过渡金属水氧化催化剂结构与催化机理的理论研究

项目名称： 过渡金属水氧化催化剂结构与催化机理的理论研究

项目编号： No.21503018

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 李熙琛

作者单位： 北京师范大学

项目金额： 21万元

中文摘要： 发展高效稳定的水氧化催化剂对提高“太阳能–燃料”转化效率至关重要。2011年，孙立成等报道了已知体系中速率最快的单核Ru水氧化催化剂，催化活性接近自然界光系统II中的放氧复合物。然而，对其“结构–性质”关系和反应历程的微观探索尚处于初步阶段。发展基于第一周期过渡金属的水氧化催化剂具有经济意义。近年来，Nocera等报道了基于Co–氧基和Ni–氧基的无定型簇合物体系，在室温和近pH中性的温和条件下有可观的反应速率和良好的自恢复特性。然而，原位X射线吸收光谱等实验只能给出关于Co–/Ni–氧基簇合物体系稳定态和活化态几何结构的间接数据，对于反应历程中体系氧化态的变化和关键O–O化学键生成步的研究也存在着争议。本项目针对上述Ru体系和Co–/Ni–氧基簇合物体系，使用密度泛函理论对催化反应势能面开展系统的研究，基于量子力学/实验谱联用精修，准确计算体系的结构参数，阐释催化剂高效稳定的内在驱动力。

中文关键词： 水氧化；过渡金属氧化物；密度泛函理论；EXAFS精修；质子耦合电子转移

英文摘要： The development of efficient and stable water oxidation catalyst is crucial to improve the Solar energy - fuel conversion efficiency. In 2011, Sun Licheng et al reported a mononuclear Ru water oxidation catalyst that has by far the fastest catalytic rate, even comparable to the oxygen evolving complex in photosystem II in nature, among artificial water oxidation catalysts. However, the study of the structure-property relation and the reaction pathway at the microscopic level is still rather preliminary. The development of water oxidation catalysts based on the first row transition metals have economic advantages. In the past few years, Nocera et al reported the amorphous Co-oxo and Ni-oxo cluster systems which have good performance under mild conditions, i.e., room temperature and near neutral pH, and extraordinary self-healing capabilities. However, experiments such as in situ X-ray absorption spectroscopy only gave indirect information concerning the topology of the resting state and the activated state of the systems. The assignments of the oxidation states along the reaction pathway and the proposal of the key O-O bond formation transition state are also controversial. This project aims to find the root cause for the high efficiency and stability of the above Ru system and Co-oxo/Ni-oxo cluster systems by investigating systematically the reaction potential energy surface using the density functional theory and assigning accurately structural parameters based on combined quantum mechanics/experimental spectra refinement.

英文关键词： water oxidation;transition metal oxide;density function theory;EXAFS refinement;proton coupled electron transfer