Efficient hydrogenation over single-site bimetallic RuSn clusters

Hydrogenation of ethene to ethane over single-site RuN and (RuSn)N clusters is investigated using Density Functional Theory calculations. The critical transition state barrier, namely the last hydrogenation step, correlates linearly for RuN with the adsorption energies of the reactants. Addition of Sn to the Ru-clusters breaks this relation and allows for lower reaction barriers. In general, Sn is found to have pronounced effects on the geometrical and electronic properties of RuN clusters with N≤ 12. RuN clusters preferably adopt cubic conformations with high spin states, whereas (RuSn)N have low spin states and form compact Ru cores capped with Sn atoms.