Unveiling Coverage-Dependent Interactions of N-Methylaniline with the Pt(111) Surface

Area of Science:

• Surface Science
• Catalysis
• Computational Chemistry

Background:

• Aromatic amines are crucial in catalysis, but their surface chemistry and activation mechanisms on metal surfaces are not fully understood.
• N-methylaniline (NMA) serves as a model compound to investigate these processes on platinum.

Purpose of the Study:

• To elucidate the adsorption and surface chemistry of NMA on Pt(111).
• To understand the coverage-dependent activation mechanisms of aromatic amines on catalytic surfaces.

Main Methods:

• Density Functional Theory (DFT) calculations.
• Experimental techniques including temperature-programmed X-ray photoelectron spectroscopy (TP-XPS), temperature-programmed desorption (TPD), and Fourier transform infrared reflection absorption spectroscopy (FT-IRRAS).

Main Results:

• NMA adsorption and activation on Pt(111) are strongly dependent on surface coverage.
• At low coverages, NMA activates via phenyl ring binding, leading to C-N bond cleavage and hydrogen cyanide (HCN) formation.
• At high coverages, NMA binds through the nitrogen atom and desorbs intact without activation.

Conclusions:

• Coverage-dependent intermolecular interactions and charge transfer dictate NMA's surface chemistry and selective bond activation.
• These findings provide fundamental insights into the heterogeneous catalysis of aromatic amines, aiding the development of new catalytic strategies.