Ferreira Nilson S, Sasaki José M, Silva Romualdo S, Attah-Baah John M, Macêdo Marcelo A
Departamento de Física, Universidade Federal de Sergipe, 49100-000 São Cristóvão, SE, Brazil.
Laboratório de Corrosão e Nanotecnologia (LCNT), Universidade Federal de Sergipe, 49100-000 São Cristóvão, SE, Brazil.
Inorg Chem. 2021 Apr 5;60(7):4475-4496. doi: 10.1021/acs.inorgchem.0c03327. Epub 2021 Mar 12.
Defect influences on the photoactivity of ZnO nanoparticles prepared by a powdered coconut water (ACP) assisted synthesis have been studied. The crystalline phase and morphology of ZnO nanoparticles were effectively controlled by adjusting the calcination temperature (400-700 °C). An induced transition of hybrid Zn(CO)(OH)/ZnO nanoparticles to single-phase ZnO nanoparticles was obtained at 480 °C. The morphological analysis revealed a formation of ZnO nanoparticles with semispherical (∼6.5 nm)- and rod-like (∼96 nm) shapes when the calcination temperatures were 400 and 700 °C, respectively. Photoluminescence characterizations revealed several defects types in the samples with and being in the self-assembly of semispherical- and rod-like ZnO nanoparticles. The photocatalytic activity of the ZnO nanoparticles was examined by assessing the degradation of methylene blue in an aqueous solution under low-intensity visible-light irradiation (∼3 W m). The results point toward the self-assembly of semispherical- and rod-like ZnO nanoparticles that had significantly better photocatalytic activity (∼31%) in comparison to that of spherical-agglomerated- or near-spherical-like species within 120 min of irradiation. The possible photocatalytic mechanism is discussed in detail, and the morphology-driven intrinsic [+] defects are proposed to be among the active sites of the ZnO nanoparticles enhancing the photocatalytic activity.
研究了缺陷对通过粉末状椰子水（ACP）辅助合成制备的ZnO纳米颗粒光活性的影响。通过调节煅烧温度（400 - 700°C）有效地控制了ZnO纳米颗粒的晶相和形态。在480°C时获得了混合的Zn(CO)(OH)/ZnO纳米颗粒到单相ZnO纳米颗粒的诱导转变。形态分析表明，当煅烧温度分别为400°C和700°C时，形成了半球形（约6.5 nm）和棒状（约96 nm）形状的ZnO纳米颗粒。光致发光表征揭示了样品中的几种缺陷类型， 和 存在于半球形和棒状ZnO纳米颗粒的自组装中。通过评估在低强度可见光照射（约3 W m）下亚甲基蓝在水溶液中的降解来检测ZnO纳米颗粒的光催化活性。结果表明，在120分钟的照射时间内，半球形和棒状ZnO纳米颗粒的自组装具有比球形团聚或近球形颗粒明显更好的光催化活性（约31%）。详细讨论了可能的光催化机理，并提出形态驱动的本征[+]缺陷是增强ZnO纳米颗粒光催化活性的活性位点之一。
