnIn_(2)S_(4)纳米片。进一步通过简单的光辅助沉积法将不同质量MoS_(2)负载在ZnIn_(2)S_(4)纳米片表面合成MoS_(2)/ZnIn_(2)S_(4)复合材料。通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)、X射线能谱仪(EDS),紫外-可见漫反射(UV-vis DSR)和电化学性能测试等表征手段对材料的形貌、结构和性能进行分析。经研究发现,ZnIn_(2)S_(4)纳米片较块状ZnIn_(2)S_(4)具有丰富的活性位点,MoS_(2)/ZnIn_(2)S_(4)复合光催化剂较纯ZnIn_(2)S_(4)纳米片光催化剂而言,具备以下优异性能:光的吸收率和光电流强度明显提升,阻抗显著降低,光生载流子分离效率得到显著性增强。当MoS_(2)的质量比为3%时,在光源为AM1.5的300 W氙灯照射下,MoS_(2)/ZnIn_(2)S_(4)光催化剂的光解水平均产氢率达到最佳为17.346 mmol·g^(-1)·h^(-1),是纯ZnIn_(2)S_(4)纳米片析氢速率的3.35倍,是块状ZnIn_(2)S_(4)的13.55倍。在三次循环后,其性能保持在90%,具有良好的稳定性,因此构建MoS_(2)/ZnIn_(2)S_(4)光催化体系可有效提高单组分光催化剂ZnIn_(2)S_(4)光催化性能。

In this study,we designed a MoS_(2)/ZnIn_(2)S_(4)photocatalyst system with abundant active sites and efficient charge separation.ZnIn_(2)S_(4)nanosheets with abundant active sites were prepared by modulating the size of the nanosheets with a small amount of sodium citrate by low-temperature refluxing method,and further MoS_(2)/ZnIn_(2)S_(4)composite photocatalyst was synthesized by loading different masses of MoS_(2)on the surface of ZnIn_(2)S_(4)nanosheets by a simple photo-assisted deposition method.The morphology,structure and properties of the materials were analyzed by X-ray diffraction(XRD),scanning electron microscopy(SEM),X-ray energy spectrometry(EDS),UV-vis diffuse reflectance(UV-vis DSR),and electrical properties measurement.It can be observed that ZnIn_(2)S_(4)nanosheets are richer in active sites than bulk ZnIn_(2)S_(4),and the MoS_(2)/ZnIn_(2)S_(4)composite photocatalyst exhibits excellent light absorption utilization,significant increase in photocurrent intensity,notable reduction in impedance and remarkable improvement in photogenerated carrier separation efficiency,compared with ZnIn_(2)S_(4)nanosheets photocatalyst.When the mass ratio of MoS_(2)is up to 3%,the average hydrogen evolution rate of MoS_(2)/ZnIn_(2)S_(4)photocatalyst achieves the optimum level of 17.346 mmol·g^(-1)·h^(-1)under the irradiation of 300 W xenon lamp with light source AM1.5,which is 3.35 times of the that of pure ZnIn_(2)S_(4)nanosheets and 13.55 times of bulk ZnIn_(2)S_(4).And its performance can maintain above 90%with outstanding stability after three cycles.Therefore,the construction of MoS_(2)/ZnIn_(2)S_(4)photocatalytic system can effectively improve the photocatalytic performance of single photocatalyst ZnIn_(2)S_(4).