Catalytic hydrolysis of COS over CeO2 (110) surface: A density functional theory study

Density functional theory (DFT) calculations were performed to investigate the reaction pathways for catalytic hydrolysis of COS over CeO2 (110) surface using Dmol(3) model. The thermodynamic stability analysis for the suggested routes of COS hydrolysis to CO2 and H2S was evaluated. The absolute values of adsorption energy of H2O-CeO2 are higher than that of COS-CeO2. Meanwhile, the adsorption energy and geometries show that H2O is easier adsorbed on the surface of CeO2 (110) than COS. H2O plays a role as a bridge in the process of joint adsorption. H2O forms more Ce-O-H groups on the CeO2 (110) surface. CeO2 decreases the maximum energy barrier by 76.15 kcal/mol. The migration of H from H2O to COS is the key for the hydrolysis reaction. C-O channel is easier to occur than C-S channel. Experimental result shows that adding of CeO2 can increase COS removal rate and prolong the 100% COS removal rate from 180 min to 210 min. The difference between Fe2O3 and CeO2 for the hydrolysis of COS is characterized in the atomic charge transfer and the formation of H-O bond and H-S bond. The transfer effect of H in H2O to S in COS over CeO2 decreases the energy barriers of hydrolysis reaction, and enhances the reaction activity of COS hydrolysis. (C) 2017 Elsevier B.V. All rights reserved.