Ta3N5 nanotubes and -rods: doping, band-gap engineering and stabilization (co-catalysis)

目前的研究项目解决了基于太阳能的水的光电解，使用一维（1D）形式的潜在高活性半导体作为光吸收剂和能量转换器，直接从水中产生氢气和氧气。由一维纳米结构X：Ta 3 N5光阳极（X：改性）组成的光阳极将作为一类新的光催化剂进行研究。由于相对合适的小带隙（~2.1 eV）和带边位置，Ta 3 N5将作为进一步修饰的平台。这项工作的关键创新将是开发理想结构和掺杂的Ta 3 N5纳米管/纳米棒，通过本体掺杂和表面催化剂进行改性，以大幅提高其效率。这里使用的纳米结构是基于低成本的阳极自组织过程或水热方法，这样的纳米管/纳米棒具有高表面积、定向电荷传输、电荷载流子扩散长度量级的尺寸以及原位嵌入掺杂物质（带隙工程）的能力的固有关键优势。此外，为了减轻光腐蚀问题，X：Ta 3 N5结构将被新开发的电荷转移催化剂修饰，例如NiFe层状双氢氧化物层。最近，我们的团队开发了一种方法来生长纳米级Ta 3 N5结构，用合适的催化剂装饰，以获得水分解效率的10倍增加，以及在W掺杂的Ta 3 N5上的第一个结果（将带隙降低到1.75 eV）。在拟议的项目中，这些初步发现将得到系统性的跟进--通过研究材料的性质与自排列纳米管/纳米棒Ta 3 N5的生长形态、掺杂和优化及其通过新型助催化剂的稳定性的关系。

The present research project tackles solar-based photoelectrolysis of water, using potentially highly active semiconductors in one dimensional (1D) form as the light absorber and energy converter to directly produce hydrogen and oxygen from water. Photoanodes consisting of a 1D nanostructured X:Ta3N5 photoanode (X: modified) will be investigated as a new category of photocatalysts. Due to the relatively suitable small band gap (~2.1 eV) and band edge positions, Ta3N5 will serve as a platform for further modification. Key innovation in this work will be the development of ideally structured and doped Ta3N5 nanotubes/nanorods, modified by bulk doping and surface catalysts to drastically increase their efficiency. The nanostructures used here are based on low cost anodic self-organization processes or on a hydrothermal method, such nanotubes/nanorods have the intrinsic key advantages of a high surface area, directional charge transport, dimensions in the order of charge carrier diffusion length, and the ability to in-situ embed doping species (band-gap engineering). Additionally, in order to alleviate the photocorrosion problem, X:Ta3N5 structures will be decorated with newly developed charge transfer catalysts, such as NiFe layered double hydroxide layers. Recently, our group developed an approach to grow a nanoscale Ta3N5 architecture decorated with suitable catalysts to obtain a 10-fold increase in water splitting efficiency as well as first results on W doped Ta3N5 (shifting the band gap down to 1.75 eV). These preliminary findings will, within the proposed project, be systematically followed up - by studying the properties of the material as a function of growth-morphology, doping, and optimization of self-arranged nanotubular/nanorod Ta3N5 and its stabilization by novel co-catalysts.