磷酸根离子对α-Fe2O3表面负静电场强度以及形貌调控规律研究

项目名称： 磷酸根离子对α-Fe2O3表面负静电场强度以及形貌调控规律研究

项目编号： No.21503147

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 有机化学

项目作者： 王红艳

作者单位： 天津理工大学

项目金额： 21万元

中文摘要： 本项目根据磷酸盐与alpha氧化铁以及β-FeOOH之间强吸附作用原理，通过水热合成方法制备磷酸根修饰的超薄纳米块氧化铁薄膜光电极，应用于光电催化分解水体系。通磷酸盐的加入达到对薄膜电极进行表面修饰和形貌调控的双重目的。对磷酸根引发氧化铁纳米块形成机理进行深入研究，通过形貌调控，制备有利于光生电子与空穴有效分离与传输的超薄氧化铁纳米块薄膜电极，充分缩短电子向导电玻璃以及空穴向氧化铁/电解质界面传输的距离，减少体相中的电子空穴复合几率；对磷酸根表面修饰的作用机理进行深入研究，阐明磷酸根与氧化铁的结合方式以及结合位点数量对表面负静电场强度的影响规律，通过调节负静电场强度，达到延长光生空穴寿命，促进光生电荷向电解液/氧化铁界面的定向迁移，实现电荷的有效分离和传输。为实现太阳能转化提供理论基础和技术支持。

中文关键词： alpha氧化铁薄膜；光电化学；水分解；磷酸盐；形貌控制

英文摘要： This study will develop a facile method for a better photoelectrochemical performance of hematite thin films, which combines the morphology control and surface modification together by tuning the absorption and reaction conditions between phosphate and the precursors of hematite. Nanocube structured ultrathin hematite films will be prepared, based on the strong absorption effects between phosphate and hematite or β-FeOOH, which will be used as photoanodes in photoelectrochemical water splitting system. A nanocube structured ultrathin hematite film will reduce the hole migration and the electron transfer distances from the bulk of hematite to the surface and FTO glass respectively, which will minimize bulk charge recombination efficiently. The influence of the phosphate ions on the morphology of hematite will be studied in detail. The mechanism for the formation of the nanocube structure will be investigated systematically. ..An electrostatic field could be built up through the surface negative electrical charge, which will facilitate photoexcited hole migration and injection to the electrolyte solution, leading to efficient charge separation. The phosphate ions may form a bidentate complex or monodentate complex on the surface of hematite, depending on different absorption conditions, which will form a negative electrostatic field when isoelectric point of the hematite film is lower than the pH of the electrolyte. A thorough study on the influence of the nature and amount of the complex on the strength of negative electrostatic field and the charge separation yields will be made. It is expected that the results of this research will provide theoretical basis and technical support for solar energy conversion.

英文关键词： Hematite film;Photoelectrochemical;Water splitting;Phosphate;Morphology control