Adsorption mechanism and competitive adsorption of As2O3 and NH3 molecules on CuO (111) surface: a DFT study.

Adsorption mechanism and competitive adsorption of NH3 and As2O3 molecules on CuO (111) surface were investigated via density functional theory (DFT) simulations. The adsorption configuration, adsorption energy, electronic gains/losses, and projected density of states were thoroughly discussed. Results showed that As2O3 molecule was more likely to adsorb on CuO surface than NH3 molecule. For the adsorption of As2O3 on CuO surface, the "Osuf-Osuf bridge" site was the active site with the chemical adsorption energy of -1.39 eV. In the process of NH3 adsorption on CuO surface, N-Cu bond was formed in chemical adsorption, which was mainly attributed to the charge transfer from NH3 molecule to substrate surface. However, no obvious structural change occurred in physisorption. Thermodynamic analysis indicated that physisorption was the primary form for the adsorption of NH3 and As2O3 molecules on CuO surface under the actual SCR condition.