Acid-base reactions on model MgO surfaces

Abstract

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 Brønsted acid molecules on these surfaces. Different behavior patterns of the Brønsted acid molecules with varying strengths on the three model surfaces provide insights into the site requirements for dissociation of Brønsted acids on MgO. The base-catalyzed Cannizzaro reaction of formaldehyde was observed on these model surfaces under UHV conditions.