Electrochemical Reduction of CO2

这个为期三年的研究项目的目的是更深入地了解将CO2还原为碳氢化合物的催化剂。这些催化剂将被优化w.r.t.稳定性高，效率高，可大规模应用。该反应的产物（如甲醇）可以直接用作燃料或进一步合成为更高效和清洁的燃料（如氧亚甲基醚）。因此，本研究项目将重点关注过渡金属，如铜，金和银，它们已经显示出有效和选择性的CO2电还原的前景。铜能直接将CO2还原为碳氢化合物，金和银以CO为主要产物。然而，这些金属仍然存在缺陷，阻碍了大规模的工业应用。例如，在一个示例中，铜具有差的选择性以及由于大的过电位而导致的低能量效率。此外，它会被电极上的碳层毒害。相比之下，金对这种中毒具有高稳定性，但非常昂贵。银具有低的过电位和良好的选择性，但CO容易解吸，导致较少的烃。（Zhang，Zhao，and Gong 2017; Zhu，Liu，and Qiao 2016）为了克服这些关键缺陷，本研究项目将使用合金化的新方法。在金和银的情况下，上述金属将与其它过渡金属合金化以产生有效的直接还原成甲醇。这可以通过例如铑、铟、铂、钯或钴来实现。关于铜，目标是创造一种具有更高的抗中毒稳定性以及更好的能量效率的合金组合。可能的合金是铜和锡以及上述金属与金和银。除了开发更有效和多用途的催化剂外，还将研究所用基底和制备方法的影响。根据所需的结构和特性，将测试用于制备催化剂的不同电化学方法。一个特别的焦点将设置在催化剂和基板之间的物理相互作用。为了确保在工业规模上稳定和有效的反应，催化剂必须对反应器中的中毒和流动条件稳定。拟议的研究旨在防止催化剂和底物之间的松散连接，这将导致系统易于故障或选择性损失，从而随着时间的推移迅速降低效率。无论哪种方式，这样的系统都不能在更大范围内使用。

The aim of this three-year research project is to gain deeper insight into bimetallic catalysts for the reduction of CO2 to hydrocarbons. These catalysts will be optimised w.r.t. high stability, efficiency and feasibility of large-scale applications. Products of this reaction such as methanol can be directly used as fuel or be further synthesised to more efficient and clean fuels like Oxymethylenether.Consequently, this research project will focus on transition metals, e.g. copper, gold, and silver, which have already shown promise for an efficient and selective CO2 electroreduction. Copper is able to directly reduce CO2 to hydrocarbons, gold and silver have CO as main product. However, these metals still have flaws preventing large-scale industrial use. E.g., Copper has a poor selectivity as well as a low energy-efficiency due to a large overpotential. In addition, it is poisoned by a carbon layer on the electrode. In contrast, gold has a high stability against such poisoning, but is very costly. Silver has a low overpotential and good selectivity, but CO is easily desorbed leading to a less hydrocarbons. (Zhang, Zhao, and Gong 2017; Zhu, Liu, and Qiao 2016)In order to overcome these critical flaws, the novel approach of alloying will be used in this research project. The aforementioned metals will be alloyed with other transition metals to generate an efficient direct reduction to methanol in the case of gold and silver. This might be achieved by e.g. rhodium, indium, platinum, palladium or cobalt. Concerning copper, the aim is to create an alloy combination with a higher stability against poisoning as well as a better energy-efficiency. Possible alloys would be copper and tin as well as the metals mentioned above with gold and silver.In addition to developing a more efficient and versatile bimetal catalyst, the influence of the employed substrate and preparation method will be investigated. Depending on the desired structure and characteristics, different electrochemical methods for the preparation of the catalyst will be tested. A special focus will be set on the physical interaction between catalyst and substrate. To ensure a stable and efficient reaction on an industrial scale, the catalyst must be stable against poisoning and flow conditions in the reactor. The proposed research aims at preventing a loose connection between catalyst and substrate which would result in a system prone to breakdowns or losses in selectivity and thus efficiency quickly over time. Either way, such a system cannot be used on a larger scale.