Photochemical Water Splitting at Soft Interfaces

尽管过去几年在直接分解水的可见光催化剂的性能方面取得了重大进展，但必须提高耐用性和翻转次数才能应用，而氧气和氢气产生步骤的结合仍然是一个挑战。用于分解水的分子光催化剂通常由几个组分组成。我们提出了将具有光活性的两亲组分共嵌入到水-脂界面的膜结构中，从而可以方便地组装多组分催化剂体系的二维阵列。催化剂亚单位在界面的接近和高的局部浓度提高了光催化性能。嵌入的染料、催化剂和膜两亲性的组成的简单变化使多组分催化剂的快速优化成为可能。根据应用的两亲分子的性质，化合物在界面上的空间分布可能会受到影响，从而产生高活性的催化剂斑块。由于聚集体的动态性质，聚集体的自我修复将导致光催化剂的长期稳定性。中国申请者开发了用于可见光驱动的水氧化和制氢的金属络合物多组分催化剂。催化剂属于目前已知的性能最好的系统。这家德国集团在金属络合物的膜包埋和有机染料作为光敏剂的使用方面拥有经验。理想的互补专业知识将结合在一起，开发具有嵌入式多组份光催化剂的功能化囊泡和膜，并优化其性能。一项已经完成的联合初步研究表明，这种功能化的囊泡在蓝光下表现出光催化水氧化作用，并超过了这些成分在均相溶液中的性能。部分金属络合物光催化剂将被氧化还原活性有机染料取代，以降低体系的整体金属含量。制氢催化剂将被共嵌入，以获得同时产生氧气和氢气的膜。功能化的囊泡将在均匀的溶液中进行研究和优化，然后转移到表面或使用打印技术进行处理。这将允许简单地制备具有分层结构的复杂的多组分光活性器件。通过各参与组之间的博士生和博士后交流以及各组的年度联合讲习班，确保了项目内的知识转让和深入合作。

Although significant progress was made over the last years in the performance of visible light photocatalysts for direct water splitting, durability and turn over numbers must be improved to reach applications and the combination of the dioxygen and the dihydrogen generating steps remains a challenge. Molecular photocatalysts for water splitting typically consist of several components. We proposed the co-embedding of photoactive amphiphilic components into membrane structures at the water-lipid interface allowing facile assembly of two dimensional arrays of multi-component catalyst systems. The close proximity and the high local concentration of the catalyst subunits at the interface increase the photocatalytic performance. Simple variation of the composition of the embed¬ded dyes, catalysts and membrane amphiphiles allows the rapid optimization of the multi component catalysts. Depending on the nature of the applied amphiphiles the spatial distribution of compounds at the interface can be influenced leading to catalyst patches of high activity. Due to the dynamic nature of the assemblies self-repair of the aggregates should lead to a prolonged stability of the photocatalysts.The Chinese applicants have developed metal complex based multi-component catalysts for visible light driven water oxidation and hydrogen generation. The catalysts belong to the best performing systems currently known. The German group has experience in membrane embedding of metal complexes and the use of organic dyes as photosensitizers. The ideally complementary expertise will be combined to develop functionalized vesicles and membranes with embedded multi-component photocatalysts and the optimization of their performance. An already completed joint initial study revealed that such functionalized vesicles show photocatalytic water oxidation using blue light and exceed the performance of the components in homogeneous solution. Part of the metal complex photocatalysts will be replaced by redox active organic dyes to reduce the overall metal content of the system. Hydrogen generating catalysts will be co-embedded to obtain membranes performing simultaneous oxygen and hydrogen generation. Functionalized vesicles will be investigated and optimized in homogeneous solution, and then transferred onto surfaces or processed using printing technology. This will allow the facile preparation of complex multi-component photoactive devices with hierarchical architecture. Knowledge transfer and intensive collaboration within the project is ensured by exchange of PhD students and postdocs between the participating groups and an annual joint workshop of the groups.