Photoelectrocatalysis with Porous Coordination Polymers - Architectural Design, Morphology Control and Transport Properties

该项目的总体目标是建立一个集成的金属有机框架（MOF）光电催化水分解平台，以克服颗粒系统中普遍存在的牺牲供体/受体方案的需要。因此，我们的方法通过阐明和控制基于卟啉连接体的生物启发的MOF助催化剂混合结构中的光驱动电荷传输和氧化还原催化的基本原理，解决了MOF催化剂和电催化之间未知的界面。设计高效光电化学电池的先决条件将是开发（i）具有光捕获和电子通信子单元的高度多孔的MOF系统，以及（ii）用于高质量均质、取向的MOF薄膜电极的合成策略。我们的方法将通过固态NMR光谱和阻抗光谱对MOF薄膜的结构，动力学，光学特性和电子以及离子传输特性的见解以及光诱导氧化还原过程的（光）电化学分析来指导，反馈到设计循环中以创建具有高活性的氢和氧释放的MOF光电极，降低过电位和长期稳定性。为了完成这项高度跨学科的任务，B的研究小组。V.洛奇，M。T. Elm和J. Senker在结构和传输特性的合成和表征方面补充了他们的技能。Lotsch集团在MOF纳米材料的合成、MOF薄膜的生长及其对MOF的合成后改性方面拥有长期的专业知识。Lotsch团队将开发基于光活性卟啉和芘的MOF系统，该系统将与分子和非均相助催化剂相结合，以协调光诱导的多电子氧化还原过程，并浇铸成高质量的薄膜结构。对于MOF架构的结构阐明，Senker小组将提供大量最先进的NMR晶体学策略。他的小组将开发一种薄膜NMR探针，以分析MOF膜的结构完整性和孔隙率，表征限制对催化转化的影响，并研究光诱导电荷载流子产生的机制，跟踪它们的迁移率，并探测激子/极化子的定位。M. T. Elm是基于（光）电化学技术（包括各种环境中的阻抗谱）表征电子和离子传输特性的专家。通过这种方式，电荷载体的性质，它们的浓度和远程传输，以及缺陷对传输和催化转化效率的影响将被探测。

The overall goal of this project is to establish an integrated metal-organic framework (MOF) platform for photoelectrocatalytic water splitting to overcome the need for sacrificial donor/acceptor schemes prevailing in particulate systems. Our approach thus addresses the uncharted interface between MOF photocatalysis and electrocatalysis by elucidating and controlling the very fundamentals of light-driven charge transport and redox catalysis in bio-inspired MOF-co-catalyst hybrid architectures based on porphyrin linkers. A prerequisite for the design of efficient photoelectrochemical cells will be the development of (i) highly porous MOF systems with light harvesting and electronically communicating subunits, and of (ii) synthesis strategies for high quality homogeneous, oriented MOF thin film electrodes. Our approach will be guided by insights into structure, dynamics, optical characteristics and electronic as well as ionic transport properties of the MOF films by solid-state NMR spectroscopy and impedance spectroscopy, as well as (photo)electrochemical analysis of the light-induced redox processes, feeding back into the design loop to create MOF photoelectrodes with high activity for hydrogen and oxygen evolution, reduced overpotentials and long-term stability. To accomplish this highly interdisciplinary task the research groups of B. V. Lotsch, M. T. Elm and J. Senker add their complementary skills in the synthesis and characterization of structural and transport properties. The Lotsch group has long standing expertise on the synthesis of MOF nanomaterials, the growth of MOF thin films and their post-synthetic modification of MOFs. The Lotsch group will develop photoactive porphyrin- and pyrene-based MOF systems, which will be interfaced with molecular and heterogeneous co-catalysts to orchestrate the light-induced multi-electron redox processes, and cast into high quality thin film architectures. For the structure elucidation of the MOF architectures the Senker group will provide a large repertoire of state-of-the art NMR crystallographic strategies. A thin film NMR probe will be developed in his group to analyze the structural integrity and porosity of the MOF films, to characterize the impact of confinement on the catalytic conversion, and to study the mechanism of light-induced charge carrier generation, to follow their mobility, and to probe the localization of excitons/polarons. Complementary experiments are carried out by M. T. Elm who is an expert on characterizing the electronic and ionic transport properties based on (photo)electrochemical techniques including impedance spectroscopy in various environments. In this way the nature of charge carriers, their concentrations and long-range transport, as well as the influence of defects on the transport and efficiency of the catalytic conversion will be probed.