Department of Civil and Environmental Engineering, University of Texas at San Antonio, San Antonio, TX, USA.
Department of Physics and Astronomy, The University of Texas at San Antonio, San Antonio, TX, USA.
J Colloid Interface Sci. 2019 Apr 1;541:234-248. doi: 10.1016/j.jcis.2019.01.082. Epub 2019 Jan 22.
Different morphologies and crystal phases of black titanium dioxide (TiO) were synthesized using Pulsed Laser Ablation in Liquid (PLAL). The synthesized laser modified black TiO (LMB-TiO) structures included hydrogenated anatase TiO nanoparticles, as the core shell structures, and TiO microspheres. TiO core-shell nanoparticles, which had crystalline-disordered structures, demonstrated the laser ablation pulse duration-dependence growth of amorphous shells and hence formation of disordered TiO nanoparticles with different thickness of hydrogen-doped amorphous shells were shown. TiO microspheres with the yolk-shell like structures (YSHL-TiO microspheres), on the other hand, showed the formation of rutile phases in the shell which encapsulate Lattice Expanded Planes (LEPs) in the core. The microspheres demonstrated phase transitions from anatase to rutile and size-dependent lattice interlayers expansion from 0.35 nm to 0.94 nm. The maximum particle size growth occurred when the samples were subjected to the laser ablation for 120 min. The crystal phase transition, consequently, led to the formation of heterostructured photocatalysts through construction of hydrogenated anatase TiO nanoparticles junctions with rutile TiO microspheres. The photocatalytic degradation of methylene blue (MB) using LMB-TiO heterostructure was tested under visible light irradiation Results showed approximately 99% of MB was degraded after 60 min. Enhanced visible light absorption and increased charge carrier lifetime due to formation of different types of heterojunctions may explain the higher photocatalytic performance of LM-TiO samples. Moreover, the Photoluminescence analysis indicated that hydroxyl radicals were the main active species involved in the photocatalytic degradation tests and therefore the photocatalysis mechanism was accordingly suggested.
采用脉冲激光烧蚀液相法（PLAL）合成了不同形貌和晶相的黑色二氧化钛（TiO）。所合成的激光改性黑色 TiO（LMB-TiO）结构包括氢化锐钛矿 TiO 纳米粒子作为核壳结构和 TiO 微球。具有非晶结构的 TiO 核壳纳米粒子表现出激光烧蚀脉冲持续时间依赖性的非晶壳生长，因此形成了具有不同厚度氢化非晶壳的无序 TiO 纳米粒子。另一方面，具有蛋黄壳样结构（YSHL-TiO 微球）的 TiO 微球在壳中表现出金红石相的形成，壳中包裹着晶格扩展平面（LEPs）在核中。微球表现出从锐钛矿到金红石的相转变以及从 0.35nm 到 0.94nm 的层间晶格的尺寸依赖性扩展。当样品受到激光烧蚀 120min 时，最大粒径增长发生。晶体相转变导致通过构建氢化锐钛矿 TiO 纳米粒子与金红石 TiO 微球的异质结，形成了异质结构光催化剂。在可见光照射下，使用 LMB-TiO 异质结构对亚甲基蓝（MB）进行了光催化降解测试。结果表明，60min 后，MB 的降解率约为 99%。由于形成了不同类型的异质结，增强了可见光吸收和增加了载流子寿命，这可能解释了 LM-TiO 样品具有更高的光催化性能。此外，光致发光分析表明，羟基自由基是参与光催化降解测试的主要活性物质，因此提出了相应的光催化机制。
