Nanojunction-Mediated Photocatalytic Enhancement in Heterostructured CdS/ZnO, CdSe/ZnO, and CdTe/ZnO Nanocrystals
Nanojunction-Mediated Photocatalytic Enhancement in Heterostructured CdS/ZnO, CdSe/ZnO, and CdTe/ZnO Nanocrystals
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DOI：
10.1002/anie.201404481
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发表时间：
2014-07-21
影响因子：
16.6
通讯作者：
Tsang, Shik Chi Edman
中科院分区：
文献类型：
--
作者：
Eley, Clive;Li, Tong;Tsang, Shik Chi Edman
通过生长纤锌矿-氧化锌四面体，制备了一系列高效半导体纳米晶(NC)光催化剂。两个小但高质量的晶体之间的接触产生了具有广泛的第二类纳米结的新颖的CDX/ZnO异质结构半导体纳米晶(HSNCs)，在紫外光照射下表现出更有效的光催化分解水中有机分子。催化性能测试和表征表明，硫系阴离子的本征化学性质和异质结结构共同作用提高了催化剂的催化活性。首次利用原子探针层析(APT)研究了硫化物镉与氧化锌晶体之间纳米结的空间特性，揭示了两种晶体之间不同程度的离子交换，以缓解较大的晶格失配。在最极端的情况下，由于界面合金化的结果，观察到了由于界面合金化而被氧化锌完全包裹的CdTe，预期的优点是促进了空穴传输，从而在催化过程中增强了激子的分离。
A series of highly efficient semiconductor nanocrystal (NC) photocatalysts have been synthesized by growing wurtzite-ZnO tetrahedrons around pre-formed CdS, CdSe, and CdTe quantum dots (QDs). The resulting contact between two small but high-quality crystals creates novel CdX/ZnO heterostructured semiconductor nanocrystals (HSNCs) with extensive type-II nanojunctions that exhibit more efficient photocatalytic decomposition of aqueous organic molecules under UV irradiation. Catalytic testing and characterization indicate that catalytic activity increases as a result of a combination of both the intrinsic chemistry of the chalcogenide anions and the heterojunction structure. Atomic probe tomography (APT) is employed for the first time to probe the spatial characteristics of the nanojunction between cadmium chalcogenide and ZnO crystalline phases, which reveals various degrees of ion exchange between the two crystals to relax large lattice mismatches. In the most extreme case, total encapsulation of CdTe by ZnO as a result of interfacial alloying is observed, with the expected advantage of facilitating hole transport for enhanced exciton separation during catalysis.