Ashraf Bushra, Brinkmann Nils, Austin Dave, Le Duy, Al-Shamery Katharina, Rahman Talat S
Department of Physics, University of Central Florida, Orlando, Florida 32816, United States.
Institute of Chemistry, Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany.
J Phys Chem C Nanomater Interfaces. 2025 Mar 21;129(13):6196-6210. doi: 10.1021/acs.jpcc.4c08116. eCollection 2025 Apr 3.
This study aims to elucidate the adsorption and surface chemistry of -methylaniline (NMA) on Pt(111), using it as a model molecule to probe the activation mechanisms of aromatic amines on catalytic surfaces. Through a combination of density functional theory (DFT) calculations and experimental techniques such as temperature-programmed X-ray photoelectron spectroscopy (TP-XPS), temperature-programmed desorption (TPD), and Fourier transform infrared reflection absorption spectroscopy (FT-IRRAS), we explored the coverage-dependent behavior of NMA on Pt(111) to identify key steps in the activation process. The population of certain reaction paths is driven by a coverage-dependent balance between molecule surface charge transfer and intermolecular interactions, dictating the selective activation of specific bonds. Our findings reveal how coverage influences the orientation and bonding of NMA on the Pt(111) surface. At lower coverages, the molecule binds to the surface through the phenyl ring and activation, facilitating C-N bond cleavage to the ring under HCN formation. In comparison, at higher coverages, the molecule binds only through the nitrogen atom and desorbs intact. These insights into variable bond activation lay the groundwork for understanding the fundamental processes involved in potential heterogeneously catalyzed reactions of aromatic amines, contributing to the development of new catalytic strategies.
本研究旨在阐明对甲基苯胺（NMA）在Pt(111)上的吸附和表面化学性质，将其用作模型分子来探究芳香胺在催化表面上的活化机制。通过结合密度泛函理论（DFT）计算和程序升温X射线光电子能谱（TP-XPS）、程序升温脱附（TPD）以及傅里叶变换红外反射吸收光谱（FT-IRRAS）等实验技术，我们探究了NMA在Pt(111)上随覆盖度变化的行为，以确定活化过程中的关键步骤。某些反应路径的反应几率受分子表面电荷转移和分子间相互作用之间随覆盖度变化的平衡驱动，决定了特定键的选择性活化。我们的研究结果揭示了覆盖度如何影响NMA在Pt(111)表面的取向和键合。在较低覆盖度下，分子通过苯环与表面结合并活化，在形成HCN的情况下促进C-N键断裂至苯环。相比之下，在较高覆盖度下，分子仅通过氮原子与表面结合并完整脱附。这些关于可变键活化的见解为理解芳香胺潜在多相催化反应所涉及的基本过程奠定了基础，有助于开发新的催化策略。
