Selectivity Control under Dynamic CO2 Electroreduction Conditions

动态 CO2 电还原条件下的选择性控制

• 批准号: 406944504
• 负责人: Professor Dr. Olaf Magnussen
• 金额: --
• 依托单位: Institut für Experimentelle und Angewandte Physik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/406944504?language=en
• 关键词: Selectivity; Control; under; Dynamic; CO2

Electroreduction of carbon monoxide (CO2RR) on Cu-based electrocatalysts can provide significant yields of multi-carbon (C2+) products and thus opens a promising way for its conversion into valuable feedstock chemicals and fuels. Dynamic (potential pulsed) CO2RR has recently received significant attention, as it allows to periodically generate/restore distinct catalyst states and morphological motifs in situ, offering new possibilities for tuning the product selectivity, and regenerating poisoned catalyst surfaces. However, the active catalyst state and its dynamic evolution are still unclear and the detailed mechanisms of dynamic CO2RR require clarification.We will explore enhancing the CO2RR selectivity towards C2+ products using dynamic reaction conditions. Optimized conditions will be identified from extensive electro¬catalytic studies and studied in-depth by operando time-resolved methods. We aim to identify the influence of the potentiodynamic charac¬teris¬tics (pulse shape, range, and period) on the catalyst selectivity. By varying the anodic potential (to oxidizing and non-oxidizing conditions) and time regime (from ms to hours) different modifications of the electrode’s state are possible, such as changes in the surface charge, adsorbed species, redox state, and surface morphology. We will identify how this can improve the evolution of the C2+ selectivity and overcome catalyst poisoning to ensure stable catalyst activitiy and selectivity.Apart from pure Cu catalysts (Cu2O nanocubes, Cu single crystals) we will also study those decorated with secondary metal nanoparticles (Ag, Au, Zn) for tandem catalysis. Further-more, we will explore the selective promotion/inhibition of mechanistic pathways by chemical species (alkali cations, halide anions). For both, an increase in C2+ selectivity under potentiostatic conditions has been shown and we will extend these studies to the potentiodynamic case. For an improved understanding, the potential-dependent adsorption geometries, surface concentrations of the involved species (intermediates, inhibitors/promotors) and their influence on the Cu structure will be studied.For these studies, the FHI and CAU teams will employ their complementary expertise in operando techniques comprising a variety of spectroscopic (Raman, XAS) and X-ray scattering (powder and surface X-ray diffraction) as well as microscopic (STM/AFM) methods. These will provide comprehensive insights into the catalyst structure, adsorption geometry of important reaction intermediates (CO) and active spectator species as well as the dynamic changes of the catalyst’s properties. These insights will be directly correlated to the catalytic activity and C2+ selectivity. Furthermore, the FHI group will transfer the obtained understanding to electrolyzer-like gas-fed flow cells. Thereby, we will significantly contribute to a fundamental understand on the C2+ formation during CO2RR and especially, under potentiodynamic reaction conditions.

一氧化碳（CO2 RR）在铜基电催化剂上的电还原可以提供显着的多碳（C2+）产物产率，从而为将其转化为有价值的原料化学品和燃料开辟了一条有前途的途径。动态（电位脉冲）CO2 RR最近受到了极大的关注，因为它允许周期性地产生/恢复不同的催化剂状态和原位形态图案，提供了新的可能性，调整产品的选择性，并再生中毒的催化剂表面。然而，活性催化剂的状态及其动态演变仍然不清楚，动态CO2 RR的详细机制需要澄清。我们将探索利用动态反应条件提高CO2 RR对C2+产物的选择性。优化条件将从广泛的电催化研究中确定，并通过操作时间分辨方法进行深入研究。我们的目标是确定动电位特性（脉冲形状、范围和周期）对催化剂选择性的影响。通过改变阳极电位（氧化和非氧化条件）和时间制度（从毫秒到小时），可以对电极状态进行不同的修改，例如表面电荷、吸附物质、氧化还原状态和表面形态的变化。除了纯Cu催化剂（Cu 2 O纳米立方体、Cu单晶）外，我们还将研究那些用次级金属纳米颗粒（Ag、Au、Zn）修饰的串联催化剂。此外，我们将探讨化学物种（碱金属阳离子，卤素阴离子）的选择性促进/抑制的机制途径。对于这两个，增加C2+的选择性在恒电位条件下已被证明，我们将这些研究扩展到动电位的情况下。为了更好的理解，电位依赖的吸附几何形状，表面浓度的参与物种对于这些研究，FHI和CAU团队将利用他们在操作技术方面的互补专业知识，包括各种光谱技术，（拉曼，XAS）和X射线散射（粉末和表面X射线衍射）以及显微镜（STM/AFM）方法。这些将提供全面的洞察到催化剂的结构，吸附几何的重要反应中间体（CO）和活性旁观物种，以及催化剂的性能的动态变化。这些见解将与催化活性和C2+选择性直接相关。此外，FHI小组将把所获得的理解转移到类似电解槽的气体流通池中。因此，我们将大大有助于对CO2 RR过程中C2+形成的基本理解，特别是在动电位反应条件下。