Investigating the adsorption behavior of NOx molecules on γ-Al2O3(1 0 0)-supported proximal Pt-Ba clusters using density functional theory

•The combined effect of the coexistence of carrier, catalyst and storage site on NOx adsorption was investigated.•The experimentally observed “fast” sites of NOx storage are reproduced by the model of the proximity of Pt-Ba clusters.•The interesting trend of NOx adsorption energy with different adsorption sites were systematically outlined.•Two interaction models, sNOx-pBa and pNOx-dPt, are proposed to explain the NOx activation mechanism.