IR study on H/D isotope exchange reactions of formate and methoxy species with D2 on ZrO2

Abstract

H/D isotope exchange reactions of adsorbed formate [HCOO(a)] and methoxy [CH ₃ O(a)] species with D ₂ on ZrO ₂ have been investigated by FTIR spectroscopy. The H/D exchange reaction of the formate proceeded only in 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) withan activation energy of 95±8 kJ mol ^-1 (473–573 K). On the other hand, methoxy species exchanged H atoms in the methylgroup with 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).