This paper describes the use of electrostatic assemblies of negatively charged colloidal CuInS₂/ZnS quantum dot (QD) sensitizers and positively charged, trimethylamino-functionalized iron tetraphenylporphyrin catalysts (FeTMA) to photoreduce CO₂ to CO in water upon illumination with 450 nm light. This system achieves a turnover number (TON) of CO (per FeTMA) of 450 after 30 h of illumination, with a selectivity of 99%. Its sensitization efficiency (TON per Joule of photons absorbed) is a factor of 11 larger than the previous record for photosensitization of an iron porphyrin catalyst for this reaction, held by a system in which both QDs and metal porphyrin were uncharged. Steady-state and time-resolved optical spectroscopy provides evidence for electrostatic assembly of QDs and FeTMA. Control of the size of the assemblies with addition of a screening counterion, K⁺, and a correlation between their measured size and their catalytic activity, indicates that the enhancement in performance of this system over the analogous uncharged system is due to the proximity of the FeTMA catalyst to multiple light-absorbing QDs and the selective formation of QD–FeTMA contacts (rather than QD–QD or FeTMA–FeTMA contacts). This system therefore shows the ability to funnel photoinduced electrons to a reaction center, which is crucial for carrying out reactions that require multistep redox processes under low photon flux, and thus is an important advance in developing artificial photocatalytic systems that function in natural light.

中文翻译：

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量子点和卟啉铁的光催化活性上层结构将水中的CO ₂还原为CO

本文介绍了使用带负电的胶体CuInS ₂ / ZnS量子点（QD）增感剂和带正电的三甲基氨基官能化的四苯基卟啉铁（FeTMA）的静电组件来光还原CO _{2的方法。}在450 nm的光照射下，转化为水中的一氧化碳。该系统在照射30小时后可达到450（每FeTMA）CO的转换数（TON），选择性为99％。它的敏化效率（每焦耳吸收的焦耳TON值）比以前的铁卟啉催化剂对该反应的光敏记录要大11倍，该记录由QD和金属卟啉均不带电的系统保持。稳态和时间分辨光谱为QD和FeTMA的静电组装提供了证据。通过添加筛选抗衡离子K ^+来控制组件的大小，以及它们的测量尺寸和催化活性之间的相关性，表明该系统的性能优于类似的不带电系统是由于FeTMA催化剂与多个吸光QD接近并且选择性形成了QD–FeTMA接触（而不是QD–QD或FeTMA–FeTMA接触）。因此，该系统显示出将光诱导电子集中到反应中心的能力，这对于在低光子通量下进行需要多步氧化还原过程的反应至关重要，因此是开发在自然光下起作用的人工光催化系统的重要进展。