基于晶格失配应力和表面缺陷协同调控的高效铁电复合光催化剂的构建与性能研究

Photocatalytsis can utilize solar energy to degrade pollutant and split water into hydrogen, and it is regarded to be an ideal technology to solve the environmental pollution and energy shortage. Ferroelectric semiconductor photocatalysts have attracted considerable attentions due to its ability for the separation of photogenerated charges. In this project, ferroelectric composite nanoparticles with core/shell structure with ferroelectric photocatalysts (BaTiO3and BiFeO3) as shell phase and appropriate materials (MgO、SiO2and LaAlO3) as core phase are prepared by soft-chemistry route, and the surface defects are introduced on the obtained composite nanoparticles via a chemical reduction route. We will realize the enhancement of polarization of ferroelectric photocatalysts and promotion the bulk migration of photogenerated charges through the lattice mismatch stress between core/shell phases. Reducing the bandgap of ferroelectric photocatalysts and improving the surface migration rate of photogenerated charges through the introduction of the surface defects. We aim to develop efficient ferroelectric composite photocatalysts with wide light response range. We will clarify the influence of the structure parameters on the lattice mismatch stress, polarization, separation efficiency of photogenerated charges and photocatalytic properties. This project is expected to develop a novel method for the further improvement of the overall photocatalytic properties of ferroelectric photocatalysts.

光催化技术可以利用太阳能降解污染物和分解水制氢，被认为是解决环境污染和能源短缺的理想技术。铁电半导体光催化剂作为一类对光生电荷具有分离功能的光催化材料已成为该项技术关注的焦点。. 本项目以铁电光催化材料(钛酸钡和铁酸铋)为研究对象，选用合适的内核材料(氧化镁、二氧化硅和铝酸镧)，通过软化学法实现铁电光催化材料对内核颗粒的包覆，获得具有核/壳结构特征的铁电复合纳米颗粒，随后采用化学还原法在复合纳米颗粒表面引入缺陷。利用核/壳两相间晶格失配应力增强铁电光催化材料的极化强度，达到促进光生电荷体相迁移的目的；通过引入表面缺陷，减小铁电光催化剂带隙同时加快其光生电荷表面迁移。研发出高效且光响应范围广的铁电复合光催化剂。同时揭示材料结构参数对晶格失配应力、极化强度、光生电荷分离效率和光催化性能的影响规律，为进一步全面提高铁电光催化剂的催化性能探索出新途径。

光催化技术被认为是一种解决环境污染和能源短缺的理想“绿色”技术。本项目以BaTiO3，SrTiO3，BiFeO3和Bi2O3等半导体光催化剂为研究对象。由于这些光催化剂中光生电荷复合率较高和带隙较宽，限制了其实际应用。因此，本项目采取多种策略对其进行改性，从而提高其光催化性能。分别利用引入表面氧空位和构建核/壳结构复合物的方法改性BiFeO3，增强了光生电荷的分离效率以及对可见光的吸收。在表面氧空位和碳量子点(CQDs)修饰的协同作用下，对Bi2O3的光催化性能进行全面提高。构建Ⅱ型g-C3N4/BiFeO3和p-n型Ag3PO4/BiFeO3异质结，为提高BiFeO3中光生电荷的分离效率探索出新的改性策略。通过组建Z型异质结Ag2S/BiFeO3，研发出光催化效率高、光响应范围广且光催化氧化还原能力强的BiFeO3复合光催化剂。分别利用Au纳米颗粒和BiVO4对BaTiO3进行复合改性研究，实现光生电荷分离效率以及光吸收效率的提升。同样对SrTiO3进行Au纳米颗粒的修饰改性，提高光催化效率。采用多种测试技术和手段，对产物的物相、晶体结构，表面元素化学态、微观形貌、光响应范围、带隙以及光生电荷行为开展系统表征。分别采用有机染料和苯酚作为目标降解物，研究了模拟太阳光、可见光和近红外光照射下产物的光催化降解活性。探明了各种改性和修饰策略对光催化剂的改性规律，揭示了材料的构成、微观形貌、晶体结构、表/界面性质与光生电荷分离效率、光吸收范围、光催化性能之间的关系。基于实验结果提出了可能的光催化降解机理。.在本项目经费的支持下，截止到项目结题为止已在SCI期刊发表论文10篇，EI期刊发表论文1篇，授权实用新型专利1件，申请实用新型专利1件，申请发明专利2件。参加学术会议2次，培养硕士研究生2名。