Abstract: The adsorption of HCHO molecules on perfect and S-deficient FeS₂(100) surfaces was studied with a periodic slab model by Perdue-Burke-Ernzerhof approach of General Gradient Approximation within the framework of the density functional theory. The calculated results show that HCHO reacted with both surfaces through the O atom. HCHO adsorbed aslant on the Fe-top site on the perfect surface, while there were two stable structures for HCHO on the S-deficient surface, where HCHO bonded with one and two fourfold-coordinate Fe cations, respectively. The calculation of density of states, Mulliken population, and vibrational frequencies of the adsorption systems indicated that the electrons transferred from the substrate to HCHO, and the bond of C=O was elongated and weakened.

Key words: density functional theory, pyrite(100), perfect surface, S-deficient surface, formaldehyde, adsorption