Abstract Decorating ZnO with nanosheets of MoS2—a transition metal dichalcogenide characterized by a relatively narrow band gap—is a promising way to increase the photocatalytic activity of ZnO. However, limited studies report the effect of the layer number of of MoS2 nanosheets on the photocatalytic performance of ZnO/MoS2. In this work, ZnO nanorods were decorated with multilayer and few-layer (~11 and ~3 atomic layers) MoS2 nanosheets exfoliated for 4 h and 8 h, respectively. This type-II heterostructures were subsequently used as photocatalysts for the degradation of methyl blue. Our results show that the photocatalytic efficiency of the ZnO/MoS2 was less than that of pristine ZnO and it further decreased by 11% with increasing the number of layers and length of the MoS2 nanosheets. This effect may be due to the decrease of adsorption capacity of the water molecules on the ZnO/MoS2 system as indicated by the increasing contact angle from 17o–23o to 73o–76o. The increase in contact angle for ZnO/MoS2 could be due to the hydrophobic nature of the basal plane of the 2H-MoS2 phases, which are called inactive catalytic sites.

中文翻译：

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MoS2纳米片层数对ZnO/MoS2光催化效率的影响

摘要 用 MoS2 纳米片装饰 ZnO 是一种具有相对窄带隙的过渡金属二硫属化物，是提高 ZnO 光催化活性的一种很有前景的方法。然而，有限的研究报告了 MoS2 纳米片的层数对 ZnO/MoS2 光催化性能的影响。在这项工作中，ZnO 纳米棒装饰有多层和少层（~11 和~3 个原子层）MoS2 纳米片，分别剥离了 4 小时和 8 小时。这种II型异质结构随后被用作降解甲基蓝的光催化剂。我们的结果表明，ZnO/MoS2 的光催化效率低于原始 ZnO，并且随着层数和 MoS2 纳米片长度的增加，其光催化效率进一步降低了 11%。这种效应可能是由于水分子对 ZnO/MoS2 系统的吸附能力降低，如接触角从 17o-23o 增加到 73o-76o 所表明的。ZnO/MoS2 接触角的增加可能是由于 2H-MoS2 相基面的疏水性，称为非活性催化位点。