Layer-by-Layer Self-Assembly of CdS Quantum Dots/Graphene Nanosheets Hybrid Films for Photoelectrochemical and Photocatalytic Applications
Layer-by-Layer Self-Assembly of CdS Quantum Dots/Graphene Nanosheets Hybrid Films for Photoelectrochemical and Photocatalytic Applications
复制标题
DOI：
10.1021/ja411651e
复制
发表时间：
2014-01-29
影响因子：
15
通讯作者：
Liu, Bin
中科院分区：
文献类型：
--
作者：
Xiao, Fang-Xing;Miao, Jianwei;Liu, Bin
近年来，石墨烯半导体纳米复合材料作为高效光催化剂的应用越来越受到人们的关注。不幸的是，制备具有可控膜厚度和结构的均匀石墨烯-半导体复合膜仍然具有挑战性，这对于满足应用要求至关重要。在本工作中，通过在存在下原位还原剥离的氧化石墨来制备稳定的聚合物修饰的石墨烯纳米片（GNs）的水分散体。阳离子聚烯丙胺盐酸盐（PAR）。所得水溶性PAH改性GN。利用纳米结构单元（GNs-PAH）与定制的带负电荷的CdS量子点（QD）结合，通过有序的层层自组装（LbL）方法制备了良好定义的GNs-CdS QD杂化膜，其中CdS QD均匀地分布在二维（2D）GNs上。结果发现，与纯CdS量子点和GNs薄膜相比，交替GNs-CdS量子点多层膜在可见光照射下表现出显着增强的光电化学和光催化活性。这种增强归因于CdS量子点与GNs以交替方式明智地整合，这最大化了GNs CdS-QD复合膜中GNs的2D结构优势。此外，还对GNs-CdS量子点多层膜的光催化和光电化学机理进行了探讨。我们的工作有望为制备具有广泛应用前景的均匀半导体/纳米晶杂化薄膜开辟新的方向。
In recent years, increasing interest has been devoted to synthesizing-graphene semiconductor nanocomposites as efficient photocatalysts for extensive applications. Unfortunately, it is still challenging to make uniform graphene-semiconductor composite films with controllable film thickness and architecture, which are of paramount importance to meet the application requirements. In this work, stable aqueous dispersion of polymer-modified graphene nanosheets (GNs) was prepared via in situ reduction of exfoliated graphite oxide in the presence of. cationic poly(allylamine hydrochloride) (PAR). The resultant water-soluble PAH-modified GNs. (GNs-PAH) in conjunction with tailor-made negatively charged CdS quantum dots (QDs) were utilized as nanobuilding blocks for sequential layer-by-layer (LbL) self-assembly of well-defined GNs-CdS QDs hybrid films, in which CdS QDs overspread evenly on the two-dimensional (2D) GNs. It was found that the alternating GNs-CdS QDs multilayered films showed significantly enhanced photoelectrochemical and photocatalytic activities under visible light irradiation as compared to pure CdS QDs and GNs films. The enhancement was attributed to the judicious integration of CdS QDs with GNs in an alternating manner, which maximizes the 2D structural advantage of GNs in GNs CdS-QDs composite films. In addition, photocatalytic and photoelectrochemical mechanisms of the GNs-CdS QDs multilayered films were also discussed. It is anticipated that our work may open new directions for the fabrication of uniform semiconductor/GNs hybrid films for a wide range of applications.