ACID-BASE REACTIONS ON MODEL MGO SURFACES

Three MgO surfaces of different structures have been employed as models for study of the acid-base properties of MgO. Surface spectroscopies including XPS, UPS, and ISS were used to determine the nature and the absolute coverage of surface intermediates, and the nature of bonding sites upon adsorption of Bronsted acid molecules on these surfaces. Different behavior patterns of the Bronsted acid molecules with varying strengths on the three model surfaces provide insights into the site requirements for dissociation of Bronsted acids on MgO. The base-catalyzed Cannizzaro reaction of formaldehyde was observed on these model surfaces under UHV conditions.