Monitoring Catalytic reactions on Nanoparticles by solid state NMR: a joint experimental and theoretical approach

该项目旨在研究由有机金属前体和辅助配体（磷化氢和n杂环碳）制备的金属纳米颗粒（Ru, Pd, Au, RuCu）对代表性催化反应的表面反应性，即i) CO氧化作为一个有充分记录的例子，ii)胶态催化的芳烃加氢，iii)大规模非均相催化的Fischer- Tropsch合成（FTS）。反应过程将由各种核磁共振实验监测。在情况i)和iii)中，将使用气相核磁共振与质谱相结合来表征反应过程和产物，而在情况ii中，将使用溶液核磁共振（包括DOSY）。固体核磁共振将表征表面物质、它们的位置和动力学。更准确地说，表面氘的位置和动力学将通过温度依赖的静态固体核磁共振来实现。13CO将作为探针分子定位辅助配体，直接或选择性地确定反应位点，并监测颗粒对CO氧化和费托合成的反应活性。为此，将使用可变温度13C MAS-NMR光谱。这些实验将与使用DFT方法在现实模型上定位配体和确定反应途径的理论方法密切相互作用（Ru55）。这将有助于验证实验结果（例如氘的位置）和了解吸附物的行为，以便提出催化反应的模型。

The project aims at studying the surface reactivity of metal nanoparticles (Ru, Pd, Au, RuCu) prepared from organometallic precursors and accommodating or not ancillary ligands (phosphines and N-heterocyclic carbenes) towards representative catalytic reactions, namely i) CO oxidation as a well-documented example, ii) arene hydrogenation for colloidal catalysis and iii) Fischer- Tropsch synthesis (FTS) for large scale heterogeneous catalysis. The course of the reactions will be monitored by various NMR experiments. Gas phase NMR, associated with mass spectrometry, will be used to characterize the course of reactions and the products in cases i) and iii) whereas solution NMR (including DOSY) will be used in case ii). The surface species, their location and dynamics will be characterized by solid state NMR. More precisely, surface deuterides location and dynamics will be achieved by temperature dependant static solid state NMR. 13CO will be used as a probe molecule to locate ancillary ligands, to determine directly or by selectively poisoning the reactions sites and to monitor the reactivity of the particles towards CO oxidation and Fischer-Tropsch Synthesis. For this purpose, variable temperature 13C MAS-NMR spectroscopy will be used. These experiments will be carried out in close interaction with a theoretical approach using DFT methods to locate the ligands and determine the reactions pathways on realistic models (Ru55). This will help both to validate experimental results (for example deuterium location) and understand the behavior of the adsorbates in order to propose a model of the catalytic reactions.