Li Dayu, Xu Kai, Zhang Chao
School of Mechanical Engineering, Yangzhou University, Yangzhou 225009, China.
Nanomaterials (Basel). 2022 Nov 5;12(21):3906. doi: 10.3390/nano12213906.
In this study, multiple heterojunction structures of anatase-rutile/Bismuth oxyiodide (BiOI) composite fibers are designed by the combined method of electrospinning and hydrothermal techniques. The influence of different Ti/Bi atomic ratios ([Ti/Bi]) on the nanostructures and photocatalytic properties are investigated. It is found that the morphology of BiOI covered on the TiO fiber surface changed with [Ti/Bi] from nanosheets to submicron spheres structures. Additionally, the crystallization of the composite fibers including the phases of anatase, rutile, and BiOI is identified, theses phases are in close contact with each other, and the interfacial effects are helpful to form the multiple heterojunctions which lead to blue shifts on the chemical state of Ti. The absorption of visible light has been improved by compositing BiOI on TiO, while the band gap values of the composite fibers are significantly reduced, which can enhance the generation and separation of electrons and holes. For the case of [Ti/Bi] = 1.57, the photodegradation rate of anatase-rutile/BiOI composite fibers is about 12 times that of pure TiO. For the photocatalytic mechanism, the synergistic s-type heterojunctions increase the content of active oxides which have a positive effect on the degradation rate.
在本研究中，通过静电纺丝和水热技术相结合的方法设计了锐钛矿-金红石/碘氧化铋（BiOI）复合纤维的多种异质结结构。研究了不同Ti/Bi原子比（[Ti/Bi]）对纳米结构和光催化性能的影响。发现覆盖在TiO纤维表面的BiOI的形貌随[Ti/Bi]的变化从纳米片变为亚微米球结构。此外，确定了复合纤维的结晶情况，包括锐钛矿、金红石和BiOI相，这些相彼此紧密接触，界面效应有助于形成多个异质结，从而导致Ti的化学状态发生蓝移。通过在TiO上复合BiOI提高了可见光吸收，同时复合纤维的带隙值显著降低，这可以增强电子和空穴的产生与分离。对于[Ti/Bi]=1.57的情况，锐钛矿-金红石/BiOI复合纤维的光降解速率约为纯TiO的12倍。对于光催化机理，协同的s型异质结增加了活性氧化物的含量，这对降解速率有积极影响。
