Cobalt Oxide-Silica Core-Shell Nanotubes for Photodriven CO2 Reduction by H2O

用于通过 H2O 光驱动 CO2 还原的氧化钴-二氧化硅核壳纳米管

• 批准号: 298305337
• 负责人: Dr. Georgios Katsoukis
• 金额: --
• 依托单位: Physical Biosciences Division
• 依托单位国家: 德国
• 项目类别: Research Fellowships
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/298305337?language=en
• 关键词: Cobalt; Oxide; Silica; Core; Shell

The key challenge of this project is to develop and investigate charge transport and catalytic transformations of a macroscale array of spatially separated, vertically arranged cobalt oxide-silica core-shell nanotubes for photodriven carbon dioxide reduction by water. The goal is the optimization of the photocatalytic performance for closing the photosynthetic cycle under separation of the products. In this hierarchical construct, water oxidation catalysis proceeds on the cobalt oxide surface while carbon dioxide reduction takes place at a heterobinuclear photocatalytic unit separated from the cobalt oxide nanotube by the proton permeable, oxygen blocking silica layer. Molecular wires are embedded within the silican membrane in order to allow electronic communication between the half reactions. We will study the electron and proton transport properties of the photocatalytic system. The following scopes play important roles in the electrochemical and photophysical evaluation: i) steady proton flux through a few nanometer thin (amorphous, dense phase) silica layer, ii) molecular wire mediated visible light sensitized charge flow across the silica membrane, iii) charge transfer dynamics of the hole injection process from a chromophore through the silica embedded molecular wire to the cobalt oxide catalyst, and iv) relaxation and electron transfer dynamics by implementing carbon dioxide reducing heterobinuclear charge transfer chromophores. We will place special emphasis on the identification of branching ratios of the competing processes at the different sites of the photocatalytic cycle (i.e. carbon dioxide reduction site, light absorber, silica membrane, molecular wires, water oxidation site) that will guide catalyst design improvement. Closing the photosynthetic cycle on the nanoscale under product separation is a fundamental scientific challenge, which is an approach that minimizes side and cross reactions and other efficiency degrading processes. This is essential for scalability of photosynthesis on an appropriately large scale that will have an impact on renewable solar fuels generation.

该项目的关键挑战是开发和研究空间分离、垂直排列的氧化钴-二氧化硅核壳纳米管的宏观阵列的电荷传输和催化转化，用于光驱动二氧化碳的水还原。目标是优化光催化性能，从而在产物分离的情况下结束光合作用循环。在这种分层结构中，水氧化催化作用在氧化钴表面进行，而二氧化碳还原则在异双核光催化单元上进行，该光催化单元与氧化钴纳米管之间由质子可渗透、阻氧的二氧化硅层隔开。分子导线被嵌入到硅膜中，以便允许半反应之间的电子通信。我们将研究光催化体系的电子和质子输运性质。下列范围在电化学和光物理评估中发挥了重要作用：i)通过几个纳米薄(无定形、致密相)二氧化硅层的稳定质子通量，ii)分子线介导的可见光敏化电荷流过二氧化硅膜，iii)空穴通过二氧化硅嵌入分子线注入到氧化钴催化剂的电荷转移动力学，以及iv)通过二氧化碳减少异双核电荷转移发色团的驰豫和电子转移动力学。我们将特别强调在光催化循环的不同部位(即二氧化碳还原部位、光吸收部位、硅膜、分子线、水氧化部位)确定竞争过程的分支比率，以指导催化剂设计的改进。在产品分离的情况下关闭纳米尺度上的光合作用循环是一项基本的科学挑战，这是一种将副反应和交叉反应以及其他效率降低过程降至最低的方法。这对于光合作用在适当规模上的可伸缩性至关重要，这将对可再生太阳能燃料的产生产生影响。