Observation of Distinct Surface AlIV Sites and Phosphonate Binding Modes in Gamma-Alumina and Concrete by High-Field 27Al and 31P MAS NMR

Abstract

The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. High loadings of nerve agent-related phosphonic acids adsorbed on ?-Al2O3 and concrete examined by 31P MAS NMR and high-field 27Al MAS NMR reveal the presence of several phosphonate-surface binding modes and greatly improved resolution of multiple AlIV sites. Some of the resolved AlIV sites are sensitive to surface hydroxylation/dehydroxylation are attributed to surface AlIV-OH groups (apparently having been observed for the first time). Although the number of surface AlIV sites detected by high-field 27Al MAS NMR