Xia Weiwei, Sun Jiawei, Zeng Xianghua, Wang Pengdi, Luo Min, Dong Jing, Yu Huaguang
College of Physics Science and Technology & Institute of Optoelectronic Technology, Yangzhou University, Yangzhou 225002, P. R. China.
College of Electrical, Energy and Power Engineering, Yangzhou University, Yangzhou 225127, P. R. China.
ACS Omega. 2020 Feb 3;5(5):2205-2213. doi: 10.1021/acsomega.9b03197. eCollection 2020 Feb 11.
As one of the most promising photoanode materials for photoelectrochemical (PEC) water oxidation, earth-abundant hematite has been severely restricted by its poor electrical conductivity, poor charge separation, and sluggish oxygen evolution reaction kinetics. FeO has an ability to produce hydrogen, while its preparation needs high temperature to reduce Fe to Fe by using H or CO gases. Here, FeO- and FeO-based nanorods (NRs) on fluorine-doped tin oxide (FTO) substrate have been prepared, where the latter was obtained by doping Sn ions in FeOOH to reduce Fe ions to Fe. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) measurements indicate that the dominant content of Fe element on the surface of Sn-doped FeO and Sn-FeOOH samples is Fe. FeO-based NRs have a FeO/FeO heterostructure with some SnO nanoparticles distributed on their surface. These prepared samples were used as PEC photoanodes under a visible-light irradiation. The results showed that the modified FeO-based NRs have a photocurrent density of 0.2 mA cm at 1.23 V vs reference hydrogen electrode (RHE) using Hg/HgO electrode as the reference electrode. Furthermore, they also have a better photocatalytic hydrogen evolution activity with a rate of 2.3 μmol h cm. The improved photocurrent and photocatalytic activity can be ascribed to the Sn-dopant, as the introduction of Sn not only leads to the formation of the FeO/FeO heterostructure but also increases the carrier concentration. FeO/FeO heterostructure with SnO nanoparticles on its surface has a good band energy alignment, which is beneficial to the PEC water oxidation and reduction.
作为用于光电化学（PEC）水氧化最有前景的光阳极材料之一，储量丰富的赤铁矿因其导电性差、电荷分离不佳以及析氧反应动力学迟缓而受到严重限制。FeO具有产氢能力，但其制备需要高温，通过使用H或CO气体将Fe还原为Fe。在此，已在氟掺杂氧化锡（FTO）衬底上制备了基于FeO和FeO的纳米棒（NRs），其中后者是通过在FeOOH中掺杂Sn离子将Fe离子还原为Fe而获得的。X射线衍射（XRD）和X射线光电子能谱（XPS）测量表明，Sn掺杂的FeO和Sn-FeOOH样品表面Fe元素的主要含量为Fe。基于FeO的NRs具有FeO/FeO异质结构，其表面分布有一些SnO纳米颗粒。这些制备的样品在可见光照射下用作PEC光阳极。结果表明，使用Hg/HgO电极作为参比电极，改性的基于FeO的NRs在相对于参比氢电极（RHE）为1.23 V时的光电流密度为0.2 mA cm²。此外，它们还具有更好的光催化析氢活性，速率为2.3 μmol h⁻¹ cm⁻²。光电流和光催化活性的提高可归因于Sn掺杂剂，因为Sn的引入不仅导致形成FeO/FeO异质结构，还增加了载流子浓度。表面带有SnO纳米颗粒的FeO/FeO异质结构具有良好的能带能量排列，这有利于PEC水氧化和还原。
