Determining the Surface Structure of Silicated Alumina Catalysts via Isotopic Enrichment and Dynamic Nuclear Polarization Surface-Enhanced NMR Spectroscopy.

ABSTRACT: Isotopic enrichment of ²⁹Si and DNP-enhanced NMR spectroscopy are combined to determine the detailed surface structure of a silicated alumina catalyst. The significant sensitivity enhancement provided by DNP is vital to the acquisition of multinuclear and multidimensional experiments that provide information on the atomic-level structure of the species present at the surface. Isotopic enrichment not only facilitates spectral acquisition, particularly given the low (1.5 wt %) Si loading, but also enables spectra with higher resolution than those acquired using DNP to be obtained. The unexpected similarity of conventional, CP, and DNP NMR spectra is attributed to the presence of adventitious surface water that forms a sufficiently dense ¹H network at the silica surface

SUBMITTER: Rankin AGM 

PROVIDER: S-EPMC5722451 | biostudies-literature | 2017 Oct

REPOSITORIES: biostudies-literature