INFRARED STUDIES OF THE ADSORPTION-DESORPTION OF WATER ON MONOCLINIC AND TETRAGONAL ZrO2 AS A FUNCTION OF TEMPERATURE

摘要

The adsorption-desorption cycling studies at elevated temperatures of submonolayer water coverages on the surface of two zirconium oxide poly¬morphs leads to a partial resolution of the vibrational frequencies due to chemisorbed and physisorbed species. The narrow stretching frequency band, u(O1-H)M for the monoclinic phase ZTO2-G, at 3760 cm-1 is assigned to chemisorbed OH groups bound to a single cation at crystal corners and edges. This singly coordinated anion is here designated as a "free" hydroxyl anion. This orientation enables the anion to accept an H-bonding donor water molecule. The polarizing effect of the H-bond lowers the stretch frequency of this hydroxyl anion.