基于TiO2复合结构的光催化基元过程模拟和析氢活性调控研究

Photocatalysis shows great potential applications in the fields of energy and environment. However, because of the complicated process, it remains challenging to clarify the catalytic nature and tailor the activity of photocatalytic reactions. In this project, we select five distinct composite structures (Pt/TiO2, Pd/TiO2, Ni/TiO2, 1T-MoS2/TiO2, 2H-MoS2/TiO2) as the representative models, take the photocatalytic hydrogen evolution reaction (HER) as the study case, and by resorting to various of theoretical methods such as the ab initio molecular dynamics, the hybrid functional calculations, and the microkinetic modeling, we focus on the following research contents: i) systematically examining the contribution weight of numbers of geometric/electronic parameters of composite catalysts on each elementary process in photocatalytic HER (the light absorption, photoelectric charge transport, surface catalytic hydrogen production), and illuminating the key physical parameters and inherent laws affecting the photocatalytic performance; ii) subsequently investigating the modulation effect of many chemical modification methods (such as the metal alloying, ion doping, construction of vacancy sites, surface ligand adsorption etc.) on the key parameters; iii) regulating the photocatalytic HER activity of cheap materials (e.g. Ni/TiO2、MoS2/TiO2) as guided by those key parameters, and attempting to propose optimized strategies (or combinations) of modification/regulation methods, and to provide theoretical support and direction for the development of highly efficient catalysts for photocatalytic hydrogen production.

光催化技术在能源环境领域具有重大应用前景，但其过程复杂性使得阐明催化机理和调控活性面临诸多挑战。本项目拟选取Pt/TiO2、Pd/TiO2、Ni/TiO2、1T-MoS2/TiO2、2H-MoS2/TiO2五种结构迥异的代表性界面复合结构模型，借助从头算分子动力学、杂化泛函计算、微观动力学等理论方法，以光催化析氢反应（HER）为研究示例，（1）系统性考查复合催化剂多种几何/电子结构参数对于光催化HER各基元过程（光吸收、光电荷输运、表面催化析氢）的贡献权重，阐明影响光催化性能的关键物性参数和内在规律；（2）继而探究金属合金化、离子掺杂、构建空缺位、表面配体吸附等化学改性方法对关键物性参数的调变作用；（3）针对Ni/TiO2、MoS2/TiO2等廉价材料开展以关键物性参数为导向的光催化HER活性调控研究，提出优化的改性/调控方法组合策略，为高效光催化析氢催化剂的开发提供理论依据和方向。

由于复合光催化材料结构及光催化多基元过程的双重复杂性，如何阐明光催化机理、确立动力学速控因素、进而实现催化材料理性设计构筑，成为挑战性科学难题。项目借助从头算分子动力学、杂化泛函计算、微观动力学等理论计算方法，重点围绕负载型TiO2光催化HER以及更复杂的NO3-RR、OER等体系，从催化机理及速控因素解析、化学改性与调控机制、光催化材料优化设计，三个方面开展了系统深入且有序递进的理论研究，取得了如下重要结果：（1）阐明了光催化各基元过程（光吸收、光电荷输运、表面催化）的关键影响因素；光吸收和电荷输运效率分别与体系的禁带宽度、电荷转移热力学、金属/氧化物界面隧穿势垒、能级位置密切相关，而HER、NO3-RR、OER的表面催化反应速控步骤分别为H-H耦合、NH*/NH2*加氢、·OH自由基生成。（2）揭示了金属合金化、金属/非金属离子掺杂、氧空缺位、表面配体吸附等化学改性方法对复合催化剂多种几何/电子结构参数（电荷密度、化学价态、隧穿势垒、能级位置、热力学势）的调变作用。（3）提出了增强光催化活性的有效策略，理论预测Pt/Cu/TiO2、Pt/Zn-TiO2、Pt/Cu-TiO2、N/Ov-TiO2等多种高效低成本光催化材料。项目实施三年，以第一/通讯作者发表标注本基金号SCI学术论文9篇，包括Nature Communications 1篇、ACS Catalysis 3篇、Small 1篇等IF>10论文5篇，培养博士、硕士研究生各1名，项目负责人入选上海市科学技术委员会“启明星”计划。项目整体进展顺利，保质保量地完成了所制定的研究目标。