基于可见光响应TiO2纳米管构建双反应位点全分解水体系

Photocatalytic overall water splitting water to produce hydrogen and oxygen under sunlight is an improtant strategic issue, which have a very attractive future in solving the clean energy shortage and environment pollution. In our previous work， a kind of novel anatase TiO2 nanotubes was prepared by the dehydration of titania acid nanotubes under high temperature treatment. This novel TiO2 possess a large amount of single-electron-trapped- vacancy (SETOV) in bulk and is responsive to the visible light. In this project, a model of overall splitting water will be built basing on this novel TiO2 nanotubes. The novel TiO2 nanotubes were used as a micro-reactor, and construct different hydrogen or oxygen evolution active sites in and out the nanotubes. Through the model of overall water splitting based on double reactive sites loaded different cocatalyst, the parameters such as types, structure and size of cocatalysts on the influence of the capture efficiency of electrons and holes were studied. The influence of photocatalytic oxidation or reduction of water was studied further. This can make the reduction or oxidaztion of water proceed in and out the TiO2 nanotubes, restrain the inverse hydration reaction. This model can make the water spliiting reaction proceed on two different active sites, and prohibit the inverse reaction effectively. This project will play an improtant role in construction of double reactive sites model for water splitting, and understanding the vital role of the cocatalysts. The successfully implement of this project will have a new breakthrough in the filed of photocatalytic overall water splitting under sunlight.

利用太阳能光催化“全”分解水制氢是一个具有重要战略意义的课题，在洁净能源利用和环境保护方面具有诱人的前景。前期，我们以自制纳米管钛酸为前驱体，通过高温处理和支柱效应的方法分别得到了含有大量束缚单电子氧空位、具有可见光响应的锐钛矿相TiO2纳米管。本项目拟以该新型TiO2纳米管为主体，构建新型可见光催化全分解水模型，即以新型TiO2纳米管为微反应器，在管内、外分别构建不同的产氢产氧反应活性位点。通过在这类双活性位点全分解水模型上构建不同的助催化剂，考察不同类型、结构、尺寸的助催化剂对光生电子和空穴捕集效率的影响，研究其对光催化还原或氧化水反应的影响。这一模型可使光催化分解水的氧化和还原反应在不同的反应活性位点上进行，有效地阻止逆反应发生，使光催化分解水得以顺利进行。该项目对于构建双活性位点分解水产氢产氧模型和了解助催化剂在分解水中的作用机理具有重要研究价值，期望在可见光全分解水领域有所突破。

本项目针对太阳能光催化分解水这一具有重要战略意义的研究课题，提出采用纳米管钛酸为前驱体，构建以纳米管为主体的新型可见光催化分解水体系。首先研究了表面/体相氧空位对TiO2光催化产氢活性的影响，发现煅烧气氛对TiO2表面/体相氧空位的形成及光催化产氢性能具有较大的影响，且表面/体相氧空位的比例对TiO2光催化产氢性能也有一定影响。随后将晶面效应与调控氧空位比例相结合，发现二者之间的协同作用进一步促进了TiO2光催化产氢性能的提高。构建了g-C3N4 /TiO2 Z-体系，并研究了其可见光催化性能，发现 N掺杂形式对g-C3N4 /TiO2 Z-体系可见光催化活性具有明显的影响，0D/1D界面层的构建可有效促进g-C3N4纳米颗粒/TiO2纳米管阵列Z体系光电催化分解水性能的进一步提高。采用改性分子筛Ti-MCM-41实现了CO2的高效光催化还原，通过表面修饰技术进一步提高了其转换效率。通过在海胆状中空TiO2纳米材料内外表面分别负载Pt和RuO2纳米颗粒实现了光解水析氢，进而通过还原处理在海胆状中空TiO2纳米材料引入表面Ti3+和体相氧空位，实现了海胆状中空黑色TiO2纳米材料的可见光分解水产氢的目标。最后，采用空间分离双助催化剂和光热协同效应实现了海胆状中空TiO2纳米材料可见光分解水性能的进一步提高。