水氧化性能增强导向的氧化铟表界面调控与掺杂的理论研究

The photoelectrochemical (PEC) water splitting by visible light using semiconductor material is a challenging and profound project in the field of energy materials. The water oxidation is regarded as one of the key issues in achieving efficient PEC water splitting. In recent years, doping and surface engineering of semiconductor photoelectrodes have became intriguing fields, as they are important strategies of obtaining different physicochemical properties to optimize the PEC properties of semiconductor photoelectrodes. However, the atomic-level understanding of oxygen evolution reaction on the exposed crystal facets of metal oxides with d10 configuration has not been established. In this project, we will take In2O3 as an example to carry out an extensive theoretical study of band structure engineering and surface water oxidation reaction based on density functional theory calculations and molecular dynamics simulations. Our activities including the following three parts: (1) Manipulate the electronic structures and optical properties of bulk In2O3 by monodoping or codoping with various metal cations and non-metal anions, and provide new strategies of doping for enhanced visible-light photoactivity. (2) Determine the surface phases of In2O3 {001}, {110}, and {111} surfaces in contact with water through explicitly considering the adsorption behavior of both molecular H2O and dissociated H2O on each surface at different coverages. Based above results, determine the rate-controlling steps and overpotential of water oxidation on different surfaces of In2O3, analyse the reason of high overpotential, understand the effect of surface structures on the activity of the water oxidation. (3) Explore the effect of surface codoping and interface structures on the performance of water oxidation of In2O3 {001} surface, understand and predict some engineering ways toward possible control over surface reactivity. These theoretical results and predictions would not only gain our insight into the water oxidation mechanisms of In2O3, but also be helpful and useful for designing and applying photoanode materials with high performance in the near future.

能源材料领域中一个重大研究课题就是基于光催化剂如何有效利用太阳能分解水制氢。其中水氧化是一个至关重要的反应，因为它制约着产氢效率。尽管人们发现通过掺杂和暴露活性表面可以提高水分解活性，但对水如何在d10光电极材料的活性表面上逐步氧化成氧气的微观机理的理解尚不够深入。本项目拟将采用密度泛函理论和分子动力学模拟等多种方法，对In2O3这种具有d10电子构型的光电极材料开展深入的理论研究，包括：1、对块体材料进行各种单或共掺，优化体系的能带结构以实现其光反应性能增强；2、研究In2O3{001}、{110}、{111}面上的水氧化反应，确定不同表面上水氧化反应的决速步骤和过电位，理解影响过电位高低的本质原因，揭示水氧化性能增强的表面调控机理；3、探讨如何通过表面共掺以及界面调控降低In2O3{001}面水氧化反应过电位，提高水氧化性能。本项目的实施将为研发高性能光电极材料提供一些理论依据和指导。

针对光催化分解水领域面临的几个关键问题，我们利用第一性原理计算和分子动力学等理论手段，经过三年来的系统和深入的研究，取得一些研究进展，并顺利完成预期目标。目前已在Phys. Chem. Chem. Phys., Int. J. Hydrogen Energy, Nanotechnology, RSC Adv.等国内外学术期刊上发表SCI致谢论文11篇。主要的研究成果或进展包括：（1）利用非金属共掺杂（N + N，C + S，N + P）实现对宽带隙ZrO2体系能带工程的有效调控；（2）筛选出（Rh + F）表面共掺杂方式以及金属（Zn或Cd）相助的S-O耦合机制有效改性TiO2体系的电子结构，提升光反应活性；（3）理论预测了一系列二维光催化分解水材料（如单层II-VI金属硫化物和BiOI），发现这些材料的能级位置与带隙大小均可满足光解水产氢与产氧；（4）理论设计出可见光驱动的Z型C3N/g-C3N4光催化体系。显然，这些研究成果为开发新型的光解水材料的实验研究和应用研究提供有意义的理论依据和指导。此外，在项目执行期间，项目组成员参加国内外学术研讨会10余人次，合作指导硕士2名，本科毕业论文设计15人，目前在读硕士研究生3人。