Li Naixu, Zhang Longzhou, Zhou Jiancheng, Jing Dengwei, Sun Yueming
School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, P.R. China.
Dalton Trans. 2014 Aug 14;43(30):11533-41. doi: 10.1039/c4dt00969j. Epub 2014 May 30.
Nanosized photocatalysts have been shown to be important to many modern photocatalytic reactions. Control of the microstructure of the nanocrystals enables regulation of their optical properties and enhancement of specific reactions. Here, Cu(2+)-doped ZnS nanosphere photocatalysts with hierarchical nanostructures and controllable sizes were synthesized via a facile wet-chemical reaction. We demonstrated that small amounts of Cu(2+) doping could give rise to the formation of a variety of localized, nanosized Cu(1-x)Zn(x)S solid solutions that are separated by a continuous ZnS medium. The nano-solid-solutions have predictable band structures and an average size of several nanometers, which ensure facile generation of electron-hole pairs by visible light irradiation and quick migration of the photo-generated charges to the interfaces. With Ru as a cocatalyst, the as-prepared 0.5 mol% Cu(2+)-doped ZnS nanospheres showed a high H2 evolution rate of 1.03 mmol h(-1), corresponding to a quantum efficiency of 26.2% at 425 nm. A hierarchical surface structure with a large surface area is considered crucial for the increased activity. Our work not only showed that the non-toxic metal chalcogenides achieve high efficiency but also provides a new concept of localized nano-solid-solution for photocatalytic applications.
纳米尺寸的光催化剂已被证明对许多现代光催化反应至关重要。控制纳米晶体的微观结构能够调节其光学性质并增强特定反应。在此，通过一种简便的湿化学反应合成了具有分级纳米结构和可控尺寸的Cu(2+)掺杂ZnS纳米球光催化剂。我们证明，少量的Cu(2+)掺杂能够导致形成多种由连续的ZnS介质分隔的局域化纳米尺寸的Cu(1-x)Zn(x)S固溶体。这些纳米固溶体具有可预测的能带结构且平均尺寸为几纳米，这确保了通过可见光照射能够轻松产生电子 - 空穴对，并使光生电荷快速迁移到界面。以Ru作为助催化剂，所制备的0.5 mol% Cu(2+)掺杂的ZnS纳米球显示出1.03 mmol h(-1)的高析氢速率，对应于在425 nm处26.2%的量子效率。具有大表面积的分级表面结构被认为对活性的提高至关重要。我们的工作不仅表明无毒金属硫族化物能够实现高效率，还为光催化应用提供了一种局域化纳米固溶体的新概念。
