Investigating Local Structure in Layered Double Hydroxides with 17O NMR Spectroscopy

A new method based on the “memory effect” for efficient and economical 17O labeling of layered double hydroxides (LDHs) is introduced. High-quality 17O solid-state NMR spectra are obtained, for the first time, for LDHs prepared with only several hundred microliters of 17O-enriched H2O. The 17O resonances due to the different oxygen ions in the structure of LDHs can be resolved with better resolution than the results obtained from 1H ultrafast magic angle spinning (MAS) NMR spectroscopy. The results show clear evidence for Al–O–Al avoidance. Since only intermediate MAS speeds and fields are used, this new approach can be incorporated easily with a variety of dipolar recoupling schemes to explore the key interactions and applications of LDHs.