多元金属氧化物有序多孔薄膜的设计构筑及其精细光场调控特性与光解水性能研究

The conflict between long efficient light absorption depth and short charge-carrier diffusion lengths of most metal oxides based photo¬electrodes, seriously blocks the enhancement of their photoelectrochemical water splitting performance；the ordered porous film has the potential to combine the superiorities of high optical absorption and short carriers diffusion length, is thus highly anticipated to be employed as “optical” thick and “electrical” thin photoelectrode film. Examplified by the multinary metal oxides, we will explore in this project the application of colloids crystal template strategy in the construction of ordered porous film with finely-tuned optical fields, to balance the optical and electrical competition within the photoelectrode film based on the strengthen and widen optical absorption of single-layered porous structure. This project will systematically investigate the influences of the structural parameters (such as morphology, array period, aspect ratio, and the ratio of pores in binary hetero-apertured structures) on the finely-tuned optical fileds, will set up the relationship spectrum bewteen the porous structures and enhanced optical fields, will explore the modulation of photoelctrochemical performance enhancement based on the fabricated 2D ordered porous film, and will clarify the mechanism between performance enhancement and fine-tuned ordered structures. The smooth implementation of the project, is anticipated to provide theoretical basis as well as the key fundamental materials for the design of high performance multinary metal oxides based photoelectrodes, and also is of scientific significance forthe development and application of photoelectrode water splittings.

传统的金属氧化物光电极薄膜普遍存在高吸收效率所需的长光程与短的光生载流子扩散长度之间的矛盾，严重制约了光电化学水分解性能的提升。有序多孔膜兼具强光捕获与短距离载流子传输的优势，有望用做“光学”厚、“电学”薄的薄膜光电极。本项目拟选择多元金属氧化物材料，采用单层胶体晶体模板技术构筑具有精细光学调控特性的有序多孔膜，利用单层孔结构的强光捕获与宽谱吸收特性，解决薄膜光电极中光学与电学之间的矛盾；研究多孔阵列结构中孔的形状、纵横比、周期、以及双元异径孔结构中不同孔尺寸之间的比率等对光学精细调控的影响规律，建立微观结构-光场增强构效关系图谱，探寻二维纳米有序多孔膜对光电化学水分解性能调控的规律，阐明性能与结构间的相互影响机制，提高光电化学水分解效率。该项目的实施，将为设计高性能多元金属氧化物薄膜光电极提供理论依据；为光电化学水分解奠定核心关键材料基础，对光电化学水分解的开发应用具有重要意义。

本项目重点研究了半导体金属氧化物纳米薄膜的可控制备、电子结构调控及其光解水性能。针对低的载流子迁移率、高的光生载流子复合率，以及缓慢的析氧反应动力学而表现出较低的光电化学性能这些难题，寻求并构筑高性能的有序孔结构和金属纳米晶修饰的薄膜光电极，获得了常规条件不易获得的高性能纳米材料，将贵金属颗粒、引入金属氧化物母体和有序多孔膜的构筑，创制了异于原子掺杂的、母体材料电子结构及载流子动力学调控的独特有效途径，最终获得光电流密度达到较高的光电化学水分解材料。此外，拓展发展了有序多孔钒酸铋薄膜的制备及其在气体传感器中的应用，为光解水及其他热电转化材料提供了独特结构调控思路及性能优化途径。受本项目资助的工作，已经发SCI收录论文14篇，包括Nature Communications、Journal of Materials Science & Technology、Chemical Engineering Journal、Journal of power sources 等高水平期刊，申请并授权专利2项。代表性研究成果总结如下：.（1）制备：以聚苯乙烯球为模板，构筑了形态可控的氧化铁单一和双孔径有序多孔薄膜；基于光热瞬态极端条件的液相脉冲激光辐照技术可控制备了粒径可控的钒酸铋胶体颗粒，利用同样的技术还制备了贵金属Pt纳米晶。.（2）光电化学水分解研究：利用TiO2晶界修饰，梯度Ti掺杂等策略制备了高性能的氧化铁光电极薄膜。制备了Ti3C2-MXene修饰的Nb-Fe2O3纳米阵列、Pt纳米晶-FeOOH修饰的Fe2O3光电极、碳量子点修饰以及MnOx-Ar等离子修饰的钒酸铋复合光阳极。.（3）拓展研究：探索了等离子体表面修饰对BiFeO3半球形有序阵列、有序多孔钒酸铋薄膜和激光辐照的钒酸铋微结构在气敏传感器领域的应用。