State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China.
Nanoscale. 2015 Mar 19;7(13):5767-75. doi: 10.1039/c4nr07343f.
The use of colloidal semiconductor nanocrystals (NCs), especially those with a core/shell structure, for photocatalytic hydrogen (H₂) production from water is currently one of the hottest research fields. Although the ligand on the semiconductor NC surface is crucial to the optical and optoelectronic properties of the NC, the study of the ligand effect on the photocatalytic activity of H₂ generation is rarely reported. Herein, we employ nearly monodispersed CdSe/CdS core/shell NCs as a model photocatalytic system, and three kinds of ligands with different numbers of functional thiol groups (i.e., poly(acrylic acid), 3-mercaptopropionic acid and 2,3-dimercaptosuccinic acid) are selected as the ligands to investigate the effect of ligand on the efficiency of H₂ photogeneration. The results show that the H₂ photogeneration efficiency is highly dependent on the surface ligand of the NCs, and it increases with the increase of the number of the functional thiol groups in the ligand, and correspondingly, the photoluminescence intensity and average fluorescence lifetime, which are measured by steady state and time-resolved fluorescence measurements, are decreased. The surface trap-related charge separation efficiency, which is mediated by surface coating with different ligands, is supposed to cause the distinct ligand-dependent performance in the H₂ evolution.
胶体半导体纳米晶体（NCs），特别是具有核/壳结构的 NCs，用于从水中光催化制氢（H₂），目前是最热门的研究领域之一。尽管半导体 NC 表面的配体对 NC 的光学和光电性能至关重要，但关于配体对 H₂生成光催化活性影响的研究却很少报道。在此，我们采用近单分散的 CdSe/CdS 核/壳 NCs 作为模型光催化体系，并选择三种具有不同数目的功能巯基的配体（即聚丙烯酸、3-巯基丙酸和 2,3-二巯基丁二酸）作为配体，研究配体对 H₂光生成效率的影响。结果表明，H₂光生成效率高度依赖于 NCs 的表面配体，且随配体中功能巯基数目的增加而增加，相应地，通过稳态和时间分辨荧光测量测得的光致发光强度和平均荧光寿命降低。通过不同配体表面包覆来介导的表面陷阱相关电荷分离效率，导致了在 H₂演化中明显的配体依赖性性能。
