Thermal Dihydrogen Activation by a Closed-Shell AuCeO₂⁺ Cluster

Laser-ablation-generated AuCeO₂⁺ and CeO₂⁺ oxide clusters were mass-selected using a quadrupole mass filter and reacted with H₂ in an ion trap reactor at ambient conditions. The reactions were characterized by mass spectrometry and density functional theory calculations. The gold–cerium bimetallic oxide cluster AuCeO₂⁺ is more reactive in H₂ activation than the pure cerium oxide cluster CeO₂⁺. The gold atom is the active adsorption site and facilitates the heterolytic cleavage of H₂ in collaboration with the separated O^2– ion of the CeO₂ support. To the best of our knowledge, this is the first example of thermal H₂ activation by a closed-shell atomic cluster, which provides molecular-level insights into the single gold atom catalysis over metal oxide supports.