Abstract In this work is studied the adsorption and reduction of carbon monoxide, CO, catalyzed by neutral and charged iron clusters, through the Fen0, ±1 + 2CO → FenC0, ±1 + CO2 (n = 4, 7) reactions in… Click to show full abstract
Abstract In this work is studied the adsorption and reduction of carbon monoxide, CO, catalyzed by neutral and charged iron clusters, through the Fen0, ±1 + 2CO → FenC0, ±1 + CO2 (n = 4, 7) reactions in the gas phase. It was found, by means of all-electron density functional theory calculations, that the activation energy, Ea = 140 kcal/mol, for the Boudouard reaction, CO + CO → C + CO2, is considerably reduced, up to 33.6 and 58.2 kcal/mol, when the neutral Fe4 and Fe7 magnetic clusters acts as catalysts, respectively. Therefore, a primary role of Fen clusters is to decrease the barriers for dissociation of the CO molecule. For additional CO molecules reacting with the neutral products formed in the first reactions: the iron-carbon clusters Fe4C and Fe7C, results reveal that for the Fe4C + 2CO → Fe4C2 + CO2 process, the activation energy increases up to 44.7 kcal/mol. Notably, improvement in the catalytic behavior occurs for Fe7C since, for its correspondent reaction, it yields a smaller barrier, estimated as 44.8 kcal/mol. Low-lying states of charged Fe4 and Fe7 clusters interacting with CO molecules were characterized also. Overall, the neutral iron clusters produce smaller barrier energies than the charged Fe4,7±1 species.
               
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