IR STUDY ON H D ISOTOPE-EXCHANGE REACTIONS OF FORMATE AND METHOXY SPECIES WITH D-2 ON ZRO2/

H/D isotope exchange reactions of adsorbed formate [HCOO(a)] and metho xy [CH3O(a)] species with D-2 on ZrO2 have been investigated by FTIR s pectroscopy. The H/D exchange reaction of the formate proceeded only i n the presence of gaseous D-2 [D-2(g)] and not with surface OD groups. The rate determining step was concluded to be the activation of D-2(g ) with an activation energy of 95 +/- 8 kJ mol(-1) (473-573 K). On the other hand, methoxy species exchanged H atoms in the methyl group wit h the surface OD groups, even in the absence of D-2(g). The activation energy was measured to be 127 +/- 8 kJ mol(-1) (523-623 K).