Density functional investigation on structural, electronic and magnetic properties of ruthenium- or osmium-doped rhodium clusters and their application towards H 2 S gas sensing and activation

A density functional study is performed to establish the structural, electronic, magnetic and catalytic properties of ruthenium- or osmium-doped bimetallic as well as ruthenium-osmium-doped tri-metallic rhodium alloy clusters. Stability parameters like stability function, HOMO-LUMO gap and deformation electron density suggest a higher stability of Rh4Ru, Rh5Ru, Rh2Os, Rh4Os and Rh2RuOs. Rh2Ru, Rh2Os and Rh4RuOs also possess larger values of magnetic moment. Higher charge separations among atoms are noticed in tri-metallic in comparison to bimetallic alloys. HOMO and LUMO iso-surfaces as well as DOS diagrams reveal greater contribution of d-orbitals overlapping among all the atoms in the formation of alloy. These alloy clusters are observed to sense H2S gas in the presence of other abundant gases like O2, N2 and CO2. Alloy clusters can dissociate H2S via two steps with one intermediate and two transition states. Rh4Ru and Rh2RuOs clusters catalyse the dissociation of the S-H bond of H2S more effectively than other clusters.