A hierarchical cluster-model approach to understand the catalytic water splitting at calcium-manganese-oxide centers

用于理解钙锰氧化物中心催化水分解的分层聚类模型方法

基本信息

批准号：
300369766
负责人：
Professor Dr. Thorsten M. Bernhardt
金额：
--
依托单位：
Institut für Oberflächenchemie und Katalyse
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2016
资助国家：
德国
起止时间：
2015-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/300369766?language=en
关键词：
hierarchical cluster model approach understand

项目摘要

Nature realized the solar energy driven catalytic water splitting reaction with earth abundant metal oxides in the oxygen evolving complex in photosystem II. The catalytic center of this complex consists of a CaMn4O5 cluster embedded in protein ligands inside the thylakoid membrane of plants, algae, and cyanobacteria. In this project we aim to develop a new hierarchical approach to probe fundamental concepts of the water splitting reaction employing isolated, mass-selected calcium-manganese-oxide clusters as simplified models of the natural catalytic water splitting center. The reactions of these clusters with water (and other relevant ligands such as isotopically labeled water, O2, H2, etc.) will be systematically studied in a gas phase ion trap experiment as a function of the exact size and composition of the CaxMnyOz clusters (that is, of the complexity of the system). These investigations can provide direct experimental evidence for the ability of the different clusters to dissociate water and to mediate the catalytic formation of H2, O2, or H2O2. Kinetic experiments enable the postulation of the detailed reaction mechanisms and, in conjunction with first principles calculations, permit molecular level insight into the catalytic reactions. Furthermore, selected cluster systems will be investigated by infrared vibrational spectroscopy and ultraviolet/visible photodissociation spectroscopy in order to obtain experimental insight into the geometrical structure of the clusters. Based on all the obtained results it is envisaged to develop a conceptual framework that can provide guidelines for the rational design of calcium-manganese-oxide based catalysts for the splitting of water. In this respect the gas phase experiment offers the unique possibility to precisely control and tune important parameters which determine the catalytic water splitting abilities with hierarchically increasing complexity of the materials like the size of the catalytic center, the oxidation state of the involved manganese atoms, the contribution of the calcium atoms, and the geometrical structure of the active complex.

大自然意识到在光系统II中，太阳能驱动的催化水分裂反应与氧气中的丰富金属氧化物反应。该复合物的催化中心由嵌入在植物，藻类和蓝细菌类囊体膜内的蛋白质配体中的CAMN4O5簇组成。在这个项目中，我们旨在开发一种新的分层方法，以使用孤立的，质量选择的丙烷氧化钙氧化钙簇作为自然催化水分分裂中心的简化模型，以探测水分裂反应的基本概念。这些簇与水（以及其他相关的配体，例如同位素标记的水，O2，H2等）的反应将在气相离子陷阱实验中系统地研究，这是Caxmnyoz簇的确切大小和组成的函数（即系统复杂性的）。这些研究可以提供直接的实验证据，证明不同簇分离水并介导H2，O2或H2O2的催化形成的能力。动力学实验能够假定详细的反应机制，并结合第一原理计算，允许分子水平洞察催化反应。此外，将通过红外振动光谱和紫外线/可见的光解离谱来研究选定的簇系统，以便获得对集群几何结构的实验见解。基于所有获得的结果，它设想开发一个概念框架，该概念框架可以为基于钙的氧化钙的催化剂的合理设计提供指南，以分裂水。在这方面，气相实验为精确控制和调整重要参数提供了独特的可能性，这些参数确定了催化水分裂能力，并具有层次上增加的材料的复杂性，例如催化中心的大小，所涉及的锰原子的氧化状态，钙原子的贡献以及活性复合物的几何结构。