Adsorption of NO on Fe3O4(111)

Highlights: • NO adsorption on Fe₃O₄(111) is studied by means of DFT and simulated TPD spectra. • In agreement with experiment two distinct adsorption sites are found. • Experimental assignments to tetrahedral and octahedral Fe sites are confirmed. • Calculated IR spectra indicate the presence of two vibrational modes. • The presence of a single band in experiment is explained by coupled NO stretch modes. Adsorption of NO on Fe₃O₄(111) is studied by density functional theory (DFT) calculations. NO is preferably adsorbed atop the octahedral site which has a clearly higher adsorption energy than the tetrahedral site. The difference in adsorption energy correlates with differences in adsorption geometries and NO stretch vibrations. The results are in good agreement with temperature programmed desorption (TPD) and reflection-adsorption IR spectroscopy (RAIRS) measurements and provide an explanation of the observation of only one vibrational mode despite two distinct TPD features.