高界面密度异质结多孔微纳米复合陶瓷纤维膜的构建及其在水流振动波作用下压电光催化增强机理研究

The built-in electric field was formed by the self polarization of ferroelectric materials that can promote the separation of photogenerated holes and electrons in semiconductors after the combination of ferroelectric materials and semiconductor photocatalysts. However, the static built-in electric field is easy to be generated by the carrier shielding, thus gradually losing effects of promoting carriers separation, resulting in a short period of enhanced photocatalytic properties. Therefore, it is great significance that how to improve the strength of the built-in electric field and ensure its continuous regeneration in the photocatalytic process. This project proposes fabricating porous micro-nano composite ceramic fibrous membranes with high interfacial density heterojunctions by electrospinning. Flow vibration waves with different frequencies are applied to fibers in photocatalytic experiments to simulate wastewater treatment aeration or ultrasonic cavitation process in the photocatalytic experiment, then the micro deformation of fibers will cause periodic change of built-in electric field. The continuous enhancement of light and force as well as piezoelectric coupling photocatalytic effects was obtained. Structure-activity relationship between the built-in electric field, interfacial density of heterojunctions of geometric sizes of porous micro-nanofiber membranes and their photocatalytic performances and spectral response range are revealed. Promotion mechanisms of the flow vibration wave on alternating changes of the built-in electric field in fiber membranes and promoting the separation of hole and electron are explained. It is provide theoretical and experimental basis for development and application of high performance photocatalytic materials.

铁电陶瓷与半导体光催化剂复合后，铁电陶瓷自极化形成的内建电场可以促进半导体界面上光生空穴和电子的分离，但是静态的内建电场易被不断产生的载流子屏蔽，从而失去继续促进载流子分离的作用，导致光催化的增强效果短暂，所以研究如何提高内建电场强度并保证其反复再生对于增强光催化性能具有重要的意义。本项目提出基于静电纺丝技术构建具有高界面密度异质结的压电光催化多孔微纳米复合纤维膜，在光催化实验时施加不同频率的水流振动波模拟污水处理的曝气或超声空化过程，使纤维发生微变形引起内建电场周期性变化，结合光生电和力生场协同作用实现持续增强的光-力-压电耦合光催化效果。揭示多孔微纳米复合陶瓷纤维膜的内建电场、异质结界面密度和几何尺寸与其光催化性能和光谱响应范围的构效关系，阐明水流振动波对纤维膜内建电场交替变化以持续促进空穴和电子分离的作用机制，为高性能光催化材料的开发和应用提供理论和实验基础。

铁电陶瓷与半导体光催化剂复合后，铁电陶瓷自极化形成的内建电场可以促进半导体界面上光生空穴和电子的分离，但是静态的内建电场易被不断产生的载流子屏蔽，从而失去继续促进载流子分离的作用，导致光催化的增强效果短暂，所以研究如何提高内建电场强度并保证其反复再生对于增强光催化性能具有重要的意义。本项目提出基于静电纺丝技术构建具有高界面密度异质结的压电光催化多孔微纳米复合纤维膜（高界面密度BaTiO3/ZnO复合纳米纤维膜、可控界面密度KNbO3/TiO2复合纳米纤维膜等），获得组分比例和制备工艺等对纤维膜物相组成、微观形貌、比表面积、压电性能及光催化性能的影响规律，从载流子的分离与复合率的视角揭示了异质结界面密度与几何尺寸对复合纤维膜内建电场、压电光催化性能等的影响规律。在光催化实验时施加不同频率的水流振动波模拟污水处理的曝气或超声空化过程，使纤维发生微变形引起内建电场周期性变化，分析了异质结多孔微纳米复合纤维膜的疲劳特性和循环稳定性，包括长时间服役对纤维膜组成、微观结构、压电光催化性能的影响。揭示了复合纤维膜中压电材料与光催化剂的复合形式在超声波作用下产生变形行为所诱导的内建电场对压电光催化性能的促进机制，阐明了双压电增强效应高效促进载流子分离的促进机制，澄清了低能量水流振动波作用下产生动态压电场对光催化性能的促进机制，实现光-力-压电耦合增强光催化效果；为高性能光催化材料的开发和应用提供理论和实验基础。