Theoretical study of H2 dissociation on a ZrO2 cluster

► H2 reacts with ZrO2 leading to ZrO plus water elimination. ► Two pathways are found to be competitive, both involve a spin inversion. ► Hydride/hydroxyl containing species is the most stable intermediate. ► Zr(OH)2 is a stable intermediate and corresponds to a reduced zirconium site. ► Singlet and triplet states are found to be close in energy in reduced structures.