NSF-DFG Echem: Design of Nanostructured Noble - Metal Chalcogenide Electrocatalysts for Hydrogen Evolution Reaction

层状贵金属（Pd，Pt）硫族化合物（M：Pt或Pd，X：Se或Te）作为电化学析氢反应（HER）的活性催化剂已被提出，但其催化作用的细节还远未被理解。这可能部分与这些材料中的强层间相互作用和尺寸量子化效应有关，这导致它们的电子性质根据层的数量而发生显著的变化。与此同时，这些物理效应也可能为这些材料中催化性能的定制开辟新的途径。此外，在台阶边缘处具有特殊电子性质的欠配位原子的受控设计也可以增加高活性催化位点的丰度。在这个项目中，我们将确定活性成分相以及这些贵金属硫属化物材料的纳米结构（层数和台阶边缘密度）如何用于提高HER活性。我们还打算利用广泛的过渡金属二硫属化物（TMD）的结构相似性作为材料平台，以研究TMD相混合物（合金）中可能的协同效应，以提高HER活性。我们设想，这些材料的平面性质将有助于表征混合相材料的结构和电子性质，从而促进对多组分材料中协同效应的基本理解。为了进行这些研究，我们组建了一个拥有互补专业知识和能力的团队。美国南佛罗里达大学的Batzill小组将通过货车德瓦尔斯外延合成平面模型系统，并通过扫描探针显微镜和光电子能谱表征其原子结构和电子性质。这些定义明确的样品的电化学性能，迄今为止在电化学界研究得很差，将在布伦瑞克的Oezaslan小组进行分析。 实验确定的微观动力学的结果将合理化，通过从头计算模拟将在Krasheninnikov的小组在亥姆霍兹Zentrum德累斯顿-Rossendorf。合金和掺杂剂的理论预测也将指导实验，并有助于确定有前途的材料组合。该团队包括材料的详细表征，以便动力学参数和HER活性与其物理和化学性质相关。该项目的成果是确定新的潜在的电催化剂HER和可控纳米结构的可调性。这些研究不仅将为先进低维材料的催化作用提供基础知识，还将为先进电催化剂的实际设计确定新的途径，从而为社会寻找生态能源解决方案做出贡献。

Layered noble metal (Pd, Pt) chalcogenides with structural formulas ranging from MX2 to MX (M: Pt or Pd, and X: Se or Te) have been proposed as active catalysts for the electrochemical hydrogen evolution reaction (HER), but the details of the catalytic action are far from being understood. This may be related in part to strong interlayer interactions and size quantization effects in these materials, which cause significant modifications of their electronic properties depending on the number of layers. At the same time, these physical effects may also open new avenues to the tailoring of catalytic properties in these materials. Moreover, controlled design of undercoordinated atoms at step edges with special electronic properties may also increase the abundance of highly active catalytic sites. In this project, we will identify the active compositional phases and how nano-structuring (number of layers and step edge density) of these noble metal chalcogenide materials may be used to boost the HER activity. We also intend to utilize the structural similarities of a wide range of transition metal dichalcogenides (TMDs) as a materials platform to investigate possible synergetic effects in TMD-phase mixtures (alloys) to enhance HER activity. We envision that the planar nature of these materials will aid the characterization of structural and electronic properties of mixed-phase materials and thus facilitate the fundamental understanding of synergetic effects in multi-component materials. To conduct these studies, we assembled a team with complementary expertise and capabilities. Planar model systems will be synthesized by van der Waals epitaxy, and their atomic structure and electronic properties will be characterized by scanning probe microscopy and photoemission spectroscopy in the Batzill’s group at University of South Florida, USA. The electrochemical properties of these well-defined samples, so far poorly investigated in the electrochemistry community, will be analyzed at the TU Braunschweig in the Oezaslan’s group. The experimentally determined micro-kinetics results will be rationalized through ab initio simulations to be done in Krasheninnikov’s group at the Helmholtz Zentrum Dresden-Rossendorf. The theoretical predictions for alloys and dopants will also guide the experiments and help to identify promising materials combinations. This team encompasses detailed characterization of the materials so that the kinetic parameters and HER activities can be correlated with their physical and chemical properties. The outcome of this project is the identification of new potential electrocatalysts for HER and their tunability by controlled nano-structuring. These studies will not only provide fundamental knowledge on the catalytic action of advanced low-dimensional materials, but also define new pathways for the practical design of advanced electrocatalysts, and thus contribute to finding ecological energy solutions for the society.