Charge reordering of MgO (1 0 0) surface by Sn cluster deposition: Implications for heterogeneous catalysis

Abstract Catalysis with cluster-substrate complex materials has relevance for fundamental understanding and technological applications. Present work reports a systematic DFT study on Snn (n = 1–6, 10) cluster adsorbed on catalytically relevant MgO(1 0 0) substrate. Results reveal that Sn-Sn interaction is stronger than Snn-MgO interaction which helps in retaining gas phase motif during interaction. While smaller size tin clusters maximizes interaction with perfect MgO(1 0 0) surface through parallel orientation (more number of bond with surface atoms), larger cluster anchors on surface by single Sn-O bond only. Adsorption form of Sn cluster on perfect MgO surface are different from those reported in literature for gold cluster. Whilst gold cluster has been known for pulling charge from MgO, tin clusters provides electronic charge to MgO surface. Sn cluster reciprocate relatively higher reconstruction in MgO substrate due to charge transfer from adsorbate to substrate. This lead to significant reordering of electronic charge in MgO surface and induces variance in charge polarity across slab. Variance of charge polarity was reaffirmed by different adsorption behavior of water molecule across slab. Since ionic liquids has huge implications in catalyzing a solution phase reaction due to their polarity effect, likewise observed polarity variance along MgO surface endorses its implication in heterogeneous catalysis.