The State Key Laboratory of Refractories and Metallurgy, School of Materials and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, China.
The State Key Laboratory of Refractories and Metallurgy, School of Materials and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, China.
J Colloid Interface Sci. 2018 Mar 15;514:496-506. doi: 10.1016/j.jcis.2017.12.061. Epub 2017 Dec 24.
As an n-type semiconductor with an excellent physicochemical properties, iron oxide (FeO) has been extensively used in the fields of environmental pollution control and solar energy conversion. However, the high recombination rate of the photoinduced electron-hole pairs and poor charge mobility for FeO nanomaterial generally result in low photocatalytic efficiency. Herein, an uniform CdS nanorods grown directly on one-dimensional α-FeO nanotube arrays (NTAs) are successfully synthesized by a facile hydrothermal method and the constructed heterojunction can be a kind of efficient and recyclable photocatalysts. Successful deposition of CdS nanorods onto the α-FeO NTAs is verified by field emission scanning electron microscopy(FESEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM) with energy dispersive X-ray spectroscopy (EDS). UV-Vis diffuse reflectance spectroscopy indicates that α-FeO/CdS NTAs possess the intense visible light absorption and also display a red-shift of the band-edge compared with the pure α-FeO NTAs. The as-obtained α-FeO/CdS NTAs display excellent photocatalytic activity for decomposition of methylene blue (MB), methyl orange (MO), and phenol under visible light illumination. Among all the tested photocatalysts, the film synthesized for 3h with good stability exhibits the best photocatalytic properties and produces the highest photocurrent of 1.43 mA/cm at 0.8 V vs. Ag/AgCl electrode, owing to its well formed heterojunction structure, effective electron-hole pair separation and direct electron transfer pathway along the CdS nanorods and α-FeO NTAs. Besides, the photogenerated holes (h) and superoxide radicals (O) play dominant roles in the photocatalytic process. On the basis of the photocatalytic results and energy band diagram, the photocatalytic process mechanism is proposed. Considering the easy preparation and excellent performance, α-FeO/CdS NTAs could be a promising and competitive visible-light-driven photocatalyst in the field of environment remediation.
作为一种具有优异物理化学性质的 n 型半导体，氧化铁（FeO）已广泛应用于环境污染控制和太阳能转换领域。然而，FeO 纳米材料的光生电子-空穴对复合率高和电荷迁移率差通常导致其光催化效率低。在此，通过简便的水热法成功合成了一维α-FeO 纳米管阵列（NTAs）上直接生长的均匀 CdS 纳米棒，所构建的异质结可以作为一种高效且可回收的光催化剂。场发射扫描电子显微镜（FESEM）、X 射线衍射（XRD）和透射电子显微镜（TEM）以及能谱（EDS）证实了 CdS 纳米棒成功沉积在α-FeO NTAs 上。紫外可见漫反射光谱表明，与纯α-FeO NTAs 相比，α-FeO/CdS NTAs 具有强烈的可见光吸收，并表现出带边红移。所获得的α-FeO/CdS NTAs 在可见光照射下对亚甲基蓝（MB）、甲基橙（MO）和苯酚的分解表现出优异的光催化活性。在所测试的所有光催化剂中，具有良好稳定性的合成 3h 的薄膜表现出最好的光催化性能，并在 0.8V 对 Ag/AgCl 电极时产生 1.43mA/cm 的最高光电流，这归因于其形成良好的异质结结构、有效电子-空穴对分离以及沿着 CdS 纳米棒和α-FeO NTAs 的直接电子转移途径。此外，光生空穴（h）和超氧自由基（O）在光催化过程中起主要作用。基于光催化结果和能带图，提出了光催化过程机制。考虑到其易于制备和优异的性能，α-FeO/CdS NTAs 可能是一种有前途且具有竞争力的可见光驱动光催化剂，可用于环境修复领域。
