Non-disruptive, detailed chemical information at the nanoscale is essential for understanding, on a single particle basis, how surface properties direct the reactivity of oxide-supported nanoparticles. We have recently demonstrated that IR nanospectroscopy measurements can provide high spatial resolution mapping of catalytic reactions on the surface of metallic nanoparticles, while using chemically active N-heterocyclic carbene molecules (NHCs)  as indicators for surface reactivity. Differently active regions within a given particle were distinguished by mapping the chemical reactivity of surface-anchored NHCs while using synchrotron radiation-based infrared nanospectroscopy measurements with a spatial resolution of 25 nm.<br/>Although it was demonstrated that NHCs can function as chemical indicators, the various properties of surface-anchored NHCs, such as their density, orientation, chemical and thermal stability have not yet been determined. In this work, NO<sub>2</sub>- and OH-functionalized NHCs were anchored to the surface of oxide-supported Pt and Au nanoparticles, as well as to the surface of Pt(111) and Au(111) single crystals. Surface sensitive techniques such as Infrared Reflection Absorption Spectroscopy, X-ray Photoelectron spectroscopy and Near Edge X-ray Absorption Fine Structures were employed to identify the properties of chemically-active, surface anchored NHCs. By comparing the properties of NHCs that were anchored on single crystals to NHCs that were anchored on nanoparticles we identified the influence of high density of surface defects on NHCs’ properties.<br/>

N-heterocyclic carbene molecules (NHCs) as chemical markers for high spatial resolution mapping of catalytic reactions on surfaces

255th National Meeting (2018)

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