Abstract:

The Ag:ZnIn₂S₄ nanosheets were grown internal and external surface of hollow In₂O₃ microtubes, with the reasonable design and construction of a visible light-responsive In₂O₃/\mathrm{A}\mathrm{g}:\mathrm{Z}\mathrm{n}\mathrm{I}{\mathrm{n}}_{\mathrm{2}}{\mathrm{S}}_{\mathrm{4}}_{tubular heterostructure photocatalysts. The samples were prepared by a low-temperature oil bath method to ensure the uniform distribution of each component. Experimental preparation process: firstly, In(NO3)3 and 1,4-benzenedicarboxylic acid were dissolved in N,N-dimethylformamide (DMF) and placed in a low-temperature oil bath to obtain the precursor In-MIL-68. To synthesize the hexagonal In2O3 microtubes, In-MIL-68 was placed in a crucible, and then kept at a constant temperature of 500℃ for 2 h in a muffle furnace. Growth of Ag:ZnIn2S4 nanosheets on both inner and outer surfaces of In2O3 microtubes was achieved by a low temperature hydrothermal method. X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-visible diffuse reflection spectroscopy (UV-Vis DRS), and photoelectric chemical analysis (PEC) were used to investigate the phase, morphology, elemental combination state and light response characteristics of photocatalysts. After rigorous comparison and analysis, the optimized In2O3/40.0%(mass) \mathrm{A}\mathrm{g}:\mathrm{Z}\mathrm{n}\mathrm{I}{\mathrm{n}}_{\mathrm{2}}{\mathrm{S}}_{\mathrm{4}} sample exhibited an excellent rate of H2 production (21.85 μmol·h^-1) under visible light irradiation, which was 57.5 times and 1.5 times higher than that of pure In2O3 (0.38 μmol·h^-1) and Ag:ZnIn2S4 (14.79 μmol·h^-1). Simultaneously, in the experiment of MO degradation under visible light irradiation, the photodegradation rate of In2O3/40.0% Ag:ZnIn2S4 was 0.3466 min^-1, about 105 times and 2.1 times of In2O3 (0.0033 min^-1) and Ag:ZnIn2S4(0.1669 min^-1), respectively. These improvements are because of synergetic effect of compact heterojunction by unveiling a greater number of catalytically active sites and effectively enhancing charge-carrier separation and relocation. This is mainly attributed to the “Type Ⅱ” heterostructure formed between In2O3 and Ag:ZnIn2S4, which promotes the rapid migration and separation of photogenerated carriers.}

Key words: catalyst, composites, degradation, hydrogen production, ZnIn₂S₄, In₂O₃

摘要：

采用低温油浴的方法，制备出具有“Type Ⅱ”异质结构的In₂O₃/Ag:ZnIn₂S₄复合材料光催化剂。使用X射线粉末衍射（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、X射线光电子能谱（XPS）、紫外-可见漫反射光谱（UV-Vis DRS）以及光电化学测试（PEC）等技术对物相、形貌结构、元素化合状态、光响应特性等方面进行探究。在可见光照射下进行光解水制氢和光降解甲基橙（MO）实验来评价光催化剂的光催化活性，结果表明，粉末状光催化剂 In₂O₃/40.0%（质量分数）Ag:ZnIn₂S₄的光催化制氢速率达到 21.85 μmol·h^-1，约是In₂O₃和Ag:ZnIn₂S₄的57.5倍和1.5倍。在可见光下的降解MO实验中，In₂O₃/40.0% Ag:ZnIn₂S₄光降解速率为0.3466 min^-1，分别约是In₂O₃和Ag:ZnIn₂S₄的105倍和2.1倍。这主要归因于In₂O₃和Ag:ZnIn₂S₄之间形成的“Type Ⅱ”异质结构，促使光生载流子的快速迁移和分离。

关键词: 催化剂, 复合材料, 降解, 制氢, ZnIn₂S₄, In₂O₃