Hybrid PhotoElectrodes for Selective Reduction of CO2 into Solar Fuels

太阳能驱动的化学将二氧化碳还原为C1化合物是实现化学品和燃料可持续生产的最直接途径。然而，尽管我们已经获得了用于高效还原二氧化碳的分子催化剂和用于光驱动传输所需高能电子的高性能光电极，但用于太阳能到化学能转换的分子催化剂的应用尚未成熟。如果开发得当，这种分子催化剂和光电极的结合可以为碳利用和无化石能源生产提供可持续的解决方案。然而，两个主要的瓶颈阻碍了复合光电极的应用：1.光电流往往远低于基于催化剂和光电极的固有性质的预期，这是因为与半导体元件的界面影响催化剂的性能或受到界面电荷转移缓慢的限制。2.CO2转化的选择性往往受到催化剂局部环境(局部pH值、CO2浓度梯度、周围介质的介电常数、电位梯度)的影响。Hyphe-C1项目将解决这两个瓶颈：我们的总体目标是同时最大限度地提高催化速率和产品选择性，通过电子传导矩阵将催化剂集成到光电极上，最终实现高效的光驱动二氧化碳还原为CO、甲醛和甲醇，从而控制还原过程从2个电子到6个电子。

Solar driven chemistry for CO2 reduction to C1 compounds is the most direct route to sustainable production of chemicals and fuels. However, the application of molecular catalysts for solar to chemical energy conversion has not yet reached maturity even though we have access to molecular catalysts for efficient reduction of CO2 and high performance photoelectrodes for light-driven delivery of the required high energy electrons. If exploited appropriately, the combination of such molecular catalysts and photoelectrodes could offer sustainable solutions for carbon utilization and fossil-free energy generation. However, two major bottlenecks impair the applications of hybrid photoelectrodes: 1. Photocurrents are often far below those expected based on the intrinsic properties of the catalyst and of the photoelectrode because the interfacing with the semiconductor component affects the catalysts properties or is limited by slow interfacial charge transfer. 2. Selectivity in CO2-conversion is often affected by the local environment of the catalyst (local pH values, gradients in CO2 concentration, permittivity of the surrounding medium, potential gradients). The project HYPHE-C1 will address both bottlenecks: Our overarching goal is to concomitantly maximize the catalytic rates and the product selectivity, by integrating the catalyst on a photoelectrode by means of electron conducting matrices to ultimately achieve highly efficient light driven CO2 reduction to CO, formaldehyde and methanol, thus controlling the reduction process from 2 to 6 electrons.