First-principles prediction of NO2 and SO2 adsorption on MgO/(Mg0.5Ni0.5)O/MgO(100)

Highlights: • The NO₂ and SO₂ adsorption on MgO/(Mg_0.5Ni_0.5)O/MgO(1 0 0) was predicted using DFT methods. • The adsorption strength of NO₂ was higher than the strength of SO₂ on MgO/(Mg_0.5Ni_0.5)O/MgO(1 0 0). • Applied strains in the compressive (tensile) direction were useful to increase the NO₂ (SO₂) adsorption strength on MgO/(Mg_0.5Ni_0.5)O/MgO(1 0 0). • The higher adsorption strength of both adsorbates of NO₂ and SO₂ was observed on Ca-promoted MgO/(Mg_0.5Ni_0.5)O/MgO(1 0 0) than on Sr-promoted MgO/(Mg_0.5Ni_0.5)O/MgO(1 0 0). Developing high-performance adsorbents for NO₂ and SO₂ is a significant step in reducing air pollution. In this study, using first-principles modeling, NO₂ and SO₂ adsorption on MgO/(Mg_0.5Ni_0.5)O/MgO(1 0 0) was theoretically predicted. Adsorption of NO₂ was stronger than that of SO₂ on the MgO/(Mg_0.5N_i0.5)O/MgO(1 0 0) surface. Both structural and chemical changes were applied to MgO/(Mg_0.5Ni_0.5)O/MgO(1 0 0) in order to investigate strategies for improving the strength of adsorption of these gases on the MgO/(Mg_0.5Ni_0.5)O/MgO(1 0 0) system. NO₂ and SO₂ adsorption on MgO/(Mg_0.5Ni_0.5)O/MgO(1 0 0) was found to be tunable using the applied strain and certain promoters, such as Ca and Sr. The approach with the promoter more effectively enhanced the strength of NO₂ and SO₂ adsorption on MgO/(Mg_0.5Ni_0.5)O/MgO(1 0 0) than the approach with the applied strain. The interactions between the adsorbate (i.e., NO₂ and SO₂) and the MgO/(Mg_0.5Ni_0.5)O/MgO(1 0 0) surface were further elucidated through an investigation of the density of states and Bader charge.