Electrochemical Reduction of CO2

这项为期三年的研究项目的目的是深入了解将二氧化碳还原为碳氢化合物的双金属催化剂。这些催化剂将被优化为具有较高的稳定性、效率和大规模应用的可行性。这种反应的产物，如甲醇，可以直接用作燃料，也可以进一步合成更高效、更清洁的燃料，如甲氧基醚。因此，该研究项目将重点关注过渡金属，如铜、金和银，这些金属已经显示出高效和选择性二氧化碳电还原的前景。铜能直接将CO2还原为碳氢化合物，金、银以CO为主要产物。然而，这些金属仍有缺陷，阻碍了大规模的工业应用。例如，铜由于过电位大，选择性差，能源效率低。此外，它还受到电极上碳层的毒害。相比之下，黄金对这种中毒具有很高的稳定性，但价格非常昂贵。银的过电位低，选择性好，但CO易解吸，烃类较少。（Zhang, Zhao, and Gong 2017; Zhu, Liu, and Qiao 2016）为了克服这些关键缺陷，本研究项目将采用合金化的新方法。上述金属将与其他过渡金属合金化，在金和银的情况下产生有效的直接还原为甲醇。这可以通过例如铑、铟、铂、钯或钴来实现。至于铜，其目标是创造一种合金组合，具有更高的抗中毒稳定性和更好的能源效率。可能的合金是铜和锡，以及上面提到的金属与金和银。除了开发更高效和通用的双金属催化剂外，还将研究所采用的衬底和制备方法的影响。根据所需的结构和特性，将测试不同的电化学方法来制备催化剂。我们将特别关注催化剂和底物之间的物理相互作用。为了在工业规模上保证稳定和高效的反应，催化剂必须对反应器中的中毒和流动条件保持稳定。拟议的研究旨在防止催化剂和底物之间的松散连接，这将导致系统容易发生故障或选择性损失，从而随着时间的推移迅速提高效率。无论哪种方式，这样的系统都不能用于更大规模。

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.