基于SrTiO3单晶纳米粒子固态Z型体系的定向制备及其光催化分解水研究

It is difficult for SrTiO3 to possess wide range light-absorption and provide energetic photo-induced charge carriers to drive water redox process simultaneously, which is the bottleneck for its application in photocatalytic water splitting. To solve this problem, this project proposes to targetedly synthesize solid-state Z-scheme system through directionally doping different facets of SrTiO3 and sequentially depositing solid-state electron mediator (e.g. Au, Ag etc.) and oxygen evolution photocatalyst (OEP, e.g. WO3, BiVO4) on the doped facets. Thus, the hydrogen evolution photocatalyst (HEP, i.e. SrTiO3) and OEP could be properly and tightly coupled via solid-state electron mediator. In this project, we will systemically study the intrinsic relationship between the doped facets of SrTiO3, the size and distribution of electron mediator/OEP and the photocatalytic activities of new Z-scheme system. With these studies, we can reveal the effects of doping elements on the band energy structure of different facts and spatial charges separation in SrTiO3, and elucidate transport mechanism of photo-induced charge carriers through the heterojunction interface between different facets, solid-state electron mediator and OEP. This project would propose a new controllable method for synthesis of photocatalysts with high efficiency. The expected results from these studies will provide theoretical basis and experimental reference for targeted synthesis of high-performance photocatalysts.

SrTiO3光催化材料难以同时具备宽光谱响应和强氧化还原H2O能力，是限制其光解水制氢的瓶颈。针对这一问题，本项目提出通过晶面定向掺杂SrTiO3，并将Au、Ag等固态电子传输介质及WO3或BiVO4等产氧半导体依次沉积在掺杂后SrTiO3的不同晶面，构建固态Z型体系，使产氢半导体（HEP，即SrTiO3）与产氧半导体（OEP，如WO3、BiVO4）通过电子传输介质紧密耦合，实现其可见光分解纯水制氢。系统研究掺杂晶面及SrTiO3不同晶面上电子传输介质/OEP的尺度和分布与其光催化性能之间的内在联系，揭示掺杂元素对SrTiO3晶面能带结构和光生电荷定向分离传输的影响规律，阐明光生载流子在不同晶面-电子传输介质-产氧半导体之间异质结界面处的传输机制及其催化反应动力学过程，建立一种高性能光催化材料的可控合成新方法。研究结果将为定向设计和合成高性能光催化剂提供理论依据和实验参考。

太阳能光催化制氢技术能够以H2O为原料，通过纳米半导体光催化材料吸收太阳光将其分解为H2和O2，把太阳能直接转换为化学能储存于H2中，为解决当前环境污染和能源短缺等问题提供了重要契机。目前制约光催化材料效率不高的原因主要在于光生电荷复合严重和表面催化反应动力学慢。针对该问题，本项目在执行期内围绕钛酸锶等异质结与固态Z型体系光催化材料开展了相关工作，研究了固态Z型体系光催化材料与异质结构筑方法，阐明了其结构、能带、电荷传输与分离对其光催化性能之间的影响规律，揭示了Z型体系光催化材料及异质结界面处能带匹配对光生载流子迁移的定向传输机制，顺利地完成了本项的研究内容和关键问题。