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 "O_suf-O_suf 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.