Isotope-exchange reaction between hydrogen molecules and surface hydroxy groups on bare and modified ZrO2

The isotope-exchange reaction between molecular D2 and OH species on bare (b-) and modified with adsorbed formate (f-) and methoxy (m-) ZrO2 has been studied. On the b-ZrO2, the reaction rate was proportional to PD21/2, suggesting that the rate-determining step is the migration of D atoms. The initial activation energies (E‡) were 35 and 41 ± 4 kJ mol–1 for terminal (t-) and bridging (b-) OH groups, respectively, and increased as the reaction progressed, indicating the heterogeneity of the surface activation barrier for migration of D atoms. The kinetics of the exchange reaction on f- and m-ZrO2 was found to be different from that of b-ZrO2.