Zhang Yaozhong, Mandal Rajib, Ratchford Daniel C, Anthony Rebecca, Yeom Junghoon
Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI 48823, USA.
Department of Mechanical Engineering, Michigan State University, East Lansing, MI 48824, USA.
Nanomaterials (Basel). 2020 Mar 9;10(3):491. doi: 10.3390/nano10030491.
Numerous semiconductor-based hybrid nanostructures have been studied for improved photodegradation performance resulting from their broadband optical response and enhanced charge separation/transport characteristics. However, these hybrid structures often involve elements that are rare or toxic. Here, we present the synthesis and material characterization of hybrid nanostructures consisting of zinc oxide (ZnO) nanowires (NWs) and silicon nanocrystals (Si-NCs), both abundant and environmentally benign, and evaluate them for photodegradation performance under various illumination conditions. When incorporating Si-NCs into the vertically-aligned ZnO NWs immobilized on substrates, the resulting photocatalysts exhibited a narrowed band gap, i.e., more responsive to visible light, and enhanced charge separation at the interface, i.e., more reactive species produced for degradation. Consequently, the hybrid Si-NCs/ZnO-NWs displayed a superior photodegradability for methylene blue under UV and white light in comparison to the pristine ZnO NWs. Based on the optical measurements, we hypothesize the band structures of Si-NCs/ZnO-NWs and the potential mechanism for the improved photodegradability.
许多基于半导体的混合纳米结构因其宽带光学响应和增强的电荷分离/传输特性而被研究用于改善光降解性能。然而，这些混合结构通常涉及稀有或有毒元素。在此，我们展示了由氧化锌（ZnO）纳米线（NWs）和硅纳米晶体（Si-NCs）组成的混合纳米结构的合成及材料表征，这两种材料都储量丰富且对环境无害，并评估了它们在各种光照条件下的光降解性能。当将Si-NCs掺入固定在基板上的垂直排列的ZnO NWs中时，所得光催化剂的带隙变窄，即对可见光的响应更强，并且界面处的电荷分离增强，即产生更多用于降解的活性物种。因此，与原始的ZnO NWs相比，混合的Si-NCs/ZnO-NWs在紫外光和白光下对亚甲基蓝表现出优异的光降解性。基于光学测量，我们推测了Si-NCs/ZnO-NWs的能带结构以及光降解性改善的潜在机制。
