Small gases adsorption and related reactions on CeO₂ nanoparticle

Abstract

Adsorptions of diatomic (H₂, N₂, O₂, CO, NO), triatomic (CO₂, N₂O, NO₂, H₂O, H₂S, SO₂) and polyatomic (C₂H₂, C₂H₄, CH₄, NH₃) gases on CeO₂ and Ce₂O₄ clusters were studied using the DFT/B3LYP/GEN method. Water adsorptions on Ce atom of CeO₂ and Ce₂O₄ clusters were found to be the most favorable process. The adsorption enthalpies for water adsorbed on the CeO₂ and Ce₂O₄ clusters are -51.45 and -52.45 kcal/mol, respectively. Energy gaps of CeO₂ and Ce₂O₄ clusters largely decreased after adsorptions of O₂ and NO gases. The CeO₂ and Ce₂O₄ clusters can therefore be used as the sensing materials for O₂ and NO detections. It was found that the CeO₂ reduced to the CeO cluster by H₂ gas is non-spontaneous reaction at 298 K; the Gibbs free energy of the reaction is 234.1 kcal/mol.