六方氮化硼纳米片光解水催化剂能带调控机制的理论探索

六方氮化硼（h-BN）纳米片是不含金属组分的新型二维晶体，在能源、催化等领域具有重要科学研究价值和应用前景。但其带隙太宽，不能吸收可见光，限制了其在太阳能光催化领域的应用。因此，有必要采用物理化学方法改性修饰h-BN，建立能带结构的设计方法，在原子/分子水平上调控半导体能带结构，在窄化带隙的同时，使其带边位置与目标反应的氧化-还原电势相匹配。本项目利用第一性原理方法，寻求新的碳掺杂策略，系统研究各种碳掺杂方式对h-BN材料能带结构的影响机制。最重要的目标在于对带边位置的精准调控，使其价带顶位置足够深，以满足光解水产氧半反应的热力学要求，从而进一步提高光解水产氧效率，并揭示碳掺杂h-BN材料表面光解水产氧半反应的活性中心、反应路径及控制过电势大小的关键因素等重要微观本质。该理论研究对指导实验设计并合成新型二维非金属光解水催化剂材料具有重要的理论价值和现实意义。

Hexagonal boron nitride (h-BN) nanosheet is a novel two-dimensional crystal without metal component and has important scientific research value and application prospect in the fields of energy, catalysis and so on. However, due to its wide band gap, h-BN is incapable of adsorbing visible light, limiting its applications in solar photocatalysis. In order to narrow its band gap and make the band edges matching the oxidation-reduction potentials of target reactions, it is necessary to modify h-BN by using physical and chemical methods. The design of energy bands should be guided by a sound theoretical strategy to regulate the energy band structures of semiconductors in the level of atom/molecule. In this project, by using first-principle methods, we will explore new strategies for carbon doping into h-BN by systematically studying the regulation mechanism of the energy band structures of h-BN materials by various carbon doping. The most important goal is to precisely control the band edges of h-BN and to make the position of valence band top deep enough to satisfy the thermodynamic requirement for the oxygen evolution reaction (OER) in water splitting. In addition, some important microscopic features such as active centers, reaction pathways and generation of the overpotential in the OER of water splitting on carbon doped h-BN materials will be also investigated. This research will help to better design and synthesize novel two-dimensional metal-free photocatalysts for water splitting.