Institute of Chemistry, Federal University of Mato Grosso do Sul, Av. Senador Filinto Muller, 1555, CP 549, CEP 79074-460-Campo Grande, MS, Brazil.
School of Physical Sciences, Dublin City University, Dublin 9, Ireland.
J Nanosci Nanotechnol. 2020 Feb 1;20(2):1177-1188. doi: 10.1166/jnn.2020.16961.
ZnO nanorods were grown on silicon (Si) substrates by two techniques: (i) Chemical Bath Deposition (CBD) and (ii) a CBD seed layer combined with Carbothermal Reduction Vapor Phase Transport (CTR-VPT). The structured ZnO nanorods were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and contact angle measurments. The photoelectrochemical property of ZnO nanorods were analyzed by linear voltammetry under UV-ABC light excitation. Using the ZnO nanorod samples as photoanodes, the removal of methylene blue (MB) as a representative organic compound was studied by the photoelectrocatalytic (PEC) technique applying a potential (E) of 0.6 V. For comparison purposes, experiments were performed under the same conditions using photocatalysis (PC), direct photolysis and using samples of pure Si (support material) as working electrodes in PEC. XRD analyses of ZnO prepared by both methods showed the expected ZnO wurtzite phase and a preferred c-axial orientation in the growth of the nanorods. The presence of ZnO was further confirmed by XPS and contact angle measurements showed that ZnO grown by CBD (ZnO/CBD) had a slightly hydrophobic behavior while ZnO grown by CTR-VPT (ZnO/CTR-VPT) is hydrophilic. Both ZnO sample types were shown to be photoactive, with ZnO/CBD showing higher resultant photocurrent compared to ZnO/CTRVPT. For the degradation of MB 53% of the compound was removed using ZnO/CBD as a working electrode, while using the ZnO/CTR-VPT electrode led to a removal of 43% of MB. However, direct photolysis alone removed 39% of the MB. The lower removal of MB using ZnO/CTR-VPT samples was related to surface dissociation during the degradation process. The results show that ZnO nanorods prepared by the CBD techique are a promising photoelectrode for PEC applications. Our data also indicate that CTR-VPT-grown nanorods produce uniform nanorod arrays, but this uniform nanostructure deposit does not lead to any increase in PEC activity.
氧化锌纳米棒在硅（Si）衬底上通过两种技术生长：（i）化学浴沉积（CBD）和（ii）CBD 种子层与碳热还原气相传输（CTR-VPT）的组合。结构氧化锌纳米棒通过扫描电子显微镜（SEM）、X 射线衍射（XRD）、X 射线光电子能谱（XPS）和接触角测量进行了表征。使用线性伏安法在 UV-ABC 光激发下分析了氧化锌纳米棒的光电化学性质。使用氧化锌纳米棒样品作为光阳极，通过施加 0.6V 的电势（E），通过光电催化（PEC）技术研究了亚甲基蓝（MB）作为代表性有机化合物的去除。为了比较目的，在相同条件下进行了实验，使用光催化（PC）、直接光解和使用纯 Si（支撑材料）作为工作电极的 PEC。两种方法制备的 ZnO 的 XRD 分析表明，预期的 ZnO 纤锌矿相和纳米棒生长中的优先 c 轴取向。XPS 和接触角测量进一步证实了 ZnO 的存在，表明 CBD 生长的 ZnO（ZnO/CBD）具有轻微的疏水性，而 CTR-VPT 生长的 ZnO（ZnO/CTR-VPT）具有亲水性。两种 ZnO 样品类型均表现出光活性，与 ZnO/CTR-VPT 相比，ZnO/CBD 表现出更高的光电流。对于 MB 的降解，使用 ZnO/CBD 作为工作电极去除了 53%的化合物，而使用 ZnO/CTR-VPT 电极去除了 43%的 MB。然而，单独的直接光解去除了 39%的 MB。使用 ZnO/CTR-VPT 样品去除 MB 的比例较低与降解过程中表面离解有关。结果表明，通过 CBD 技术制备的 ZnO 纳米棒是 PEC 应用的有前途的光电电极。我们的数据还表明，CTR-VPT 生长的纳米棒产生均匀的纳米棒阵列，但这种均匀的纳米结构沉积物不会导致 PEC 活性的任何增加。
