石墨烯/超薄纳米晶三维界面构建及光解水应用

To construct friendly, low-cost and stable photoelectrochemical catalysis system has been very challenging and intensively studied in photoelectrochemical water splitting. Graphene is excellent electron acceptor with high chemical stability and facilitate the electron-hole separation which can be applied the potential co-catalysts for semiconductors. To date, most photochemical and photoelectrochemical systems based on graphene use direct growth of nanocrystals on surfaces of two-dimensional graphene sheets. However, these kinds of nanocomposites face the problems of having low electron-hole separation, stability and photogenerated electron transport. To overcome these problems, here we will construct three-dimensional interfaces between three-dimensional porous graphene and ultrathin nanocrystals to enhance the light absorption and the efficiency of visible light-driven photoelectrochemical water splitting. Through the construction of three-dimensional interfaces between three-dimensional porous graphene and ultrathin oxide nanocrystals such as ultrathin Fe2O3 and Cu2O nanocrystals, we can obtain high-efficiency visible light photoelectrodes for photoelectrochemical water splitting with enhanced light absorption, electron-hole separation, photoelectron transport and stability. We will also study the deep connections between the structures of interfaces and the performance of photoelectrochemical water splitting.

构建环境友好、廉价、稳定的光电化学催化体系一直是光电化学分解水的研究难点与热点。石墨烯是优异的电子受体，能够促进半导体材料中电子空穴分离，而且具有优异的化学稳定性，因此可作为半导体材料的共催化剂。目前大部分光化学与光电化学石墨烯/半导体的复合结构都基于直接在单片石墨烯二维表面上生长半导体纳米材料。但这种纳米复合材料在形成光电极时面临着光生电子空穴分离效率、稳定性与光生电子传递效率低等缺陷。为解决以上问题，本研究将构建一种三维多孔石墨烯/超薄纳米晶三维界面，在增加光吸收的同时提高光生电子传递效率，并用于增强可见光光电化学分解水的效率。通过构建新型三维多孔石墨烯构/可见光敏感的超薄氧化物纳米晶（三氧化二铁与氧化亚铜）三维界面，在增强光吸收的同时提高光生电子空穴分离、光生电子传递效率、与光电极稳定性，进而制备高效的可见光催化光电极用于光电化学分解水，并探究界面结构与光电化学分解水性能的关联规律。

随着社会对绿色能源的需求增加，催化分解水逐渐变成一个重要的新能源热点研究领域，其中催化剂是影响分解水性能的关键因素。本项目首先研究了三维石墨烯的制备，研究了不同生长条件包括模板、生长时间，甲烷流量、退火温度等对三维石墨烯结构的影响，为三维导电骨架为基础的分解水催化剂研究奠定了基础。我们进一步制备了三维石墨烯骨架与过渡金属氧化物纳米晶复合结构催化剂，并研究了其分解水催化性能。与纯的过渡金属氧化物纳米晶相比，三维石墨烯导电骨架极大的提高了催化剂分解水的催化性能。本研究提供了一种通用的调控三维石墨烯结构的方法，同时也发展了简易的构建三维石墨烯-过渡金属氧化物界面的方法，成功制备了多种三维石墨烯过渡金属氧化物纳米晶复合结构。相关的催化与光电催化分解水测试表明，与纯的氧化物纳米晶相比，三维复合结构能够极大地提升催化分解水的催化性能。因此，本研究对未来开发便宜的分解水催化材料及其广泛应用提供了重要的基础与支撑。