氧化铟/金属硫族化合物纳米管阵列异质结的构筑与光电化学制氢性能

The performance of photoanode materials is one of the most importance factors for photoelectrochemical cells. How to obtain type II heterostructures with high absorption efficiency of visible light and transporting efficiency of photo-generated charge-carrier transportation which are composed of tradition-metal oxide with wide-bandgap and metal chalcogenide with narrow-bandgap has attracted considerable attention. Indium oxide (In2O3) is of great interest due to its excellent photoelectrochemical properties. However, the design of type II heterostructures based on Indium oxide is limited due to its the negative conduction band potential. Based on the above discussion, we can regulate the donor densities in order to improve its photoelectrochemical properties and adjust the conduction band position. The thermal decomposition behavior of In(OH)3 and the design of one-dimensional nanostructures is beneficial for introducing oxygen vacancies into In2O3. Therefore, in this project, we will focus on the design and synthesis of nanotube heterojuctions exhibiting type II feature and its electrochemical properties, which is composed of In2O3 and metal chalcogenide with narrow-bandgap. This approach is on the basis of the In2O3 nanotubes with appropriate band structure which is fabricated by `template of ZnO nanorod arrays in the electrochemical depsosition and thermal treatement. This work is aimed to elucidate the relationship between different morphologies, structures, compositions and photoelectrochemical properties of In2O3 based composites. We are sure that this project will not only provide a new insight to the large-scale preparation of high-performance photoanode materials, but also promote their practical applications in solar-driven photoelectrochemical cells.

光阳极材料是决定光电化学池性能的最重要因素之一，如何获得具有高的可见光吸收效率、光生载流子输运效率的宽禁带过渡金属氧化物-窄禁带金属硫族化合物II型异质结复合材料是目前的研究热点和难点。本项目针对In2O3性能优越但因导带能级较高而难以与其他窄禁带金属硫族化合物形成II型异质结构的问题，提出通过调控其浅施主杂质浓度在提升其光电化学性能的同时有效降低其导带能级位置这一策略，利用氢氧化铟热分解过程以及一维纳米结构在对调控氧空位浓度方面体现出的优势，在以一维氧化锌纳米棒为模板结合热处理法制备一维氧化铟纳米管的基础上实现In2O3/窄禁带金属硫族化合物纳米管阵列II型异质结的构筑及其光电化学析氢性能，并籍此深入研究复合材料的形貌，结构，组成与光电化学性能的内在联系，为开发和应用高性能的光阳极材料和光电化学池器件提供重要的理论依据与技术支持。

近年来，光电化学分解水制氢由于其能够利用太阳能来制备氢气能源而备受关注。而在该体系中，光阳极的设计对于光电化学性能显得尤为关键，因为它直接决定了太阳光的吸收效率和载流子的分离效率。有鉴于此，该项目主要设计和制备了In2O3@In2S3纳米方块，In2O3@In2S3@Ag纳米方块，CeO2@Ag@CdS纳米管阵列和CeO2@Ag@CdSe纳米管阵列四种重要的体系，并详细探讨了其光电化学性能和内在结构的关系。从中我们得到的，重要结果，关键数据等及其科学意义有：第一，氧空位浅施主能级的引入可以将过负的In2O3导带底电位拉低，从而实现了与In2S3形成了II型异质结。第二，In2O3@In2S3II型异质结对于提升体系的光电化学分解水性能起到了关键性的作用。第三， Ag的LSPR效应可以提高体系的光生载流子的产生数目。第四，Ag与二元复合物的复合界面可以提升体系的光生载流子分离效率。第五，一维纳米阵列材料由于具有大的长径比，高的比表面积等特点，所以在其作为光阳极材料时为其提供良好的电子收集即传输通道，从而提升光阳极材料的活性。本项目的成果在太阳能光电化学分解水制氢领域有着良好的应用前景，并且为产业化提供了内在结构规律，理论依据和技术支持。